SAFETY, INSTALLATION & OPERATION MANUAL

                                        SAFETY, INSTALLATION & OPERATION MANUAL

FOR

 H₂ TYPE STEAM OPERATED SINGLE EFFECT LITHIUM BROMIDE ABSORPTION CHILLER

Chapter 1 DESCRIPTION OF ABSORPTION CHILLER

1.1 Description of Formation of Type Number

□   -----□    □     

                

             

               

                 Design number: H₂ (H₂-type Unit)

                 Nominal cooling capacity: (USRT)

                 Chiller type: SS-steam operated single effect lithium bromide absorption chiller

Type Example:

SS-331H₂ will be the H₂ type steam operated single effect lithium bromide absorption chiller with steam pressure 0.1MPa(G), cooling capacity 331USRT, chilled water inlet/outlet temperature 12/7°C and MMI2 control.

1.2 The Nominal Operation Conditions and Working Limits

For the nominal operation conditions of chiller, see data on the nameplate.

Allowed working limits:

Chilled water outlet temperature (t): Nominal value minus 2°C£ t £ Nominal value plus 3°C Cooling water inlet temperature (t): 18°C£ t £ 34°C

Nominal working steam pressure: Not more than nominal working steam pressure plus 0.05MPa

1.3 Configuration of Chiller

H2 type Steam-operated single effect lithium bromide absorption chiller (shortened as chiller hereinafter) is a equipment, which uses saturated steam as heat source, water as refrigerant, lithium bromide as absorbent, produces the chilled water under vacuum conditions for the purpose of air-conditioning and technology process.

The chiller consists of following main parts: generator, condenser, evaporator, absorber, heat exchangers; and such auxiliary parts as purging unit, de-crystallization piping and hermetically-sealed pumps (solution pump and refrigerant pump). The external view of absorption chiller is shown in the Fig. 1-1, 1-2 and 1-3. The valves for different chillers are listed in Table 1-1.

1.        Gas cylinder 2.        Upper purging valve of vacuum pump  3.        Lower purging valve of vacuum pump  4.        Purging sampling valve  5.        Vacuum pump 6.        Charging valve  7.        Solution valve   8.        Strong solution sampling valve  9.        Refrigerant spray valve  10.     Refrigerant pump  11.     Refrigerant sampling valve 12.     Refrigerant by-pass valve 13.     Control panel   14.     Heat exchanger I 15.     Heat exchanger II 16.     Condensate heat exchanger 17.     De-crystallization pipe 18.     Steam inlet 19.     Condensate outlet 20.     Absorber 21.     Evaporator 22.     Cooling water inlet 23.     Chilled water inlet 24.     Chilled water outlet 25.     Cooling water outlet 26.     Condenser 27.     Generator

    Fig. 1-1 Front view of chiller

       

  Fig. 1-2 Rear view of chiller

 

 

      

              Fig.1-3 Left and right views of chiller

Table 1-1 List of valves on the chiller

No	Description	Purpose	Group	Type
2	Upper purging valve of vacuum pump	For purging non-condensable gases from chiller, and opened during purging by vacuum pump. Opened when measuring the internal pressure in the chiller and leak testing under charged nitrogen in the chiller. NC(Normally closed).	Purging valves	Stop valves
3	Lower purging valve of vacuum pump	For purging non-condensable gases from chiller and gas cylinder, open when chiller is running, close when chiller is stop.
4	Sampling purging valve	For measuring the vacuum pump performance, and purging the external vessel (such as sampler) by vacuum pump. NC.
6	Charging valve	Used for charging and drain solution from chiller, and sampling of weak solution. NC.	Solution valves	Stop valves
8	Strong solution sampling valve	For sampling of strong solution. NC.
9	Refrigerant spray valve	To adjust spraying quantity of refrigerant water. NO (Normally open).	Refrigerant valve	Vacuum butterfly valve
11	Refrigerant sampling valve	For sampling of refrigerant and charging and drain refrigerant, and charging gas into the chiller when test the chiller under positive pressure. NC.	Refrigerant valves	Stop valves
12	Refrigerant by-pass valve	For regeneration of refrigerant or dilution solution, by-passing part of refrigerant from evaporator to absorber. NC.

Generator

Generator is the shell and tube structure, consists of cylinder, heat transfer tubes, thermal insulating layer, solution baffle and heat transfer tube bundles, etc. The working steam from boiler or external system flows through the inside of heat transfer tubes and heats LiBr solution outside of it, then generates high temperature refrigerant vapor. Meanwhile solution concentrates into strong solution. The working steam releases heat in the heat transfer tubes and become condensate, then flow into condensate heat exchanger via condensate solution packing. The pressure of the steam generator is about 7.9kPa (59mmHg).

Condenser

Condenser consists of cylinder, heat transfer tubes and end covers. Cooling water from cooling tower (about 32℃), enters heat transfer tube via end covers, to condense the vapor from generator, then cooling water left the condenser at temperature about 40℃ to the cooling tower. Produced refrigerant water flows into evaporator through U pipe throttle. A part of refrigerant water is flashed and cooled, and enters refrigerant water pan. Condenser and generator are arranged in one shell (upper shell) with identical pressure.

Evaporator

Evaporator consists of heat transfer tubes, end covers, and water distribution pan, refrigerant water pan, refrigerant water chamber and refrigerant pump. Chilled water from customer (about 12℃) enters heat transfer tubes through end covers, and evaporates refrigerant water, which is sprayed over the tubes by the refrigerant pump from water chamber. Rest of water, which had not been evaporated is collected in the water pan, and is sent to distribution tube again to evaporate. Thus produced chilled water runs from the evaporator at temperature about 7℃ into the system of customer. Pressure in the evaporator is about 0.9Kpa (6.75 mmHg).

Absorber

Absorber consists of heat transfer tubes, end covers, water distribution pan, solution chamber and solution pump. Cooling water from cooling tower (about 32℃) enters the heat transfer tubes through end covers to cool the strong solution distributed outside tubes. At a set temperature and concentration (for instance 52℃ and 64%) lithium bromide solution possesses tremendous water vapor absorbing capacity, and absorbs considerable refrigerant vapor, produced in the evaporator in the same shell, and transfers the heat to the cooling water. After absorbing water vapor, solution is diluted, and flows into the lower solution chamber, then sent to generator to be concentrated. Absorber and evaporator locate in the same shell under the identical pressure. Absorber is divided into two parts, which are arranged in both sides of evaporator.

Solution heat exchanger

Solution heat exchanger consists of two heat exchangers, which are composed of heat transfer tubes, supporting rods, front and rear end covers and headers. Weak solution flows through internal part of tubes, and strong solution pass over the tubes. Heat exchanger has the purpose of increasing the temperature of weak solution and reducing that of strong solution.

Condensate heat exchanger

Condensate heat exchanger consists of heat transfer tubes, supporting rods, front and rear end covers. Weak solution passes over the tubes and steam condensate flows through internal part of tubes. Heat exchanger has the purpose to make weak solution absorb heat of steam condensate and increase its temperature.

Purge unit

Purge unit consists of purge piping (arranged in absorber and condenser) and gas box, ejector, gas cylinder, solution return pipe, stop valves, and vacuum pump. It is functioned for purge non-condensable gas from the chiller/heater to reduce the influence of gas to the normal operation of chiller. During its operation, the non-condensable gas is extracted through purge piping to the pressure reduced area of ejector, which is created by a part of weak solution, supplied by the solution pump from absorber. Then gas flows with solution into the gas cylinder. Gas is stored in the gas cylinder and gas box, and solution returns into the absorber through solution return pipe. Stored gas can be discharged into atmosphere by vacuum pump manually or automatically, if pressure reaches setting value.

De-crystallization pipe

De-crystallization pipe: Mounted between generator and absorber, a channel for strong solution in solution heat exchanger returning to absorber directly after decrystallization. When solution heat exchanger gets crystallized, strong solution that should have went to absorber from heat exchanger can’t go for blocking, which would result in strong solution level in generator going up gradually until it’s falling down to the absorber directly through decrystallization pipe. Strong solution of high temperature which is not reducing temperature will be mixing with weak solution in absorber to make the temperature of the mix going up; the heat accumulated gradually will be used for dissolving the crystallization.

Hermetically-sealed pumps

Hermetically-sealed pumps (solution pump and refrigerant pump) are used to handling the working media in the chiller/heater. Solution pump has the purpose to send the lithium bromide weak solution from absorber to generator through heat exchanger. Concentrated strong solution in generator is returned to absorber. Refrigerant pump is used to spray refrigerant over the tubes in the evaporator by extracting refrigerant from refrigerant pan of evaporator, then refrigerant is evaporated by heat of chilled water.

Control panel

Control panel is the control center of chiller/heater. For details of control panel, see Chapter 4.

1.4 Working Fluid

1.4.1 Refrigerant

As the refrigerant of absorption chiller, water is used. For producing chilled water with 7℃ , pressure in the evaporator is only 0.9kPa (6.78 mmHg), and saturation temperature under such pressure is 5.5℃, which is the boiling point of water under such conditions. Refrigerant water is handled from the refrigerant pan of evaporator, and sprayed over the tubes in the evaporator. System water is chilled in the evaporator, which gives heat to refrigerant, and decreases temperature. In the mean time, the refrigerant water gains heat and evaporates to be refrigerant vapor.

1.4.2 Absorbent

As absorbent for the chiller, lithium bromide solution is used. It can be taken as the carrier of refrigerant water, and functions as to absorb the refrigerant vapor, produced in the evaporator by removing heat of chilled water, and carries refrigerant into generator. Weak solution is divided into strong solution and refrigerant vapor under the heat of supplied steam. Separated refrigerant vapor enters condenser to be condensed by dissipating the heat into atmosphere through cooling water. Refrigerant condensate returns into evaporator to produce cooling effect, and heat is taken away by cooling water.

The new charged solution should meet the following technical requirements:

Item	M-Series LiBr solution with Lithium Molybdate inhibitor	C-Series LiBr solution with Lithium Chromate inhibitor
Color	Colorless	Yellow
LiBr	（50.0±0.5）%	（50.0±0.5）%
LiOH	0.06~0.07 N	--
PH value	--	9.0~10.5
Li2MoO4	0.005%~0.030%	--
Li2CrO4	--	0.15%~0.25%

 Quality of lithium bromide solution influences the performance of chiller directly, so the solution, produced by the Company, must be used.

Solution in the chiller held in predetermined limits of concentration. Too high concentration and too low temperature can lead to separation of crystals from solution, known as crystallization. Severe crystallization will prevent chiller from normal operation. Solubility curve for LiBr solution can see attachment 1.

LiBr solution corrodes metal material, especially in the presence of oxygen. Corrosion takes place very quickly, and shortens the operation life of chiller, so the chiller should be kept under high vacuum conditions. In addition, proper content of lithium chromate in solution and maintaining pH within 9.0~10.5 are also essential to corrosion prevention. Measures should be taken in accordance with the recommendations, contained in the following text, when the content of lithium chromate and pH values are not in the specified limits.

LiBr solution without addition of corrosion-inhibitor is a colorless, transparent and nonpoisonous liquid. With the addition of Li₂MoO_4, it is changed to colorless, and nontoxic. With the addition of Li₂CrO_4, it is changed to light yellow, and slightly poisonous. Skin spattered with LiBr solution is itching. Make sure that LiBr solution does not directly contact with skin. Wash spattered skin with clean water.

1.5 Working Process

Working process is shown in the Fig. 1-4. The chiller is purged from non-condensable gases, and kept under high vacuum conditions.

        Fig. 1-4 Flow chart of chiller with control point

Weak solution from the absorber is pumped into the generator through heat exchanger and condensate heat exchange. It is heated by operating steam and concentrated to the strong solution, and high temperature refrigerant vapor is produced. Strong solution enters generator through heat exchanger in exchanging heat with weak solution which is passed through the tubes, and returns to absorber after cooled. Refrigerant vapor from generator enters condenser, and is condensed into refrigerant water by cooling water in condenser tubes and heat is taken away by refrigerant water. The refrigerant water flows into evaporator through U pipe and is flashed and enters evaporator refrigerant pan. Refrigerant from evaporator refrigerant pan is pumped over the evaporator tubes for the refrigeration effect, and evaporates to form vapor by absorbing heat of chilled water flowing through tubes. Produced refrigerant vapor enters absorber, and absorbed by strong solution in the absorber. Chilled water is cooled and returns to the system of customer. Strong solution is diluted by absorbing refrigerant vapor , then is transferred by solution pump to generator for concentration. Heat generated is carried to atmosphere by cooling water. This process is continued, and refrigeration effect is repeated.

     

1.6 Performance of Chiller

The chiller will operated under changed external conditions (such as air conditioning load, cooling water temperature).  The chiller performance under changed conditions are shown in Fig.1-5, 1-6, 1-7. These performance curves are given for customer’s reference, and the working conditions cannot be outside the limits given.

Conditions: Working steam pressure:  the nominal value Chilled water flow 100% Cooling water flow 100%  Scale coefficient 0.086 m2.K/kW

Fig.1-5 Relation of cooling capacity to chilled water

outlet temperature and cooling water inlet temperature

Conditions: Chilled water outlet temperature  7℃ Chilled water flow 100% Cooling water flow 100% Scale coefficient 0.086 m2.K/kW Cooling water inlet temperature (changed lineally in relation to load) 100%load 32℃ 80%load 30℃ 60%load 28℃ 40%load 26℃ 20%load 24℃

Fig.1-6 Relation of cooling capacity to steam consumption                                        

                                          

Conditions: Working steam pressure: the nominal value Chilled water outlet temperature  7℃ Chilled water flow 100%  Cooling water inlet temperature 32℃ Scale coefficient 0.086 m2.K/kW

Fig.1-7 Relation of cooling capacity to

           cooling water flow

Chapter 2 INSTALLATION OF CHILLER

2.1 Requirements to Maintenance during Installation

For chiller tested in the Company, customer should pay attention to check the chiller for its air tightness with our service engineers.

During storage and installation of chiller, customer is required to observe the vacuum conditions of chiller in accordance with the provisions of paragraph 5.1.4. Observe the vacuum conditions daily. Information about the change of reading of pressure gauge should be given to the service engineer of Company. Abnormality of chiller, observed by the service engineer of Company, should be corrected by the customer under his guidance and technical manual.

 Air leaks in the chiller, causes corrosion of internal parts, affects its operation life, and prevents it from normal operation under severe conditions.

During shipping, handling and installation, chiller should be protected from man-made damage and unauthorized operation of valves and instruments. In order to protect the chiller from leaks, the personnel is forbidden to climb the chiller by the piping and valves. Control panel, electric instrument and wiring should be protected from damage, control panel is not allowed be opened and wiring be removed by uncertified operator. Protection means from dampness and rain should be adopted.

All the outlet openings of chiller should be covered to protect it from ingression of dirty and foreign matter.

With original openings covered and protections provided, chiller should be covered by a tarpaulin, but not plastic sheeting (which will permeate damp and speed up its corrosion), when it is left in the open air. Chiller or its parts, stored for long time in the room or in the open air, should be covered carefully.

Box with bulk of parts is recommended to store at dry and safe place to ensure its intact.

2.2 Requirements to Machine Room

1.   Machine room should be designed with good ventilation and lighting facility.

2.   Temperature in the room should be kept in the limits of 5-40℃, and humidity less than 90%.

3.   Machine room should be supplied with power voltage of 380VAC±10%, and without accidental failure of power.

4.   Machine room is provided with perfect drain system. Machine room should be constructed against fire and water flood.

5.   Machine room should be arranged in such a way, that the chiller is accessible to handling, install, maintain, repair, replace the parts and modernize chiller. Space and height should be reserved for handling and transport the chiller.

6.   Minimum space with the dimensions shown in the Table2-1 should be reserved. Space for changing tubes (a little smaller than length of chiller) should be provided in axial direction from any one side of chiller. Chiller can be installed with the ends against window or door for pulling the leaking tubes.

7.   Machine room should be designed with due considerations of its vibration and noise to the surrounding rooms, and provided with good sound isolation, attenuation and vibration absorbing means.

8.   Machine room should be able to carry the total weight of whole package of chiller and its auxiliary equipment during their operation.

9.   Machine room should be equipped with locks and screens for doors and windows to protect from the entrance of unauthorized people.

10.               Machine room should be provided with tools, spare parts and materials for maintenance of chiller and systems.

Table2-1 Minimum space, reserved around the chiller

Axial direction	1.0m	Above chiller	0.2m
From control panel	1.2m	Rear side	0.8m

2.3 Installation of Chiller

The foundation for chiller should be designed to carry the chiller with operation weight. as static load, because of its stable operation and minor vibration. The foundation should be raised from the floor with dimensions in accordance with installation drawings provided by our Company. The installation work of chiller is essential to its successful operation, especially the levelness should be ensured, which is a key link to ensure performance and normal operation, though the installation of chiller is not so complicated.

In general, the chiller is installed in the machine room, but it can be installed outside, if the conditions not allowed. But, the unit cannot be installed in the open air, when the lowest circumstance temperature in the year is less than 5℃.When installed outside the room, means should be taken to protect the chiller body, control panel, measuring and control instrument, steam adjusting valve and piping valves from rain, wind, corrosion and heat dissipation.

Chiller should be installed with consideration of daily operation, and provision of space for withdraws of heat transfer tubes from any end of chiller. In the mean time, it can be installed with one end oriented to the window. Drainage should be provided around the chiller and covered with perforated plate made from cast iron.

Before positioning the chiller on the fundament, which should be cleaned from dirty, it should be kept level and with dimensions in accordance with the design requirements. On the support area of fundament, hard rubber plates with area bigger than supporting foot and thickness of about 10mm should be covered.

2.3.1          Installation Of Assembled Chiller

During installation of chiller, it should be handled carefully with steel ropes placed on the marked area. Every steel rope should have capacity to carry whole weight of chiller. Chiller should be handled with care to be protected from damage of any parts. The position of contact of ropes with the chiller should be adjusted to avoid the damage of parts, such as small diameter pipes, connecting wires and instrument. Chiller should be handled in horizontal position with slow movement in order to be protected from drop of unit owing to deviation of center of gravity, when solution in chiller is moved. Chiller should be lowered with all feet contacted with the surface of floor or fundament.

 When chiller rolls on steel pipes, distance between two pipes is less than 0.5m.

 To avoid damage of chiller, handling equipment and steel wire should have capacity to carry weight more than that of chiller. During operation personnel is not allowed to stay under the handling equipment for avoiding injuries and deaths.

After positioning of chiller on the fundament, the longitudinal and transversal levelness should be checked. Two holes on the both sides of tube plates of evaporator-absorber are provided, and should be on the same level with deviation less than 1/1000. Chiller can be raised at one end by crane or two jacks at each side of unit, and long steel spacer can be inserted between the foot and fundament,  or channel steel can be welded at the bottom of one base, and lift chiller with two lifting jacks to adjust levelness, if the levelness of unit is not in the prescribed limits.

 Deviation from prescribed levelness of installed chiller causes re-distribution of working fluid flow in the unit, and affects its normal operation under severe conditions.

2. 3.2 Installation of unit of chiller from split parts

Separation of chiller into split units impairs vacuum of chiller, and causes its corrosion. Chiller tested in the works, should not be separated into split parts.

For split chiller, its installation is basically the same as for assembled unit of chiller. The main difference is: the separated parts should be put at their own fundament, lined up for connections, checked for longitudinal and transversal levelness, and welded together, if it is separated into two parts. Or the lower shell should be put on the fundament, checked with longitudinal and transversal levelness; then the upper shell should be put on the lower shell, lined up for connection, checked for longitudinal and transversal levelness, and welded together with lower shell. Cautions should be taken to prevent the welding from ingression of slag and scales into the unit. Welded chiller should be checked again for levelness. Installed unit should be evacuated, and checked for air tightness.

2.4 Adjustment of Levelness of Chiller

Method of checking the levelness of unit usually is done by level or with transparent plastic hose and water as follows:

1.  As shown in the Figure 2-1, transparent plastic hose is hanged close to the level reference holes, and charged with water. The hose should be without knot and air bubble inside it, and cannot be flattened.

2.  Water lever in one end of hose is kept to the center of one reference hole. Water level in the another end of plastic hose should be at same height with the center of another reference hole, adjusting the height of chiller at another end by crane or other means. The longitudinal levelness of installed chiller equals to the difference of water level in two ends divided by the distance between the tube plates. Chiller is kept in the limits of levelness, which should be less than 1/1000, by insertion of long steel spacer at the lower end.

3.  The transverse levelness is adjusted in the same manner by placing the plastic hose along the tube plate.

            

       

 

 

 

 

 

2.5 Insulation of Chiller

When the chiller is installed and checked for air tightness, the following parts should be insulated:

Thermal insulation locations (~90℃): generator, heat exchanger, condensate heat exchanger , and hoses connecting them.

Cold insulation locations(~7℃): evaporator water pan, evaporator water chamber end covers, piping before and after refrigerant pump.

Thickness of thermal insulation layer: 40mm.

Thermal insulating material: rock wool felt, super-fine glass fiber felt, or material with similar property.

Thickness of cold insulation layer: 30mm.

Cold insulating material: polyethylene foam plastics, or material with similar property. Cold insulating material shall not absorb water, and no gas can be pass through. Joints shall be sealed by adhesive tapes.

Thermal/cold insulation construction: welding shall not be conducted on the chiller, electric circuits shall not be damaged and temperature-measuring tubes, valves, drainage cocks and testing components of control system shall not be covered.

Insulation parts are shown in Fig.2-2.

  

Fig.2-2 The parts of chiller to be insulated

Chapter 3 INSTALLATION OF EXTERNAL SYSTEMS

Chiller is provided with external systems, such as water system (including chilled and cooling water), working steam and condensate system and electric system, see Fig.3-1.

Fig 3-1 Diagram for external systems

3.1（Chilled and Cooling）Water System

Water piping is designed to ensure the water speed in the limits of 1.5-2.5m/s (for nominal water flow, see nameplate). Piping should be constructed with less turns or round turns. Piping is supported or hanged carefully to prevent the chiller from the load by piping. Chiller is influenced in operation life by external load or vibration, or damaged during severe conditions.

At the inlets and outlets chiller and pumps (including spare pumps) should be provided with compensators (including rubber compensators, rubber hoses, metal bellows, and metal hoses).

At the inlets of chiller and pumps the detachable filter with element of large area of 5-8 meshes/inches should be installed. Piping should be designed to clean filter and maintain the pumps without interrupting the operation of chiller.

 Detachable filters should be installed at water pump inlet and chilled water inlet of chiller to protect the heat transfer tubes from clogging by the foreign matters, to protect the chiller from degradation of performance and rupture of tubes by freezing.

Chiller and pumps (including spare pumps) should be provided with pressure gauges (or gauge common for measuring pressure at different locations by switching from location to location, if it desirable). At the inlets and outlets of chiller thermometers shall be installed. For water systems of unit, flow meters with scale covering the nominal water requirements should be installed in manner accessible for reading and maintenance.

Detachable short pipes of about 800 mm in length should be installed at chilled water inlet and outlet to remove the end cover of evaporator and clean heat transfer tubes. At the inlet of chiller the detachable filter with element of large area of 5-8 meshes should be installed. Water piping should be provided with drain valve at its lowest point, drain piping led to channel, and vent at its highest point.

Pressure setting device shall meet the requirements for constant pressure and water drainage when expansion and water makeup when leakage, if closed water system is used.

Cooling tower shall conform to the requirements of chiller in water flow and thermodynamic performance. Cooling tower with water collecting tank should be selected, if no reservoir is provided for the cooling water system. Cooling tower shall be installed at place far from source of heat and dust, especially from chimney, with good ventilation, taking consideration of noise and water drift. Regulating valve and instantaneous water flow meter should be installed at the make up and drain piping to keep the quality of cooling water. Cooling tower should be operated by thermostatic control at the outlet of cooling water from tower, or fan of tower is connected with the control system of chiller, and on/off controlled from control panel. Bypass piping with two-way or three-way valves can be connected between the inlet and outlet of tower to maintain constant temperature of cooling water, while part of cooling water is bypassed tower into chiller in case of too low temperature of cooling water.

Pump can be installed at the outlet of chiller to reduce the water pressure working on the chiller, when water system is operated under higher pressure.

 Pressure working on the water head of chiller cannot be above its maximum load carrying capability, otherwise, the chiller cannot be working normally owing to the deformation of water head.

Water treatment means should be provided to protect heat transfer tubes from corrosion or scale formation, if water cannot meet the requirements in quality.

Chiller is supplied with a flow switch, which is installed in a straight section with length not less than 10 times of pipe diameter (horizontal or vertical) of chilled water piping from the chiller. For installation of flow switch a round hole shall be done at the straight pipe (or at upside for horizontal section). Then the support of flow switch shall be welded to the hole, and switch is installed with deflector perpendicular to the flow direction. The direction marked on the meter shall be the same for the direction of water flow. Switch shall be connected with the control system of chiller. The length of straight section of pipe shall be at least 5 times of pipe diameter, as shown in Fig.3-2. It is not allowed to reduce the minimum settings, as the chiller shipped from works with minimum setting of flow.

The chilled and cooling water piping should be designed and installed with valves at the piping inlets and outlet from the chiller, and a piping with a valve bypassing the chiller is provided before the valve to the inlet of chiller and after the valve from the chiller. In order to flushing the piping, the valves at the inlets and outlets should be closed and valve on the bypassing piping opened. After the operation, the inlet and outlet valves should be opened, and valves on the bypassing piping closed.

The chiller should be drained after it tested hydraulically (or kept with water, if the commissioning is followed).

The chilled water piping should be insulated, when the chiller is installed and leak tested. 

 

 

 

 

 

 

3.2 Working Steam System

Piping is constructed with less turns or round turns, and installed in accordance with the respective standards.

Regulating valve should be arranged close to the chiller. A pressure reducer is to be installed, when the working steam pressure is higher than that of HP generator. A manual stop valve should be provided on the steam piping for shut off steam, when accidental event occurs. The manual stop valves should be installed before and after the pressure reducer and steam adjusting valve, while the bypass piping is provided to inspect and repair the reducer and regulating valves. Steam over heat is not more than 15℃.

 If steam over heat is more than 15℃, it will cause serious results, such as chiller’s damage, even generator’s write-off and personal injury, etc.

A steam/water separator should be installed, if the dryness of steam is less than 0.99. A drain valve is installed on the lowest point of piping before the steam entering the chiller. To protect the chiller from hydraulic hammer, before starting the chiller, the drain valve should be opened to flush condensate.

The chiller is thermally insulated, when it is mounted, ensuring no slackness, danger and leakage will take place.

 

3.3 System of Condensate of Working Steam

The piping of condensate of working steam should be laid down lower than the HP generator of chiller. If it is installed higher than the HP generator, then the calculation of condensate pressure, supplied by our company should be taken into consideration, and measures should be provided to prevent the back flow of condensate into tube bundles of HP generator, when the chiller is operated under low load. Drain valve is provided at the lowest point of condensate piping to avoid the hydraulic hammer in the starting stage.

A condensate tank with highest water level lower than HP generator is installed after the condensate discharge piping, when condensate is returned to the boiler house.

 System must be cleaned before it is connected to the chiller unit .otherwise chiller tube will get clogged due to the deposit in the water/steam , which will lead to chiller performance drop and serious troubles such as tube frozen .

3.4 Electric System

As power source the three phases and five lines electric system of AC 380 is used. Power lines are laid to the control panel of chiller by customer, and connected by Shuangliang engineer during commissioning (Phase and zero lines are connected to internal terminals in the control panel, and ground line is connected to the ground screw in the panel). Power lines should meet the power specifications, indicated on the nameplate of chiller.

Special grounding pole with resistance less than 10Ωshould be provided, and connected with the grounding line of chiller to ensure the its safe operation.

 Failure of special grounding pole or using zero line instead of grounding pole will cause severe damage of chiller or injury or death of personnel.

The standard supplied chiller/heater is provided with interlocked control of cooling water pump, chilled water pump (including standby ones) and fans for cooling tower so that the pumps (including standby ones) and fans for cooling tower will be started/stopped by the control system of chiller/heater. If more than one chiller/heaters share one cooling water system, electric driven valves must be set at cooling water inlets of each chiller/heater to realize interlocked function of control system. The electric distribution panel should have terminals for connecting control lines for pumps and fans. The control lines should be laid and marked by customer. For a chiller, 12 control lines of 0.75mm² should be provided. Power lines should be laid separately from control ones.

The cooling water pump and chilled water pump should be working interlocked, i.e. the cooling water pump stop first, and then the chilled water pump, if no provisions for interlocked controls are used.

 Chilled water and cooling water pumps (including standby ones) and fans for cooling tower must be interlocked with control system of chiller/heaters. At cooling water inlets of each chiller/heater, electric driven valves must be set to interlock with control system, if there are limiting conditions. Otherwise, Shuangliang will not take any responsibility for malfunction and other bad results such as rupture of tubes.

For chillers with functions of remote start, stop and monitoring, the installation of chiller will be proceeded in accordance with the “The instruction of installation and operation of remote start, stop and monitoring system”.

4.1 Configuration of System

Advanced control system MMI2 with color touch screen as man-machine interface is used, and such measuring and control elements, as PLC controller, platinum resistance, flow switch, pressure sensors, level controller are implemented to ensure the optimized control of chiller. The configuration of control system is shown in Fig.4-1.

4.2 Function of System

The control system is used in two modes: automatic and manual control. Automatic control mode is preferred, manual control is used only for commissioning and to shooting the failure of chiller.

Control system is designed for efficient and automatic control of chiller. It is provided with the functions: setting the data, automatic staring up and shut-down the unit, limit control of cooling water inlet temperature, limit control of solution concentration, automatic control of loads and circulating flow of solution, measuring and displaying the operation data in real time, safety protection, memory and storage of data and etc.

4.2.1          Normal functions

Table 4-1 Normal functions of control system

No.	Name of function	Description of function
1	Data setting	For working the chiller under expected or optimum conditions, the data, including the chilled water outlet temperature, are set by certified personnel in accordance with the local conditions.
2	Automatic start and stop of chiller	Chiller is started/stopped merely by personnel pressing the touch screen, and will be operated steadily in nominal conditions.
3	Limit control of cooling water inlet temperature (cooling mode)	Chiller will be operated steadily by limiting its capacity under low inlet temperature of cooling water (18-28℃)
4	Limit control of solution concentration	The control system will calculate the concentration of concentrated solution, crystallization and safe temperatures based upon of measured actual operating data, and adjust the operation conditions automatically, when the crystallization trends to occur.
5	Automatic adjusting the load	Cooling capacity of chiller is automatically adjusted by regulating the heat source supply in accordance with chilled water outlet temperature.
6	Automatic adjusting the circulating flow of solution	Control system will adjust the output frequency to the inverter to regulate the speed of solution pump in accordance with the measurement of lever and pressure in the HP generator, which will make the solution circulation to meet the requirements of chiller operation.
7	Measurement  and display of operation data in real time	Control system will display the operation data, such as temperatures, pressures, levels on the touch screen in real time by sensors installed, to make the operation personnel to know the chiller more easily.
8	Safety protection	Control system will protect the chiller from the dangerous operation, and take the appropriate measures automatically.
9	Failure diagnosis	Determine the failure conditions automatically on the basis of measured data, and take the appropriate protecting measures .
10	Data storage	Control system will store the operation data of last week, contents of last five failures, and contents and operation data of last three failures.
11	Information storage	Control system stores the information, such as working principle of chiller, guide of operation and maintenance, which can be used by operational personnel, while operate the touch screen.
12	Other extendible functions	The control system reserves extendible functions, such as the remote and concentrated control to meet the requirements of customer.

4.2.2          Safety Protection

Chiller will give alarm and stop operation, when it surpasses the set values. The safety protection items and set values are indicated in Table 4-2.

Table 4-2 Safety protection data

No	Item	Set value	No	Item	Set value
1	Evaporation temperature	2℃	7	Steam pressure	Nominal value +0.05MPa
2	Chilled water outlet temperature	4.5℃	8	Chilled water flow	60% of nominal value
3	Cooling water inlet temperature	18℃	9	Over current of solution pump (inverter)	100% of nominal value
4	Intermediate solution temperature	100℃	10	Over current of refrigerant pump (thermal relay)	100% of nominal value
5	De-crystallizing pipe temperature	65℃	11	Over current of vacuum pump (thermal relay)	100% of nominal value
6	Condensation temperature	48℃

 

4.3 Control Panel

                  

   

4.4 Control Flow Chart

Control flow chart describes the procedure of start and stop of elements of chiller during its start/stop. Control process is shown in Fig.4-4 “Control Flow Chart”.

                                 

 

 

 

 

 

4.5 Operation Method

4.5.1 General

Put the switch (single pole switch, normally at position ON), which is installed in the upper portion of control panel, into the position “ON”, lock the door of control panel, and put the switch at the lower portion of control panel into the position “ON”. At this moment, the power supply is connected. The signal “POWER” and “RUN” will display. Three seconds after the display of WELCOME, on the screen will show the main menu as shown on the Figure 4-5. Operator can start/stop the chiller as indicated by the menu. And also to adjust the operating parameters, or to other control, and learn the working principle, basic operation procedures and methods of maintenance. 

Fig 4-5 Main Menu

WORKING PRINCIPLE OF CHILLER Press this key, on the screen will show the flow chart of chiller/heater for refrigeration and heating, and working principle for refrigeration and heating also.

GUIDE FO OPERATION OF CHILLER Press this key, on the screen will be show the more than 10 methods of operation, such as sampling of refrigerant water, charge of solution, inspection of chiller/heater for air-tightness.

HISTORY OF OPERATION Press this key, on the screen will show the last three troubles and the operation data during week.

CONTROL MODE Press this key to select the mode of operation (Auto or Manual, the chiller/heater cannot be changed to manual operation, while the unit is operated under AUTO control).

MONITORING OF CHILLER Press this key, the screen will show the figure of monitoring, which is dependent to the control mode. Operator can operate the chiller/heater, solution, refrigerant and vacuum pumps, and set the data, such as outlet temperature of chilled water. The current information on the different parts of chiller/heater can be shown also.

SETTING OF PARAMETER Press this key the adjustable data, such as the outlet temperature of chilled water can be set, and diminish the deviation of displayed value and actual value of operation data.

GUIDE TO MAINTENANCE Press this key the screen will show the contents and methods of maintenance.

1)  The screen protection function is provided, which will stop display (blacken), if no operations of screen occurred during 1h. For this period the control function of chiller is maintained, and the screen will continue work, if it is touched lightly.

2)  The screen can be cleaned by soft wet rag, no volatile solvent (such as benzene) can be used.

3)  Internally set values and positions of external toggle switches are fixed in the factory, and not allowed are changed by customer.

4.5.2 Operation Mode and Control Selection

The Graph of Operation Mode selection can be selected by pressing the Key OPERATION MODE SELECTION of main menu, or pressing the Key MENU to have display the menu graph, then to select operation mode by pressing the appropriate key. On the Graph of OPERATION MODE there are two operation modes (refrigeration and heating), and two types of control (Auto and Manual). You can select the operation mode and control type, and then to press the key “CONFIRMATION” to get the appropriate chiller operation monitoring graph.

4.5.3 Data Setting

The Data setting graph can be selected by pressing the Key DATA SETTING of main menu on the touch screen, or by pressing the Key MENU on the right upper angle of screen. In later case, touch screen will display menu graph, then to select Data setting graph by pressing the appropriate key, when the screen is displaying other graph. There are two kinds of data can be set, namely the regulating data setting and setting of deviation for displayed data.

4.5.3.1Regulating Data Setting

The regulating data should be changed, while the chiller will be operated on the new conditions. Regulating data include set values for chilled water outlet temperature, cooling water inlet temperature, pressure in HP generator, and appropriate P I D values. P I D values should be set by certified personnel.

 Set values of data should be approved by certified personnel from Shuangliang Service Company. The set values of regulating data cannot be over its limiting value, and not too far from the nominal operation conditions to prevent the chiller from abnormal operation.

There will be regulating data display graph by pressing the key of setting of regulating data under the data setting graph. Pressing the key of Password for data setting, input the correct password on numerical keyboard, and press the key “Enter” to have the graph of setting data. At this time, the data can be changed. The graph remains unchanged, while the password is erroneous. The input deviation will be cleaned by pressing the key CLR on the numerical keyboard.

During changing the data, touch screen will display numerical keyboard by pressing the push-button on the left side of data to be changed. The data will be changed by input new values and pressing the key of confirmation. The setting of data is finished by pressing the key “OFF” on the numerical keyboard.

4.5.3.2 Setting of Deviation for Displayed Data

The deviation between the value measured by calibrated standard instruments and displayed value on the touch screen can be removed by changing the set deviation of displayed data. For example, the value of chilled water outlet temperature measured by calibrated thermometer is 7℃, and displayed value of this temperature is 6.5℃, then the deviation of displayed data should be increased by 0.5℃ on the basis of set deviation. Changing of set deviation is similar to that of changing of set value of operation data.

During changing the data, touch screen will display numerical keyboard by pressing the push-button on the left side of data to be changed. The data will be changed by input new values and pressing the key CONFIRMATION. The data are set by pressing the key “OFF” on the numerical keyboard.

4.5.3.3 solution pump inverter frequency setting

Factory setting: lower limit for condensation temp 27℃ , inverter frequency 25HZ; upper limit 45℃, inverter frequency is 40Hz.

4.5.4 Operation of Chiller

4.5.4.1 Start/stop of Vacuum Pump

Vacuum pump can be started or stopped at any time. But before attempting to start vacuum pump, it should be checked for oil level, and operated in accordance of paragraph 6.8 of Chapter 6 Management of vacuum pump.

The graph of chiller monitoring is displayed by pressing the key CHILLER MONITORING of main menu; or pressing key MENU on the upper right angle to display the content of main menu, then pressing the key CHILLER MONITORING to display the graph of chiller monitoring, when touch screen displays other graph; or to display the graph of chiller monitoring after selecting the operation conditions.

Purge is realized by pressing key VACUUM PUMP START to start the vacuum pump, then open the lower purging valve and related purge valves. Before shutdown of vacuum pump, close lower and upper purging valves then press the key VACUUM PUMP STOP.

 The lower purging valve of vacuum pump should be closed, before the vacuum pump is to be stopped.

4.5.4.2    Start/Stop of Solution and Refrigerant Pump

Solution and refrigerant pumps are started and stopped automatically, when the automatic operation mode is selected. The only work to be done by the operational personnel is to start and stop chiller in accordance with the following procedure.

Solution and refrigerant pumps should be started or stopped by the operational personnel in the following procedure manually, when the manual control mode is selected:

The graph of chiller monitoring is displayed by pressing the key CHILLER MONITORING of main menu; or pressing key MENU on the upper right angle to display the content of main menu, then pressing the key CHILLER MONITORING to display the graph of chiller monitoring, when touch screen displays other graph; or to enter the operation monitoring by selecting the mode of operation and control during the chiller shut down. Solution and refrigerant pumps can be started or stopped by pressing the keys SOLUTION PUMP START, REFRIGERANT PUMP START, or SOLUTION PUMP STOP, REFRIGERANT PUMP STOP.

1)  Before startup of solution pump, it is essential to ensure that solution has been charged.

2)  Prior to startup of refrigerant pump, strong solution concentration shown on touch screen should be ensured above 56% and chilled water system is to be checked to protect heat transfer tubes from freezing.

3)  During manual control the solution pump is not allowed to be operated by manually operating inverter, and should be controlled by the control system according to the solution level and temperature.

 

4.5.4.3    Start/Stop of Chiller

The chiller monitoring graph is displayed by the operation mode selection and data setting in 4.5.2 and 4.5.3. Graph of trouble monitoring will be displayed by pressing key TROUBLE MONITORING. The following operations can be done, when the chiller trouble-free indicating red LED lights (except failure of chilled water)

A.     Automatic Control

In graph of CHILLER MONITORING press key SYSTEM START, and press “CONFIRM” key shown in next graph, then operator can run chiller following procedure displayed on touch screen to start chilled water pump, cooling water pump. Until receives reflection of both starting signal of chilled water and cooling water pump and chilled water flow signal, chiller is not ready to be started, then should press key CONFIRM COMPLETED to start chiller finally, in the meanwhile touch screen shows graph of CHILLER MONITORING.

The chilled water pump is to be started with its outlet valve closed. Then the outlet valve is opened step by step to get the nominal flow rate. When chilled water pump and cooling water pump are interlocked, their start and stop operation is controlled by chiller, no need of personal operation.

Chiller is stopped by pressing the key SYSTEM STOP on the graph of chiller operation monitoring. Following this operation, the chiller will be operated with automatic dilution, after reach set terms chiller will stop. Procedure of stopping cooling water pump and chilled water pump refers to Fig 4-4 Control flow chart.

B.      Manual Control

Under Manual Control mode, functions of interlocking with external system and safety protection still are workable. Start chiller in the same way adopted under Auto Control mode. Until receives reflection of both starting signal of chilled water and cooling water pump and chilled water flow signal, chiller is not ready to be started. Then should press key CONFIRM COMPLETED to start chiller finally.

1) The solution pump is started and solution circulation is controlled automatically by pressing the key SOLUTION PUMP START. 2) Steam adjusting valve will be opened by pressing the key STEAM ADJUSTING VALVE OPEN. The opening of steam adjusting valve will be increased by 5% for every pressing of the key. 3) Based on the requirements, Press REFRIGERANT PUMP START or REFRIGERANT PUMP STOP to start or stop refrigerant pump. But refrigerant pump cannot be started if strong solution concentration is less than 56%.

When stop chiller, press keys of REFRIGERANT PUMP STOP and HOT WATER ADJUSTING VALVE CLOSE to stop refrigerant pump and close steam adjusting valve (The manual steam regulating valve is closed manually). Then stop fan of cooling tower, 3 minutes later close cooling water pump outlet valve slowly and stop pump. When displayed concentration of solution is lower than 56%, press key SYSTEM STOP to stop solution pump, then close chilled water pump outlet valve slowly and stop pump.

4.5.4.4    Operation Monitoring of Chiller

The operation conditions of parts and chiller and content of trouble, if any, can be displayed to the operational personnel by the graph of chiller operation monitoring.

4.5.4.5    Trouble Shooting

The chiller will give alarm and stop operation automatically, when trouble occurs. The alarm bell will be silent, and trouble content graph will be displayed upon pressing the key TROUBLE MONITORING by the operational personnel. The content of trouble will be shown (by the red light before the trouble). The cause of this trouble and method of shooting will be given by pressing the key TROUBLE FUNCTION. The TROUBLE MONITORING will be returned, when the return key is pressed.

Chapter 5 COMMISSIONING OF CHILLER

5.1 Preparing to Commissioning

Chiller shall be commissioned by Shuangliang authorized engineer with the assistance of customer

5.1.1 Inspection of Exteriors and Installation Engineering

1.Check chiller for absence of severe vibration and shock, painting, cracking of hermetically sealed pumps, damage and deformation of control panel, inverter, instrument, valves and cables, check chiller raining damage or exposition to the open air for long time. Recover chiller, if there are damages or deviations.

2.Check the installation, which should meet the requirements.

5.1.2 Inspection of External Conditions

5.1.2.1 Inspection of Chilled and Cooling Water Piping

1)   Check piping system for cleanness, cooling tower, pond and outlet connections for foreign matters.

2)   Check piping system for drain and vent at the lowest and highest points of piping respectively.

3)   Check the system for filter.

4)   Check the piping system again the drawing. Check the piping for the correct direction and position, piping system for its hanging, supporting to avoid the transmission of load to the end covers of water boxes.

5)   Check water systems for leakage, pumps and piping for vibration, flow rate to meet the requirements. Install water treatment means, if poor water quality.

6)   Check the piping system for thermometers, thermostats, flow switches, temperature sensors, and pressure gages for their correct installation positions.

7)   Check pumps for: a. Absence slackness of bolt connections; b. adequate amount of lubricating oil and grease; c. leakage of water through sealing. It should be not form continuous line of water; d. Check the correct operation electric current; E. Check the pump for normal pressure, noise and motor temperature.

8)   Check cooling tower for its correct type, water flow and reasonable temperature difference; Check fan for its correct operation and electric current.

5.1.2.2    Inspection of Steam Piping

Inspect according to the provisions of 3.2.

5.1.2.3    Inspection of Working Steam Condensate Piping 

Inspect according to the provisions of 3.3.

Check the manual stop valve for opening, when it is installed in the steam condensate piping. It is kept opened during operation.

5.1.3 Inspection of Vacuum Pump

1)  Check vacuum pump oil for its correct type; check vacuum pump oil for its appearance, oil will be emulsified, if it contains water.

2)  Check vacuum pump for its correct rotation. Ensure the low purge valve of vacuum pump is closed. Remove the plug from the sampling and purge valve, and cover the valve opening by finger. Put the vacuum pump into operation. The pump is operated in the correct direction, if air is socked through the valve opening. Change the motor cable connections, if it is rotated in the wrong direction.

5.1.4 Inspection of Chiller for Air Tightness

The chiller has been tested for air tightness strictly before shipping. However, leakage is likely to occur at some locations due to vibration and impact during transportation handling, and installation. Chiller should be rechecked for air tightness prior to starting the commissioning first under vacuum, and then under pressure, if the former is not satisfactory. The inspection of air tightness is repeated to get the satisfactory results.

5.1.4.1 Leakage Detection under Vacuum

1) Close all valves, which are exposed to atmosphere. The chiller is evacuated by vacuum pump to a pressure below 30Pa, if it is no tested in factory. Stop the vacuum pump, record local ambient temperature t1 and read the absolute pressure p1 by McLeod gage. Record ambient temperature t2 and absolute pressure p2 in chiller after 24h. Calculate the pressure increase ( ) in the chiller by the following formula, and shall not exceed 5Pa:

2) Chiller, which had been tested in the factory, shall be tested for air-tightness by the air bubbles, that a rubber or plastic hose shall be connected with the discharge opening of vacuum pump at one end, and inserted about 50mm clean water into the vacuum oil in a vessel at the another end. Close sampling valve, start vacuum pump then close ballast valve of vacuum pump, and count the number of bubbles per minute from water when numbers of bubbles become stable. Open upper purge valve of vacuum pump and lower purge valve of vacuum pump and observe the bubble numbers. If the number is big, chiller needs to be made vacuum. Count again when bubble numbers become less. And if the bubbles number difference when purging valve open and close are less than 3, close upper and lower purging valves and stop vacuum pump. If it cannot reach the normal numbers after 2 hours and keeps in a rather big number, the chiller should be checked for leakage by positive nitrogen gas pressure.

5.1.4.2 Leakage Detection under Pressure

The chiller is charged with nitrogen (for LiBr solution charged chiller only nitrogen is used) to the pressure of 0.08MPa or dry oil free compressed air, and possible locations of leakage for welds, valves, flange seals, etc is covered by soap solution. Leakage takes place while bubbling. Then vent nitrogen from chiller and repair by welding. After that, the chiller is rechecked under vacuum as mentioned earlier.

Gas is charged and vented normally by refrigerant sampling valve (refrigerant is bypassed, then gas charged), or other valves, which communicate with atmosphere, if chiller is not filled with solution and refrigerant.

 Before filling gas the purge valve of condenser and upper purge valve of vacuum pump shall be opened.

5.1.5 Inspection of Control Elements and Electric Equipment

During transportation and installation of chiller the control elements and electric equipment is easy to be damaged. So after installation, the chiller is to be checked for its completeness by the personnel of Shuangliang Service Co.

1)      Inspection of Field Wiring

Check the power and interlocking wiring of power source and its equipment (such as cooling tower, pumps, and etc.)

2)      Inspection of Chiller Control

Inspect the control panel for its intactness, and correct wiring, data setting and installation of sensors and flow switch.

5.1.6 Charging of Solution

LiBr solution is supplied with (0.20±0.05)% of lithium chromate or(0.015±0.005)% of lithium molybdate as corrosion inhibitor. pH value for LiBr solution mixed with lithium chromate has been adjusted to 9-10.5, and concentration of (50±0.5)%. Alkalinity for LiBr solution mixed with lithium molybdenum has been adjusted to 0.01N~0.2N, and concentration of (50±0.5)%. These data should be reconfirmed before their charging into the chiller.

Solution is charged under negative pressure through solution charging valve at the discharge side of solution pump. Before solution is charged, the weak solution regulating valve and intermediate solution valve is opened. Evacuate the chiller down to absolute pressure in the chiller is lower than 100 Pa (or to the water vapor saturation pressure, equivalent to the ambient temperature, if the chiller is charged with solution or water). Then, as shown in Fig. 5-1, connect the vacuum or reinforced rubber hose to the connection of solution charging valve with vacuum grease from one end, and hose is filled with solution. Emerge the hose into a vessel with solution of 0.6m3 from another end. Open the solution charging valve and solution will be suck into the chiller. Keep the end of hose under the solution surface in the vessel constantly, and adjust the valve opening to a normal flow rate of solution.

Solution is charged in two portions. First charge solution about half the required amount. Then the solution-charging valve is closed and operate the solution pump to transfer solution into the generator. Stop the solution pump, when the solution pump makes noise of evacuation. Then charge the rest solution.

After charging of solution, start the vacuum pump to purge the chiller.

 Solution is charged manually. But solution pump cannot be controlled by the inverter under the manual mode, but controlled by the control system. Before starting the solution pump, the vacuum pump shall be checked for correct rotation.

5.1.7 Charging of Ethanol

Ethanol with content of about 0.3% (weight) of solution is charged in the similar manner as solution.

5.2 Commissioning of Chiller

 The chiller should be commissioned by Shuangliang authorized engineers on manual mode.

Site commissioning should be according to the actual situation, adjust LiBr solution quantity of cycling and refrigerant water quantity. Check and adjust auto control and safety protection instrument, after those series adjustments, chiller can run with high efficiency in operating state.

Commissioning Procedure

1)  Switch on air breaker on chiller control panel and check control system power supply.

2)  Press button of “Control Mode” and choose “Manual Control” and then press “Chiller monitoring” to enter operation monitoring graph.

3)  Press the button of “Start vacuum pump” to start vacuum pump and confirm its attainable limiting vacuum. Then Open lower and upper purging valves to evacuate chiller.

4)  Start chilled water pump and open chilled water pump outlet valve slowly. Then adjust chilled water flowrate (or pressure difference) to its rated value and reconfirm the function of chilled water failure protection.

5)  Start cooling water pump and open cooling water pump outlet valve slowly. Then adjust cooling water flowrate (or pressure difference) to its rated value

6)  Open the manual valve in steam inlet pipe and drain all the condensate water .

7)  Press buttons of “Start System”, “Confirm” and “Reconfirm” to start system. Control mode is “Manual”.

8)  Press button of “Start solution pump” to start solution pump when the pump will run at 27Hz.observe after 10minutes whether the solution level in generator is stabilized at the middle of sightglass. If yes, there is no need to change inverter setting .if the solution level merges the sightglass, the minimum frequency of the inverter shall be reduced. Each time reduce 1HZ till the solution level is stabilized in the middle of the sightglass.

9)  Press button of “Steam adjusting valve open”. The valve will be opened by 5% for each pressing of the key. The openness of the valve shall be increased slowly .When closing the valve, press button of “Steam adjusting valve close” and the valve will be closed by 5% for each pressing of the key.

10)               When the concentration of strong solution reaches 56%, press the button of “Start refrigerant pump”, slowly adjust the refrigerant valve.

11)               When chiller is at full load, Observe whether the liquid level in generator is at 1/3～1/2 of the sightglass. If not, adjust the inverter frequency setting if necessary.

12)               Check if refrigerant is contaminated or not, .method sees Chapter 6.5 “refrigerant water management”. When chiller reach rated cooling capacity and refrigerant water is not contaminated, and the concentration difference between weak solution and strong solution is around 5%, commissioning work complete.

13)               Chiller stop. Press “modulating valve close” button and “stop refrigerant pump” button. Then close steam inlet manual valve, stop cooling tower fan. After 3minutes slowly close cooling water exit valve and stop pump. When the concentration is shown lower than 56%, press “system stop” button or “solution pump stop” button, then close chilled water outlet valve and stop chilled water pump. Finally switch off the power supply for control box and system.

Caution:

1)      There shall be enough refrigerant water in the refrigerant tank otherwise the pump will get damaged due to empty rotation. If the pump empty rotation happens frequently, SL engineer shall help to find out the reason .With his permission, distilled water may be added inside.

2)      In case ambient temperature is lower than 20℃ and chiller stop over 8 hours, all the refrigerant water shall be bypassed from evaporator to absorber.

Chapter 6  OPERATION OF CHILLER

6.1 Safety Protection Rules

1.    In the machine room, the “Operation Procedure of Steam Operated single effect Lithium Bromide Absorption chiller”, issued by Shuangliang Co., should be hung.

2.    For machine room the strict rules of management and shift relief had to be formulated. Unauthorized person is not permitted enter the room, and touch the safety devices. The chiller cannot be operated independently by the personnel not trained by the Shuangliang Co.

3.    The steam operated single effect chiller with steam pressure greater than or equal to 0.1MPa, the HP generator belongs to the first class pressure vessel, and should be operated, maintained and checked periodically in accordance with the “Rules of safe operation and supervisory of pressure vessels” and other provisions.

4.    The chiller should be confirmed to be without any leakage, which would influence the life cycle of chiller. The chiller is considered with leakage, if its working under cooling mode is dependent on the running of vacuum pump. Then the chiller should be checked for air tightness with nitrogen charged. The chiller should be maintained with periodically change of sealing elements by the ones of same type or same material and with correct exchange method.

5.    The rust spots, especially spots on the welding connections, should be cleaned and painted, if the rust occurs, otherwise the rust will cause the leakage. The machine room should be protected from explosion by keeping the electric elements far from the paint, and the chiller is not working, when it is painted. No corrosive, explosive and poisonous gas is permitted in the machine room.

6.    The safety devices are not allowed to be set over the permitted limits. The chiller cannot be started in case of potential trouble with the safety devices. The chiller should be operated without any trouble.

7.    The chiller is shipped from manufacturer with the chilled water flow for the flow switch set to the minimum allowed value. It is strictly forbidden to decrease the set value of flow switch. It is strictly forbidden to start the chiller with the chilled water flow switch in trouble. The chiller is forbidden to operate with the vibrating piping.

8.    It is not allowed to first shutdown the chilled water pump, and then the cooling water pump.

9.    The chilled water pump and air conditioning units should be stop only when the chiller is in standstill.

10.Only the specified power supply should be used, and prohibit to touch the switch, wire and elements in the control box to avoid electric shock. The power should be cut off after the chiller stops its operation.

11.Electric motors and elements cannot be get wet to keep them running safely.

12.The operation of chiller is forbidden with control panel opened.

13.The operation of chiller is protected from scald the operational personnel by keeping them from touching the high temperature parts, such as the HP generator, heat exchanger and its associated piping.

14.The chiller should be checked and maintained strictly with the provisions of chapter 8 “Maintenance and Service”

15.Lithium bromide solution is not poisonous, but irritant when it is mixed with octanol. The machine room should be kept with good ventilation. The place dripped with solution should be washed immediately.

16.The machine room should be kept with temperature in the limits of 5-40℃, and relative humidity less than 90%.

17.Before operation of vacuum pump, the oil trap should be drained to be empty by opening the screw at the bottom of oil trap.

18.The battery for PLC and touch screen should be changed periodically (once for 2 years). Change of battery should be finished in 5 minutes. For PLC, the battery should be changed in the interval of 7 days of total standstill conditions of PCL to avoid loss of program, if the ERR indicator on CPU is light, but the chiller can be operated further. For touch screen, the battery should be changed in the interval of 5 days of total standstill conditions of touch screen to avoid loss of program, if the POWER light turns red, but the chiller can be operated further.

6.2 Procedure of Operation

6.2.1 Procedure of Starting

1.       The air breaker in the control panel is closed, and on the graph of “TROUBLE MONITORING” the NO TROUBLE indicator lights (except the trouble of failure of chilled water), and the graph can be switched to the “CHILLER MONITORING”.

2.       The chilled water pump is started when the valve on the chilled water pump outlet is closed, and then to open the valve slowly to adjust the flow or pressure drop to the nominal value.

3.       The cooling water pump is started when the valve on the cooling water pump outlet is closed, and then to open the valve slowly to adjust the flow or pressure drop to the nominal value.

4.       Open the steam valve, when the condensate drained.

5.       Press the key “SYSTEM START”, then the key “CONFIRMATION”, and finally the key “RECONFIRMATION” on the “CHILLER MONITORING”, to put the chiller into the operation condition.

6.       Start the fan of cooling tower, and adjust the cooling water flow to control the cooling water outlet temperature in the limits of 36-38℃.

7.       Check the chiller operation periodically, and take records every 2h.

 To decrease the flow rate of cooling water in case low cooling water temperature or running at low load conditions.

6.2.2          Procedure of shutdown

1.       Close the steam inlet valve, and press the key “SYSTEM STOP”, and chiller will be put into operation of dilution.

2.       Stop refrigerant water pump automatically when detected concentration reaches 58%.

3.       When detected concentration reaches 56%, automatically stop solution pump with time-log of 5 minutes.

4.       Cut the power supply from the control panel.

1.   All refrigerant water should be bypassed from evaporator to the absorber during shutdown, when the ambient temperature is less than 20℃, and the chiller will stand longer than 8h.

2.   The chiller is operated normally, when the safety device is checked periodically and its normal working is guaranteed.

3.   Check the chiller in accordance with the provisions of this technical manual.

6.3 Operation Observation and Inspection

In order to ensure the normal operation of chiller constantly, observation of chiller is required during its operation. All abnormalities should be debugged to avoid their potential risk occurs.

6.3.1          Observation of solution level

1)      Observe the generator solution level constantly, the over-high level and over low level which will harm to the chiller or even damage. If the high level or low level happens constantly, please analyze the reason.

2)      Check the solution pump and refrigerant pump is idle sound, if yes, please analyze the reason and resolve it.

6.3.2          Observation of chilled water outlet temperature

The chilled water outlet temperature should be checked constantly. The cause should be fund, if the chilled water outlet temperature rises, and it is not the influence of ambient conditions. The causes for poor performance of chiller, such as the poor air tightness, the presence of non-condensable gases, contaminated refrigerant water, crystallization of solution, less surfactant additive (ethanol), scale formation on tubes, crack on the separator plates in the water boxes and so on, should be closely analyzed.

6.3.3          Observation of cooling water

The cooling water outlet temperature from the chiller should be measured, and controlled in the limits of 38-40℃ by means of starting or stop the fan for cooing tower, adjusting the bypass water valve or water flow.

Cooling water should be carefully controlled for its pressure and temperature difference in the inlet and outlet during operation. Analyze the cause, if they changed greatly. If no significant changes for other parameters, Chances are that heat transfer tubes have been scaled or blocked, or cooling water cover clapboard gasket is broken etc.

6.3.4          Observation of de-crystallization pipe

The de-crystallization pipe should be touched by the operational personnel to test is it hot. In normal conditions, the piping end, which is close to the absorber, can be touched by hand for a long time period. If this end can be touched, but not for long time, which means there is some solution flows through crystallization pipe, this cause would be checked. This cause should be removed, if this is the mark of potential crystallization. De-crystallizing measures should be taken, if it is very hot, and there is potential crystallization on the strong solution side.

6.3.5          Inspection of vacuum condition of chiller

The conditions should be analyzed, if the vacuum pump evacuates non-condensable gas constantly. If the cause cannot be determined, then the air tightness of chiller should be checked. The heat transfer tube may be burst, or abnormal leakage occurs, if the pressure inside chiller is increased considerably. In this case the chiller should be stopped immediately, and chilled water and cooling water system should be checked, and the chilled and cooling water system to be isolated from the chiller, and the air tightness should be checked.

6.3.6          Inspection of noise and amperage of running hermetically sealed pumps

Contact with Shuangliang Service Company to analyze the cause, if abnormal noise and amperage is fund.

6.3.7          Adjusting the deviation of displayed values

Check if there is deviation in the displayed value with the actual value, and reset, if the deviation occurs.

6.3.8          Other observations

1.  Checking vacuum pump for absence of emulsification and dirty.

2.  Checking the water pumps for absence of vibration and motors for overheating.

6.4 Purge Operation

Vacuum is vital for normal operation of chiller. The vacuum (the quantity of non-condensable gas) 

1. Upper purging valve     2.Lower purging valve 3. Sampling purging valve  4. Joint 1 5. Solenoid valve 1        6. Joint 2 7. Pressure sensor 1        8. Clamp 9. Solenoid valve 2        10.Vacumm pump 11. Gas cylinder connection pipe 12. Pressure sensor 2 13. Purging box           14. Auto purging unit 15. Auto exhausting pipe    16. Oil trap 17. Oil drain plug          18.Tighten bolt

of chiller determines the operation performance and the life cycle of chiller. The purge units are provided to improve the vacuum keeping capacity of chiller. As shown in Fig.6-1, purge unit is operated automatically and manually. Purge is carried out with the sampling purge valves and pressure measuring valve is closed, and other valves operated in the following manner.

Fig. 6-1 Purging system

6.4.1          The purge of new chiller or chiller after service and maintenance

The new chiller or chiller just after maintenance, which has the internal pressure higher than the atmospheric pressure, should be vented to the atmosphere through pressure sampling valve until the internal pressure is equal to atmospheric. The chiller can be vented to atmosphere through other valves, if there is no LiBr solution and water in it. Press VACUUM SYSTEM button on chiller operation monitoring interface (as shown in Fig 6-2), press MANUAL button on vacuum system interface (as shown in Fig 6-3), then press START VACUUM PUMP button to purging vacuum. Details are shown as below,

1) Confirm that refrigerant sampling valve, charging valve and strong solution sampling valve and other valves which open into atmosphere are closed；2) Measure the limited purge capacity of vacuum pump；3) Close sampling purge valve when meet the requirements, and fully open upper purge valve of vacuum pump, then open slowly lower purge valve of vacuum pump to purge, then fully open lower purge valve of vacuum pump to purge when vacuum increases in chiller；4) If there is no solution in chiller, purge pressure less than 100Pa in chiller, then close upper purge valve of vacuum pump and lower valve of vacuum pump, and stop pump；5) If there is solution in chiller and purge when chiller stops, a rubber or plastic hose shall be connected with exhaust outlet of vacuum pump, and be inserted about 50mm into clean water in a open top vessel at another end, close sampling valve, start vacuum pump then close ballast valve of vacuum pump, and count the number of bubbles per minute from water when numbers of bubbles become stable. Open upper purge valve of vacuum pump and lower purge valve of vacuum pump and observe the bubble numbers. If the number is big, chiller needs to make vacuum. Counting again when bubble numbers decrease. And if the bubble number difference when purging valve open and close is less than 3, close purging valves and stop vacuum pump. If chiller is running, close the upper purging valve, and keep lower purging valve open; if chiller is stop, close upper and lower purging valve.

Evacuate the chiller in the same manner, when the chiller is purged not for the first time, and the vacuum is not as fair as normal.    

                                 Fig 6-2

                                Fig 6-3

6.4.2          The purge of chiller during normal operation

During the operation of chiller, usually the automatic purge unit is operating. Non-condensable gases will be purged and stored in the gas cylinder. Control system will start vacuum pump according to gas cylinder pressure automatically.

Press VACUUM SYSTEM button on chiller operation monitoring interface, press AUTO button on vacuum system interface, close upper purging valve and open lower purging valve. Control system will start vacuum pump and open solenoid valves according to gas cylinder pressure automatically.

6.4.3          Trouble Shooting

When problem happens about solenoid valves, close lower purging valve. If solenoid valve 1 gets problem, loose joint 1 and 2, loose Oil drain plug and Tighten bolt. After fixing, tight joint 1 and 2, and then tight Oil drain plug and Tighten bolt. If solenoid valve 2 gets problem, loose the joint which is connected with solenoid valve 2, after fixing, tight the joint which is connected with solenoid valve 2.

During replacing solenoid valves, pay attention to the direction of solenoid valves: arrow on solenoid 1 lead to up side, arrow on solenoid 2 leads to Oil trap.

1.   During purge operation, the lower and upper purge valves of vacuum pump shall be opened slowly to protect the vacuum pump from spraying of oil or other failure due to high evacuation rate.

2.    During purge operation the ballast valve for vacuum pump should be opened, to avoid the emulsification of oil. Emulsified white oil for vacuum pump should be changed in time.

3.   The oil trap shall be thoroughly drained in predetermined period.

4.   If solution is purged out from vacuum pump, solenoid valve shell, spool and O ring should be washed ,and drain out the solution inside vacuum pump, wash vacuum pump by clean water. Fill in new vacuum pump oil after cleaning.

6.5 Management of Refrigerant Water

During operation of chiller the LiBr solution droplets from generator may be carried into the refrigerant water into the condenser or evaporator by the refrigerant vapor. The refrigerant is contaminated, if it contains LiBr. The chiller performance will be degraded with the contamination of refrigerant water, and even had to be shutdown, when a lot of LiBr is carried into the refrigerant. So the refrigerant density should be measured periodically during operation of chiller. Refrigerant needs to be regenerated, when it contaminated.

6.5.1 Sampling and measuring the refrigerant water

Fig 6-2 Refrigerant sampling

1)  As shown in Fig. 6-2, the sampler is connected to the sampling purge valve of purge system by vacuum rubber hose with the connections covered by vacuum grease.

2)  Start vacuum pump and open the sampling purge valve to evacuate the sampler for 1-3 min.

3)  Open the sampling valve for refrigerant water; it will flow into the sampler.

4)  When appropriate quantity of refrigerant water is taken, close the refrigerant sampling valve, then close the sampling purge valve, and last stop the vacuum pump.

5)  Pour refrigerant water out of sampler into a 250mL cylinder, and measure the relative density of refrigerant water by hydrometer with scale of 1.0-1.1.

 Sampling and density measuring of refrigerant is preferred to use the sampler and cylinder, which is not used for solution. Or the sampler and cylinder had to be washed by clean water and no drop of water is left, when the same sampler and cylinder is used for both refrigerant and solution. Sampled refrigerant water should be placed separately.

6.5.2          Regeneration of refrigerant water

The regeneration of refrigerant is carried out, when the chiller is operating.

The refrigerant is to be regenerated, while it is contaminated to density of 1.04g/ml. In this case, the chiller is operated with part opening of bypass valve, i.e. the chiller is working for refrigeration and regeneration of refrigerant water at the same time. The refrigerant bypass valve is closed, while the cavitation of pump operation occurs. The process is repeated to the normal density (1.002g/ml) of refrigerant water.

6.6 Management of Lithium Bromide Solution

Lithium bromide solution is corrosive to the construction material of absorption chiller. For protection of chiller from corrosion, the solution should be added with inhibitor, and controlled in the limits of 9-10.5 for its pH value. Contamination of solution with products of corrosion will cause clogging of holes in distributor of absorber, and the lubricating and cooling piping for the pumps, which will bring influence to the operation performance and life cycle of absorption chiller. So the solution should be sampled and measured periodically during the operation of chiller, and measures should be taken to treat the solution in accordance with the results of measures. The weak solution is sampled normally, and strong solution is sampled only when its concentration is measured.

6.6.1          Sampling of LiBr solution

Sampling of solution is carried out for weak and strong solution in the similar way as for the refrigerant water. The solution sample is taken from the charging valve at the discharge side of solution pump and the sampling valve at the solution distribution box located at the bottom of shell of chiller.

The weak solution sample is taken with the sealing plug removed from the charging valve, and the Rubber hose connection, which is delivered with the chiller, shall be installed. The connection shall be removed, when the solution sample had been taken. Then the sealing plug shall be installed to ensure the secondary sealing of valve.

6.6.2          Inspection of LiBr solution

6.6.2.1    Inspection of concentration of solution

Pour the solution in the 250mL cylinder. Measure the concentration of solution by Baume hydrometer. The concentration of solution can be determined by the graph (as per attached graph 2) with the measured temperature and specific gravity, measured thermometer and hydrometer respectively. Contact with Shuangliang Co., if solution concentration is considerably different in comparison with the primary measured value.

6.6.2.2 Visual inspection

The solution quality i.e. the foreign matter and consumption of inhibitor can also be determined visually by the color of solution. The visual inspection will be carried out after sampling by several hours. The inspection results should be compared with the Table 6-1. The final results shall be given by Shuangliang Service Co.

ITEM	M-Series LiBr solution		C-Series LiBr solution
	Condition	Result	Condition	Result
COLOR	Gray Black	Corrosion happened inhibitor is consumed. A lot of ferric oxide is in the solution, and inhibitor consumed.	Light yellow Colorless Black Green	A lot of inhibitor is consumed. Inhibitor consumed considerably. A lot of ferric oxide is in the solution, and inhibitor consumed. The corrosion product copper oxide is in the solution
FLOATING MATTER	Very few Rust scale	No problem A lot of ferric oxide	Very few Rust scale	No problem A lot of ferric oxide
PRECIPITATE MATTER	Considerable	A lot of ferric oxide	Considerable	A lot of ferric oxide

Table 6-1 Visual control

6.6.3          pH value

In order to control the corrosion in the chiller, the pH value should be controlled in the limits of 9-10.5. The solution with pH value not in these limits should be adjusted. The solution is shipped from factory with the pH value in the above limits. With the operation of chiller, the pH value will be increased. The pH value of solution should be checked periodically by universal pH value test paper, and the results should be recorded. If the pH value is too high, hydrobromic acid (HBr) may be added; if it is too low, lithium hydroxide (LiOH) may be added.

The hydrobromic acid and lithium hydroxide shall be suitably diluted prior to their additions to the chiller, and with appropriate rate. They can be added in such a way: take a part of solution and pour it in a vessel, then add the lithium hydroxide or hydrobromic acid, which is diluted with 6 times of pure water. They should be mixed evenly.

The adjustment of pH value and addition of this matter is rather complex, and is preferred under the instruction of qualified engineer from Shuangliang Service Co. 

6.6.4          Inhibitor

In order to control the corrosion of LiBr solution to the chiller, the solution is added with inhibitor (Lithium Bromide (0.20±0.05) % or Lithium Molybdate (0.015±0.005) %). In the process of operation, especially in the beginning period, the inhibitor is consumed rather rapidly. The Content of inhibitor in the solution should be checked periodically by the special laboratory. The inhibitor content should be kept in the set limits, when its content is out the limits.

The quantity of inhibitor should be calculated according to the analysis of solution. Inhibitor should be added through refrigerant water sampling valve during chiller is running, then fully open the refrigerant water bypass valve to bypass all refrigerant water with inhibitor to solution. After charging inhibitor, keep chiller running at least 3 hours to make sure inhibitor is completely mixed with solution.

The addition of inhibitor is rather complex, and is preferred under the instruction of qualified engineer from Shuangliang Co. 

6.6.5          Ethanol

Ethanol is used to improve the chiller performance. The content of ethanol in the solution is 0.3%. Ethanol should be added, when the content in the solution is lower than this value. The inadequate ethanol can be determined by two ways: the one is the chiller performance is deteriorated; the second is absence of irritant odor from the solution, or no irritant odor from the vacuum pump discharge.

Ethanol is added in the similar way as for solution through the charging valve or sampling valve under negative pressure.

6.6.6          Maintenance of solution

Maintenance should be done if contents of solution changed. It should be done based on analysis by Shuangliang

6.6.7          Transferring of solution between the chiller and solution tank

During maintenance of chiller, the solution is transferred from chiller in following way: Firstly, the tank, in which the solution is transferred, should be kept under high vacuum condition; Secondly, during transferring the solution, the pressure difference is preferred be made by introducing nitrogen. If in the worth case the air is used instead, then the chiller should be purged immediately, when the transferring is finished.

6.6.7.1 Transfer of Solution to Chiller 

 

1) Shown as Fig. 6-3, connect chiller with solution stored tank by vacuum rubber hose. (Air in the hose should be exhausted discharged)

The solution tank is charged by nitrogen under the pressure of 0.02~0.04Mpa at gas inlet valve. Fig.6-3 Transfer of Solution to between Chiller and Solution Stored Tank

3) Open the solution inlet/outlet valve in the solution tank and the charging valve in chiller. The solution will flow into the chiller automatically. The transfer of solution process has three steps, which are just the same as 5.1.6.

4）After finish charging solution, start up vacuum pump to purge promptly.

6.6.7.2 Solution Transfer from Chiller to Solution Stored Tank 

1) Shown as Fig.6-3, connect chiller with solution tank by vacuum rubber hose. (Air in the hose should be discharged)

2) Open the charging valve of chiller and the solution inlet/outlet valve in the solution stored tank, then start up solution pump to pump solution into solution stored tank until the cavitation and stop.

3) If solution pump is damaged and cannot start up, charge nitrogen with the pressure of 0.02~0.04 Mpa to extrude the solution in chiller.

4) After finish and pass the operation on detecting leakage, start up vacuum pump promptly to purge vacuum. Detect leakage again if need.

6.7 Management of Water Quality

6.7.1 Management of cooling water

During operation of chiller, cooling water outlet temperature is preferred be kept in the limits of 38-40℃. Cooling water temperature can be regulated by variation of speed of pump motor, or by changing the opening of valve on the bypass pipe between the water inlet and outlet of cooling tower.

During operation of chiller, cooling water should be sampled and analyzed. The quality of cooling and makeup water should meet the requirements of Table 6-2. Water should be treated, if it cannot meet the requirements.

Contamination of cooling water (bad quality) not only causes scale formation in heat transfer tubes, influences heat exchange efficiency and reduces the performance of chiller, but also corrodes heat transfer tubes and leads to major failure of chiller.

6.7.2          Management of Chilled Water

Chilled water system can be opened or closed type. Soft water is preferred, if closed system is adopted. For opened chilled water system, it is managed as for the cooling water system.

Table 6-2 Water quality standard

Item		Unit	Makeup water	Cooling water	Tendency
					Corrosion	Scaling
Basic	pH value(25℃)		6.0~8.0	6.5~8.0	○	○
	electric conductivity(25℃)		<200	<800	○	○
	chloric ion Cl-	mg Cl-/L	<50	<200	○
	sulfuric acid radical ion	mg /L	<50	<200	○
	acid consumption rate(pH4.8)	mg CaCO3/L	<50	<100		○
	Total hardness	mg CaCO3/L	<50	<200		○
Reference	Iron Fe	mg Fe/L	<0.3	<1.0	○	○
	sulfuric ion S2-	mg S2-/L	undetectable	undetectable	○
	ammoniac ion	mg /L	<0.2	<1.0	○
	silicon dioxide SiO2	mg SiO2/L	<30	<50		○

6.8 Operation of Vacuum Pump

Vacuum pump is vital equipment to keep the chiller under vacuum condition. It is important to ensure the reliability of vacuum pump. The vacuum pump should be maintained in the following manner. For more information, see Operation manual of vacuum pump.

1.   Before the primary startup of vacuum pump, it should be test started for very short period to determine whether the direction of rotation of pump meets the indicated direction. This can be determined also by the gas, discharged from the pump outlet. The checking of pump rotation can be done after the vacuum pump oil is charged.

2.   Vacuum pump oil is charged or changed while the pump is shutdown to avoid the damage of pump and splashing of oil.

3.   The vacuum pump should be start/stop repeatedly for short time to avoid damage the pump by the loading from direct starting, if it is under long-term shutdown.

4.   To reduce the emulsification of oil, vacuum pump should be operated under opened ballast valve.

5.   For long time evacuation and avoiding the oil emulsification, the vacuum pump should be operated idly to warming up, then open the purge valve. Before shutdown the vacuum pump, it also needs to work idly for a while to discharge the water vapor, which mixed with the oil.

6.   The vacuum pump oil should be checked constantly for oil level and preventing the oil emulsification. The oil level should in the middle of sight glass, and drain the emulsified oil or water drops by screwing out the plug on the bottom of oil box, if the oil is milk white. Then appropriate amount of oil should be added. Oil should be changed and washed, if it is too dirty.

7.   If solution is purged out from vacuum pump, solenoid valve shell, spool and O ring should be washed ,and drain out the solution inside vacuum pump, wash vacuum pump by clean water. Fill in new vacuum pump oil after cleaning.

8.   Vacuum pump should be checked for its attainable limiting vacuum in the following. (1) Remove the sealing plug from the purge valve, and connect Macleod gauge to the sampling purge valve with vacuum grease by means of rubber hose. (2) Take off the sealing plate from the oil trap and rubber hose connection from vacuum pump, connect the vacuum pump with oil trap. (3) Run vacuum pump for 3 min, then open slowly sampling purge valve and measure the pressure by Macleod gauge. Vacuum pump is satisfactory, if the pressure is less than 30 Pa. Otherwise, the vacuum pump shall be checked till satisfactory results are obtained.

9.   The vacuum pump should be removed from the chiller while it is stop running for a long period as follows: 1) Close the upper and lower purging valves of vacuum pump;2) Take off the sealing ring (or rubber tube) of at the end of sampling purging valve, and open the sampling purging valve;3) Remove the metallic hose connected between the oil trap and vacuum pump;4) Install the sealing plate shipped with the chiller at the lower part of oil trap to stop the function of trap;5)Install the rubber hose connection piece shipped with the chiller at the suction of vacuum pump, and connect the rubber hose DN10 covered by vacuum grease with the sampling purging valve; 6) Start the vacuum pump to evacuate the non-condensable gas from the trap, and close the sampling purging valve and stop the vacuum pump after 10 min of its running; 7) Remove the rubber hose from the purging valve and plug it.

Note：Please kindly note item 8 and 9 should be operated by Shuangliang service engineers.

6.9 Description of Operation of Valves

6.9.1          Method of Operation The Valve

Here followed the methods of opening and closing the valve, and changing the sealing ring, valve plug and others. The working principle and description of construction of valve are included in the “Operation Instruction of Welded Special Valves”. For the application of torque wrench, see its operation.

1) Method of Opening The Valve

1) Remove the upper hood, check and tighten the press-cup (turn the press-cup in anti-clockwise for tightening).

1)Turn the valve stem in anti-clockwise by wrench to open the valve.

2)Install the press-cup on place with the Loctite at the threads, and tighten the hood. 

    

2) Method of Closing The Valve

1)  Remove the upper hood.

2)  Adjust the setting value of torque wrench to the permitted torque for the valve.

3)  Turn the valve stem in clockwise by wrench to close the valve.

4)  Check and tighten the press-cup (turn the press-cup in anti-clockwise for tightening).

5)  Install the press-cup on place with the Loctite at the threads, and tighten the hood. 

Note:

1. For the purging, charging, refrigerant probe, concentrated solution probe and pressure measuring valves, which led to the atmosphere, block is inserted into the valve. Operate these valves after taking out the block, and insert the block on the Loctite after operation.

2. For probing the weak solution through the charging valve, after the block had been taken away, the valve outlet should be connected with intermediate part supplied with the chiller, and then operate. After the probe had been taken, remove the intermediate part, and install the block on the Loctite.   

3)  Method of Changing The Sealing Ring or Valve Plug

1)  Remove the upper hood.

2)  Turn clockwise the press-cup to remove it. (Loosen the fitting screw, if it is provided.)

3)  Take out the valve stem from the valve body, and change the O-ring or under part of stem (with valve plug).

4)  Install the valve stem into the valve body with the O-rings covered with vacuum grease.

5)  Tighten the press-cup anti-clockwise, and turn the valve stem by torque wrench to adjust the valve by closing and opening it.

6)  Install the press-cup on place with the Loctite at the threads, and tighten the hood. 

3)Troubleshootings

No	Trouble	Cause	Measure
1	The valve stem cannot be turned.	Seizing of upper driving thread of valve stem	Remove press-cup, take out valve stem, repair the driving thread. Change the valve stem, if the thread cannot be repaired.
2	Leaking of sealing	Scratch at the surface of valve plug	Change the under part of valve stem (with the valve plug).
		Damage at the hole surface of scratch at the sealing surface.	Change the valve.
3	Leaking of O-ring	Damage or aging of O-ring	Change O-ring.

6.9.2          The Operation of Torque Wrench

The FDN 100 type torque wrench is used with overall length of 380mm, torque limits of 20-100Nm, torque tolerance of ±4%. The overall view of torque wrench is shown on the Fig.6-4.

Fig. 6-4 Torque wrench

1)  Allowable torque limits for the valve stem

Allowable torque limits for the valve stem is 40Nm for type DN10/I; 40Nm for type DN10/II; and 70Nm for type DN25. 

2)  Preset torque

Turn the handle, the dial disk will be revolved accordingly, stop at the place, where the required torque is at the red division on the dial disk. Then fix the torque by turning the rear cover in the direction of arrow to stop.  

3)  Force applying

Apply the wrench with preset torque to the valve stem, turn it in the direction “¯” smoothly. The valve is closed, when “click” sound is taken place, or the hand feeling became different than before. The operation is finished at this moment. Stop applying force, and keep the original position of wrench.

4)  Storing

After the operation, the torque setting should be restored to the minimum value for store the wrench.

5)  Note:

1.The wrench can be applied only in the direction of “¯”.

2.Never use the wrench over the allowable torque.

3.Never disassemble the wrench by yourself.

6.10 Safety guidance for operation

1）   Control system of chiller shall be interlocked with that of chilled water pump and cooling water pump to be started and stopped.

2）   When design and install external chilled water and cooling water pipelines, the valve should be installed before chiller inlet and outlet, and one bypass pipe between valve before chiller inlet and valve after chiller outlet, parallel to chiller with valve, when clean pipeline after finished installation of all pipe system, close valves of chiller inlet/outlet, open valve of bypass pipe, make clean water flow through bypass pipe. After finish cleaning, drain out water, close valve of bypass pipe, open valves of chiller inlet/outlet.

3）   The chiller and all pump inlet should install with filter following the operation manual, otherwise, if dirty in water enter into chiller and jam the heat exchanger, which may degrade chiller’s performance, or even result in tubes being frost cracked or other severe damage.

4）   Before installation, the transportation rack shall be removed, and then put the chiller on foundation. If the rack did not removed, it should cut off the angle iron or wedge weld on rack to fix both ends of heat exchanger. For some models, one angle of heat exchanger is welded on rack, the other end is fixed with evaporator-absorber body shell, which only this steel angle should removed.

5）   When charge or transfer solution, it shall do best to reduce loss of solution, after operation, it shall flush solution sprayed on ground and chiller body by water to clean them. For area of chiller body paint has been damaged, it should be painted immediately.

Chapter 7 TROUBLESHOOTING

7.1 Shutdown of Chiller/heater due to Troubles

During operation of chiller/heater, control system will check the running conditions of different parts of chiller to judge if chiller is running in normal conditions. The control system will automatically solve the 3 type troubles shown below. For troubleshooting process, see Fig.4-4.

1) If any below abnormal phenomena occurs, chiller will be unloaded firstly. If chiller system still does not turn well after 10-minute unloading, control system will alarm immediately and automatic shut down chiller after turning into dilution operation.  

(1)  High condenser temperature;

(2)  Low cooling water temperature;

(3)  High de-crystallization pipe temperature;

(4)  High steam pressure;

(5)  High generator solution temperature

2) When overcurrent of refrigerant water pump occurs, chiller will alarm immediately and shut down after turning into dilution operation. When overcurrent of vacuum pump occurs, chiller will alarm immediately. When cylinder gas pressure reaches set valve, a graph will appear automatically on the graph of operation monitoring on the touch screen showing “High pressure in chiller auto-purging unit, please start vacuum pump”. The operator may start purge according to methods introduced in “6.4 Purge Operation”.

3) When any following severe trouble occurs, chiller will alarm instantly and shut down emergently.

(1)    Low chilled water temperature

(2)    Failure of chilled water

(3)    Low refrigerant water temperature;

(4)    Trouble in inverter;

During automatic shutdown of chiller/heater, the operator should press key “TROUBLE MONITORING” on the graph of operation monitoring on the touch screen to make the alarm silent and search for the cause of trouble and its shooting. Operator should remove the cause of trouble immediately after the trouble occurs, and then start again the chiller/heater.

7.2 Common Troubles and Their Shooting

7.2.1 Troubleshooting for chiller

Table 7-1 Common Troubles and Their Shooting for Chiller

No	Trouble	Cause	Troubleshooting
1	No power display of control system.	1)  No power to control panel. 2)  Switch for control power supply is OFF	1)    Check main power supply and air breaker 2)    Put the control switch and main air breaker ON.
2	Poor vacuum	1)  Leakage in chiller. 2)  Poor performance of vacuum pump and trouble in purge system	1)    Leak test and remove the leakage. 2)    Check the vacuum pump for performance, and remove the trouble in the purge system.
3	Chilled water temperature difference is less than nominal value.	1)  Cooling capacity is less than designed value. 2)  Chilled water flow is greater than nominal value. 3)  Displayed temperature is not correct.	1)  See No.6. 2)  Reduce the flow accordingly. 3)  Correct the display deviation.
4	High chilled water outlet temperature	1)  Cooling capacity is less than designed value. 2)  Too great outside load. 3)  Set value is too high	1)  See No.6 2)  Reduce cooling load accordingly. 3)  Set the nominal value.
5	Contaminated refrigerant water	1)   High solution cycling, high solution level. 2)   Too big solution charge 3)   Low cooling water temperature. 4)   Too high chilled water outlet temperature. 5)   Too much heat supply. 6)   Poor quality of solution.	1)        Adjust solution pump transformer frequency properly. 2)        Drain part of solution. 3)        Regulate cooling water bypass valve; check controller of cooling water inlet temperature. 4)        See No. 4 5)        Regulate heat supply. 6)        Sampling solution, and analyze, change solution with more reliable quality.
6	Cooling capacity is lower than design value.(cooling mode)	1)  Poor vacuum 2)  High cooling water inlet temperature. 3)  Less cooling water flow. 4)  Scale or clogging of heat transfer tubes by foreign matter 5)  Inadequate heat supply. 6)  Refrigerant water contaminated. 7)  Too much or too less refrigerant water spraying quantity. 8)  Too much refrigerant water 9)  Inadequate Ethanol in solution. 10)               Less charge of solution. 11)               Solution cycling capacity is not enough. 12)               Low chilled water outlet temperature. 13)               The less cooling load from the user	1)  See No.2 2)  Regulate cooling water bypass valve; check the controller for cooling water inlet temperature, check cooling tower and its fan. 3)  Check the valve opening and filter cleanness in the cooling water system, check the cooling water pump. 4)  Clean heat transfer tubes. 5)  Increase heat supply. 6)  Sampling refrigerant water, and regenerate it, if density is greater than 1.04. 7)  Close refrigerant water bypass valve, little close or open the spray valve. 8)  Drain refrigerant water. 9)  Add ethanol. 10)               Charge appropriate amount of solution. 11)               Adjust solution pump transformer frequency to ensure solution cycling meet the requirement. 12)               Cooling capacity will be reduced with the reduction of chilled water outlet temperature. Set the nominal chilled water outlet temperature. 13)               Normal situation during auto control
7	Crystallization during startup	1)   Air leakage or a lot amount of non-condensable gas in chiller. 2)   Too low cooling water inlet temperature. 3)   Overloaded.	1)    Purge chiller by vacuum pump. 2)    Regulate cooling water bypass valve to increase temperature. Check controller of cooling water inlet temperature. 3)    Increase load slowly for startup.
8	Crystallization during shutdown	Inadequate dilution	Check the set value for dilution and actual situation.
9	Crystallization during operation	1)       Non-condensable gas in chiller. 2)       Too less of solution cycling 3)       Too big heat supply.	1)    Purge chiller by vacuum pump. 2)    Increase solution pump inverter frequency. 3)    Reduce heat supply.
10	Sudden shutdown during operation	1)    Failure of power supply or loss of phase line. 2)    Safety protection system works. a.  Abnormal refrigerant pump. b.  Abnormal solution pump c.  High temperature of crystallization pipe. d.  High temperature of generator solution e.  Failure of chilled water f.   Failure of cooling water. g.  Other trouble	1)      Check power supply to restore it. 2)      Remove the cause of troubles, and restore the normal operation: a.      If overload relay works, reposition and check motor temperature, amperage and insulation. b.     As per above item a. c.     Chiller de-crystallization as per item 7、8、9. d.     See No.11. e.      See No.14 f.      See No.15. g.     Investigate the trouble cause and remove it by pressing “Trouble Monitoring” at the operation screen
11	High generator temperature.	1)    Poor air tightness and air leakage 2)    Heat input is greater than nominal value. 3)    High cooling water temperature or low cooling water flow. 4)    Severe scale on the cooling waterside of heat transfer tubes. 5)    Minor cycling solution	1)       Purge the chiller by vacuum pump and remove the leakage. 2)       Regulate heat input. 3)       Regulate cooling water bypass valve, check cooling tower and fan, or regulate cooling water flow. 4)       Clean heat transfer tubes. 5)       Increase solution pump inverter frequency.
12	Cavitation of solution pump	1)  Inadequate solution charged. 2)  Crystallization.	1)  Charge solution. 2)  De-crystallization.
13	Cavitation of refrigerant pump	1)  Inadequate refrigerant water. 2)  Low refrigerant water temperature.	1)  Add refrigerant water. 2)  Regulate cooling water temperature or add refrigerant water.
14	Failure of chilled water	1)  Damaged pump (or motor). 2)  Inadequate refrigerant water is added.	1)     Repair or startup standby pump. 2)     Regulate the cooling water temperature or add refrigerant water.
15	Failure of cooling water	1)    Same as failure of chilled water. 2)    Less water is stored in the cooling tower.	1)  Same as for failure of chilled water. 2)  Addition of water storing capacity (for water collecting type cooling tower)
16	Abnormal decrease of cooling capacity,  chiller pressure in  in the auto purge unit equal or above the atmospheric pressure	The heat transfer tubes leak or other parts leak abnormally.	Urgent measures should be taken: 1)   Cut the power to shutdown the chiller. 2)   Close valve and stop the chilled and cooling water pumps. 3)   Drain the chiller. 4)   Transfer solution from chiller to tank; open the end covers to test the air tightness.
17	Decrease the vacuum during shutdown period	Leakage	Test chiller for air tightness.
18	Big variations of values displayed on the touch screen(MMI2)	1)  Poor grounding. 2)  Poor sensors for temperature and etc. 3)  Troubles in touch screen.	1)  Re-grounding. 2)  Repair or replace. 3)  Replace.
19	Pump not operated.	1)        Pump motor overload protected. 2)        Troubles in the control circuit. 3)        Trouble in pump itself. 4)        Automatic protection of chiller works.	1)   Find the cause of overload and reset. 2)   Check the circuit. 3)   Replace. 4)   Find the cause.
20	Buzzer not working.	1)  Buzzer damaged. 2)  Fuse blown.	1)  Replace. 2)  Replace.

7.2.2 Troubleshooting for Electrical System

Table 7.2.2 Troubleshooting for Electrical System

No	Trouble	Measure
1	No power supply for control system	1.    Check the availability of power to the chiller. 2.    Check the air breaker of the control panel to the power at its input and output sides. 3.    Check the single-pole switch of control loop for the control panel to the power at its input and output sides. 4.    Check the power supply of control elements and apparatus in accordance with the electrical principal circuit.
2	Trouble of control elements and apparatus	1.  Check the normal input of control elements and apparatus. Check the normal conditions of three phase and control power supplies for contactors. Check the power supply and electrode circuit of level controller. 2.  Check the output of control elements and apparatus, for instance the output of three-phase power supply, the output signals of high and low level output signals of level controller. 3.  Check other control circuits, such as the control signal from the PLC to the controllers, and etc. 4.  Check the function of elements and apparatus in accordance with their instructions.
3	Trouble of touch screen	1.Check the fixing of communication and power lines. Check the batteries of touch panel (which should be changed every 2 years). 2.Check the touch panel according to the troubleshooting instruction.
4	Trouble of PLC (ERROR light up)	1.Check the elements and apparatus step by step, including the PLC controller, the power supply of controller, the input/output modules, base plate and PLC batteries (for every two years). 2.Check the PLC according to the operation instruction.
5	Trouble of external measuring elements	1.Check the fixing of connection lines and the situation of circuits (Connect new lines from sensors to the control panel, and measure the output of sensors). 2.Check the sensors (reconnect sensor to control box, and test sensor output is normal or not.) 3.Check the installation situation of sensors (such as the blockage of pressure sensing hole for pressure sensors, and the damage of target plates of flow switches).
6	Trouble of external actuating elements	1.Check the correct connection of circuits and control signal. 2.Check the actuating elements according to the instruction.

7.3 Solution Crystallization and Its Treatment

7.3.1 Crystallization during startup of chiller

Solution in the heat exchanger from the strong solution side and in the generator may be crystallized as the low cooling temperature and non-condensable gas exists in the chiller during its startup period. The measures for de-crystallization are as follows:

1)   The de-crystallization measures are similar as operation period see Chapter 7.3.2, if the crystallization of solution occurs in the heat exchanger.

2)   When solution in generator is crystallized, then the generator is supplied with minor heat from regulating valve to raise the temperature of solution. For speeding up the de-crystallization, shell of generator can be heated by steam from outside. The solution pump is started, when the solution is de-crystallized, and the chiller can be put into operation, when all solution in the chiller is even mixed.

3)   De-crystallize the generator at first, and then the heat exchanger, if the generator and heat exchanger is crystallized in the same time.

7.3.2          Crystallization during Operation

The place prone to crystallize during chiller operation is the strong solution side of heat exchanger and the strong solution outlet. Hot de-crystallization pipe is the outstanding mark of solution crystallization. But hot de-crystallization pipe also can be caused by the poor circulation rate of solution. In general, if the hot de-crystallization pipe is caused by crystallization, then the weak solution temperature at the outlet of heat exchanger and the surface temperature of heat exchanger will go down. The measures for de-crystallization are as follows:

1)  Change the control of chiller to manual mode, and re-start the chiller by minor opening of steam adjusting valve.

2)  Stop the supply of cooling water to raise the temperature of weak solution to about 60℃, but not above 70℃.Shut the chilled water, when its outlet temperature is higher than inlet temperature.

3)      Open the refrigerant bypass valve slowly to bypass part of refrigerant to absorber to dilute the solution and not lower the solution level in the absorber considerably. The solution will de-crystallize, if the chiller is operated under such conditions continuously.

4)      Heat the crystallized parts by steam or condensate, if they are difficult to be de-crystallized in short time.

5)      Put the chiller into operation, when it is de-crystallized. The purge piping is also to be de-crystallized, if it had been crystallized also.

6)      Find the cause of crystallization, and appropriate measures are taken.

The chiller is normal, if the de-crystallization pipe is not hot even under the full load of chiller.

7.3.3          Crystallization during Shutdown

During shutdown the solution is crystallized, if it is not adequately diluted during shutdown, or the cooling water temperature is low. The solution pump cannot work for solution crystallization. It can be de-crystallized by heating the pump casing and its inlet and outlet by steam to run the pump. The caution should be taken to avoid the steam and its condensate into the motor and its control means. No direct heating of motor is permitted.

7.4 Freezing of Refrigerant Water

Refrigerant water is frozen by low chilled water outlet temperature or small flow, or failures in the safety protection means. So, the safety protection should be inspected and calibrated periodically, or the chilled water system should be checked and cleaned.

For de-freezing the refrigerant water, the cooling tower fan should be stopped, the cooling water flow should be reduced, and the chiller is put into operation in the normal manner. If the refrigerant water still is frozen, then close the steam adjusting valve and solution pump.

7.5 Treatment of Emergency

7.5.1  Fire and earthquake

Cut the power supply, close all the valves, and take fire protection measures.

7.5.2          Water flooding

Remove the control panel and vacuum pump, and handle them to safe place. All the hermetically sealed pumps, sensors and electric wires should be covered by plastic films to be protected from water leakage.

7.5.3          Freezing or cracking of heat transfer tubes (abrupt reducing of cooling capacity, and abnormal rising of pressure in the chiller)

Stop chiller operation (stop immediately the refrigerant and solution pumps), stop the chilled water and cooling water pumps after shutoff their valves, and transfer the solution from chiller to the tank. Drain water from the chiller, check the chiller for air tightness and change the broken tubes by opening the end covers.

7.5.4          Chiller shutdown due to failure

Analyze the reason of failure, and restart the chiller after trouble shooting.

7.5.5          Failure of Power Supply

When the power supply is failed, close the steam manual valve, then close the valves at the discharge of cooling and chilled water pumps and stop the pumps. If before the power failed, the sampling or purge process was taken place, then the sampling valve and lower and upper purge valves should be closed.

7.5.5.1    Treatment for Short Period (less Than 1h) Failure of Power Supply

In general the solution is not tend to be crystallized, if the power supplied is failed only for limited time, and solution remains hot. In such case, the chiller can be put into operation, as the power supply recovered.

1)  If the chilled and cooling water pumps had been shut as the power failed, then these pumps are to be started by confirming that the valves at their discharge had been closed. Then these valves opened and adjusted to the flow required.

2)  Control the chiller manually, start the solution and refrigerant pumps, and stop the chiller with dilution operation.

3)  Control the chiller automatically, start it in the normal procedure.

4)  Check the refrigerant water for its density; regenerate it, if its value is above 1.04.

7.5.5.2    Treatment for Long Period (more than 1h) Failure of Power Supply

The crystallization of solution tends to occur, if the chiller is shutdown for long period under high solution concentration. Operate the chiller in the following ways, when the power recovered:

1)      Start the chiller manually for operation with dilution as above mentioned for short shutdown.

2)      Operate the chiller under light load for 30 min in trial manner, Stop the chiller for de-crystallization, if the temperature of de-crystallization pipe is increased. If no crystallization occurs, then stop the chiller, and re-start the chiller in automatic mode.

3)      Check the refrigerant water for its density after de-crystallization; regenerate it, if its value is above 1.04.

7.6 Trouble of Vacuum pump

Troubles, causes and their solutions are listed in Table 7-3.

Table 7-3 Normal troubles and their solutions for vacuum pump

No	Trouble	Cause	Solution
1	Low limit vacuum	1)         Oil cannot seals the discharge valve, noisy discharge, as the oil level is low. 2)         Not correct type of oil is used. 3)         Oil emulsified. 4)         Leakage in the oil trap and its piping. 5)         Broken spring for revolving plate. 6)         Clogged oil holes lower the vacuum. 7)         Worn and torn the revolving plates and stator. 8)         Rubber components for suction pipe and ballast valve not assembled correctly, broken or aged. 9)         Vacuum system, including piping, contaminated severely.	1)  Add oil to the level in the limits of 5mm under middle line. 2)  Change to correct type vacuum pump oil. 3)  Drain the emulsified oil or water droplets from the drain plug on the bottom of oil box, and add oil; change oil, if it is too dirty. 4)  Check for tightness, and remove leakage. 5)  Change to new spring. 6)  Drain the oil, remove the oil box, lose the press plate of oil nozzle, and withdraw the oil nozzle and clean the oil holes. The components are cleaned, not using gauze as far as possible. 7)  Check, repair and replace. 8)  Adjust and change. 9)  Clean.
2	Oil spray	1)  Too high oil level. 2)  No oil or oil contaminated in oil separator. 3)  Lost or assembled not correctly the oil trapping plate.	1)  Drain oil to normal level. 2)  Check, clean and repair. 3)  Check and re-assemble.
3	Oil leakage	1)    Broken oil drain plug and gasket. 2)    Broken or assembled not correctly the gasket for oil box cover. 3)    Deformed thermally the plexiglass. 4)    Lost spring for oil seal. 5)    Not closed the ballast valve during shutdown of pump. 6)    Oil seal is worn due to error assembling.	1)  Check and replace. 2)  Check, adjust or replace. 3)  Replace and lower the oil temperature. 4)  Check and repair. 5)  Close it while shutdown the pump. 6)  Reassemble or replace.
4	Noise	1)       Broken the springs for revolving plates, and increased oil supply. 2)       Worn bearings. 3)       Broken parts.	1)  Check and replace. 2)  Check, adjust and replace, when it is necessary. 3) Check and replace.
5	Back flow of oil	1)   Assembled not correct or worn the oil seal in the pump cover. 2)   Not normal the surface of pump cover and stator. 3)   Broken the discharge valve plate	1)  Replace. 2)  Check and repair. 3)  Replace.

7.7 Troubles of Hermetically Sealed Pump

Troubles, causes and their solutions are listed as follows:

1)  Cavitation of pump

Cause and solution see Table 7-1.

2)  Bearings worn.

a.  The rotating parts of pump are not balanced dynamically. Check and repair rotating parts.

b.  Cavitation in pump. Check and solve the problem.

c.  Foreign matters in solution. Re-generate solution, check and clean filter.

d.  Pump flow is not in the appropriate limits, and axial load is increased. Adjust the pump flow in the designed limits.

3)  Amperage of pump motor is increased.

a.   The internal resistance of pump is increased. Open and check the pump casing, impeller and inducer. Remove the roughness of surface by sandpaper or other mechanical means.

b.  Abnormal contact in bearings. Check and replace the bearing, sleeves and thrust plate. Remove the cause for increased friction.

c.  Abnormal contact between the rotor and stator. Check the surface for abnormalities of expansion deformation. Remove the cause for abnormal wear.

d.  Poor contact between the impeller and casing of pump. Check the assembly of pump shaft and impeller and deflection of shaft. Adjust or replace the shaft, if it is out of normal limits.

e.   Foreign matter in the pump casing. Disassemble the pump casing to remove the foreign matter.

f.   Reduced motor insulation resistance and unbalance of resistance of coil for three phases. Restore, or otherwise, replace the stator. Dry the motor slowly by torch, if it is damped.

g.  Motor operates under absence of any phase current. Check the fixing of wire connection of motor. Tighten it, if it is slack.

h.  The voltage and frequency of power supply is fluctuating. Check the power supply line.

4)  Thermal relay protection is working frequently

a.  Pump motor overloaded and overheated. Check the flow and temperature of working medium. Check and clean filter.

b.  Trouble in thermal relay. Check and replace the thermal relay.

5)  Pump noisy and vibrated severely

a.   Reversed rotation of pump. Change the connection of leads to pump motor to correct rotation direction.

b.  Too great or small pump flow. Check the pump operation to make the operation of pump in the determined limits.

c.  Cavitation in pump. See Table 7-1.

d.  Foreign matter in pump. Check and remove foreign matter from pump.

e.   Contact of casing with the impeller or inducer. Check and repair.

f.   The fixing of bolts is slack. Check and repair pump.

g.  Unbalanced rotor of pump. Check and balance pump dynamically.

Chapter 8 MAINTENANCE OF CHILLER

The performance of chiller and its life cycle is dependent not only upon the starting commissioning, but also the maintenance of chiller. The maintenance of chiller is not so complex, but it had to be done vary carefully. Chiller should be maintained periodically to operate it reliably, prevent it from accidents and to increase its life. Violation of following maintenance precautions causes the unnecessary loss.

1)      The Hermetically Sealed Pump, stop valve, pipeline valve, motorized valve, auto replacement etc components of chiller are for Shuangliang’s exclusive use. Shuangliang exclusive spare are required for chiller maintenance and repair.

2)      Chiller should be maintained by qualified maintenance personnel from Shuangliang Service Co. Before the service is carried out, the power should be cut from the control panel. It is forbidden to do the maintenance and repair under the power is supplied to prevent the injuries and deaths of people from the electric shock. During the handling and moving the chiller, the specialized instrument should be used.

 

8.1 Periodical Inspection

8.1.1 Monthly inspection

During operation of chiller, it is inspected monthly following the Table 8-1.

Table 8-1 Items for monthly inspection

No	Group	Item	Content
1	Chilled water	pH value and inhibitor in chilled water	Sampling and measuring chilled water, adjust it, if it is out the limits.
2	Cooling water	Cooling water quality	Analyzing the water quality, and treat it based upon the results.
3	External systems	1)  Clean filter. 2)  Chilled and cooling water pumps 3)  Cooling tower.	1)        Remove filters from external systems, and clean them. 2)        Inspect, repair and change oil, tighten the screw connections, especially the fundament bolts. 3)        Clean the tower from dirty, check fans for slackness and drop of driving belts, correct them, if abnormality is found.
4	Control and safety protection elements	Reliability of working	Check the control and safety protection elements for their working reliability. Check the insulation between level sounding electrodes, and between the shell and electrodes for short circuit.

8.1.2          Yearly Inspection

Before the startup and shutdown in a yearly season, the following inspections should be checked.

Table 8-2 Items for yearly inspection

No	Group	Item	Content	Time
1	Chiller	1)    Clean heat transfer tubes. 2)    Inspect chiller for air tightness 3)    Painting	1)    Open the end covers of water boxes for chilled and cooling water, clean tubes and end covers by brushes or chemical detergent, and replace the gaskets. 2)    Check the chiller for air tightness by the procedure illustrated in paragraph 5.1.4 of chapter 5. 3)    Painting parts or whole chiller based upon the rust conditions	1)   After shutdown. 2)   Before starting and after shutdown 3)    After shutdown.
2	Solution	1)      pH value and concentration of additives in solution 2)      Concentration of solution	1)      Sampling and analyzing the solution, and adjust it based upon the results. 2)      Measuring the concentration after dilution operation, find cause and inform the Shuangliang Service Co., if the abnormality is found.	Before starting
3	Refrigerant water	Refrigerant water density	Sampling and measuring the density of refrigerant, and regenerate it, when it is larger than 1.04.	Before starting
4	Pump	1)     Hermetically sealed pumps 2)     Vacuum pump	1)      Check the motor insulation, and measure its amperage. Inspect the bearings for metal wear, repair or replace 2)      Test purging limit capacity of vacuum pump, if below standard, find cause and deal with it. 3)      Inspect and clean vacuum pump.	Before starting Before starting After shutdown.
5	Electric parts	1)            Grounding of power supply 2)            Isolation resistance  and electric strength 3)            Check fixing of wires on terminals. 4)            Electric control and protections 5)            Electric wires and cables. 6)            Flow switch 7)            Electric elements, such as sensors, inverters.	1)       Check power supply for grounding. 2)       Check motor and control panel for isolation resistance and electric strength. 3)       Tighten screws on terminals additionally. 4)       Check the electric control and protections for their set points and actual working, check for wear of contacts and malfunction. 5）   Check and replace, if aged and corroded 6）   Check switch for its sensitivity, adjust it to normal function. 7）   Check, repair or replace based upon the actual results (for inverter, see its technical manual )	Before starting

8.1.3          Other periodical inspection

The following inspections and maintenance should be done for the items listed in Table 8-3 according to the years of operation.

Table 8-3 Items for other periodical inspection

No	Item	Content	Time
1	External systems	Clean the piping from foreign matter thoroughly, and inspect and repair the pumps, cooling towers, piping valves, electric distribution lines, fuel and gas discharging system in the machine room.	Per 2 years
2	Hermetically sealed pump	1) Replace bearing 2) Capital repair and replace.	1) Per 15,000h. 2) Per 8-10 years.
3	Vacuum pump	Capital repair and replace.	Per 5-7 years.
4	Electric adjusting valve	Inspect, repair or replace	Per 6-8 years
5	Pressure gauge	Replace.	Per 3-4 years
6	Buzzer	Replace	Per 4 years
7	PLC battery	Replace (in less than 3 min)	Per 2 years
8	Relay and AC contactor	Replace	Per 8 years
9	Electric control panel	Replace	Per 20th year
10	Cut-off valve	Replace sealing ring.	Per 2-3 years
11	Vacuum relief valve	Replace sealing ring.	Per 2-3 years

8.2 Maintenance during Shutdown Period

8.2.1 Maintenance during Short Shutdown

Short shutdown means the chiller is stopped for an interval not longer than 1-2 weeks. Maintenance in this period is listed as follows:

1)   The solution in the chiller should be diluted fully. Refrigerant water from evaporator should bypass into the absorber to weak solution and prevent crystallization, when the ambient temperature is lower than 20℃, and chiller is stopped for more than 8h. Operate the solution pump and stop refrigerant pump, connect the solution charging valve at the discharge of solution pump and refrigerant sampling valve together and open them, to prevent the refrigerant pump from freezing-up by forcing the solution into refrigerant pump, when the ambient temperature is lower than 5℃.

2)   Maintain the vacuum in chiller, operate vacuum pump, if absolute pressure in the chiller is increased.

3)   Check the chiller for air tightness, if absolute pressure in the chiller is increased too rapidly.

4)   Drain the chilled and cooling water systems (including chiller), if the local ambient temperature will be lower than 0℃ in the interval of shutdown.

5)   It is forbidden to expose the chiller to atmosphere for long time during inspection, replacing and repairing valves or pumps. The maintenance work should be planed carefully, and the chiller is evacuated immediately after the work finished.

8.2.2          Maintenance during Long Shutdown

During long time shutdown, all refrigerant should bypass into the absorber, and mixed with solution fully to prevent chiller from crystallization and heat transfer tubes from freezing up. In order to protect the refrigerant pump from freezing up during shutdown period, part of solution should be bypassed into the refrigerant pump in the procedure shown in the above first paragraph for “Maintenance during short shutdown”

During the long time shutdown the chiller should be under supervision by special appointed personnel. The chiller should be checked for air tightness, which is kept for good operation of chiller.

The solution can be left in the chiller, if it has good air tightness and solution is clear. Solution is preferred be kept in special tank to be settled, if it is turbid, and the chiller is rather severe corroded. Solution may be treated outside the chiller, and then recharged into it.

Clean the chilled and cooling water systems (including the chiller), and dry them during the long time shutdown in the following manner:

1)  From water systems drain up water, which flowing during the operation of chiller.

2)  Clean and blow the internal surface of tubes and pipes from rust and settlings (or by aid cleaning, if they cannot be removed by usual cleaning).

3)  Drain the cleaned tubes and keep them dry (the drainage piping is left opened)

8.3 Inspection of Air Tightness

Attention should be paid to the air tightness during operation and shutdown. Inspect the chiller for air tightness, if abnormality occurs. Inspection for air tightness is carried out for chiller under pressure or under vacuum in the procedure shown in the paragraph 5.1.4 “Inspection of chiller for air tightness” of chapter 5.

8.4 Inspection, Cleaning and Change of Heat Transfer Tubes

8.4.1          Inspection of Heat Transfer Tubes

1)   Inspection of scale. Open end cover of water box to check, if there is scale and sludge in the tubes. Scale is analyzed and measures should be taken, if it occurs in the tubes.

2)   Inspection of air tightness Chiller is charged with nitrogen up to 0.08MPa. Tubes are plugged from one side, and covered by a film of solution from another end. The tube is broken, if there is bubble and broken at its end, or if the plug is expanded off, when tubes are plugged from both sides. The broken tube can be observed also, if bubble comes from the tube, when water funnel is installed instead of end cover.

8.4.2          Cleaning of Heat Transfer Tubes

Tubes are cleaned once a year based upon the scale and sludge formation inside tubes.

1)   Mechanical cleaning. Mechanical cleaning is effective to remove the sludge from the tubes. Remove the end cover, blow the tubes with nitrogen or oil-less air under pressure of 0.7-0.8MPa. Then the nylon brushes (not metal wire brushes) with rubber heads and air plugs are inserted into the tubes, moved from one end of tube to another under high water pressure for 2-3 times, and then dried by high pressure nitrogen or air, or cotton balls. Cleaned tubes are protected by end covers.

2)   Chemical cleaning. Chemical cleaning is used to remove scale, which contains salt with calcium, magnesium, and other hard salts. Tubes are cleaned by chemical dosage, method and timed in accordance with the content and thickness of scale formed.

Chemical cleaning should be followed by qualified person of Shuangliang Service Co.

8.4.3         

Cooling water pump

Replacement of tubes

Leakage of chilled and cooling water through tubes will dilute solution, deteriorate vacuum, increase corrosion and influence the chiller performance. Leaky tubes should be withdrawn, changed by new ones, and then expanded. It should be prevented to make longitudinal lines in the tube plate, which will cause leakage in the connections.

8.5 Cleaning of Chiller

In addition to the LiBr solution regeneration, chiller is cleaned when it is poor maintained, has corrosion products and foreign matter in the solution, which will influence the chiller performance. Chiller is cleaned by LiBr solution, distilled water or chemical solutions. But for Shuangliang Co., chiller is cleaned solely by solution, and no distilled (or softened) water or chemical solutions can be used.  .

Cleaning of chiller by solution is similar to the operation of chiller, but with minor heat supply by steam adjusting valve. Solution of suitable temperature will wash off the dirt in the following manner:

1) Start the chiller, and operate it for a period of time, then drain solution to tank. Drained solution can be settled in solution tank, or filtered by two tanks, if the settlement takes too long time.

2) Start vacuum pump to evacuate the chiller up to high vacuum, charge it with cleaned solution, and operate it. This process is repeated to have clear solution drainage.

3) After cleaning, the chiller is tested under pressure, especially the parts disassembled.

4) Solution should be regenerated after the chiller is washed by this solution, and adjusted to the standard limits for inhibitor and content of foreign matter. Chiller is purged continuously.