Installation, Operation, andMaintenanceInstructionFor Water Cooled ChillerPrepared ByNational Cooling Towers- Mumbai

Installation, Operation, and Maintenance Instruction for Water Cooled ChillerContentContentPrefaceSafety Considerations1 Introduction1.1 Introduction of Nameplate1.2 Characters1.3 Site and Range of Use1.4 Introduction of Structure1.5 Introduction of Refrigeration System1.5.1 Refrigeration Circulating System1.5.2 Oil Circulating System1.6 Introduction of Control System2 Installation2.1 Installation Environment2.2 Site Confirmation2.3 Base Construction2.4 Carrying2.5 Installation2.6 Piping2.7 Wiring2.8 Cold Insulation3 Debugging and Trial Running3.1 Prepare for Debugging3.1.1 Prepare the Documents3.1.2 Prepare the tools3.2 Inspection before Debugging3.2.1 Inspection of Installation Status3.2.2 Inspection of Water System3.2.3 Load Inspection3.2.4 Wiring Inspection3.3 Debugging and Trial Running4 Maintenance4.1 Daily Start and Stop of the Unit4.2 Maintenance of Main Parts4.3. Contaminant Release4.4 Stop of the Unit in Winter4.5 Start of the Unit in Spring4.6 Replacement of Components4.7 Leak and Supplement of Refrigerant4.8 Anti-freezing4.9 Others5 Troubles ShootingWater Cooled Chiller Manual-1-3-4-6-6-7-7-8- 10- 10 - 11 - 12 - 14 - 14 - 15 - 15 - 17 - 18 - 19 - 21 - 23 - 24 - 24 - 24 - 24 - 24 - 24 - 25 - 25 - 26 - 26 - 32 - 32 - 32 - 32 - 33 - 33 - 33 - 33 - 34 - 36 - 38 -Page 2

Installation, Operation, and Maintenance Instruction for Water Cooled ChillerPrefaceIn order to operate the water-cooled screw chiller correctly and reach the expected runningeffect, please read this specification carefully. The following explanation is made herebybefore the operation specification:1. This specification is applicable to all types of National Chiller water-cooled chiller,including the installation, use, operation and maintenance of the unit. For the operationspecification of microcomputer control, please refer to National Chiller2. Please read this specification before installing and using the unit. If there is any question or puzzle,please contact our sales department of commercial & Industrial Chiller.3. In order to use this series of unit safely, please make sure to operate according to the requirement ofCautions for Safety.4. It is necessary to make records during the operation so as to find out the using status and the reasonof malfunction.5. Please make sure that this specification is kept directly by the operator and maintainer.6. In case of any running failure due to malfunction, please contact our sales departmentof commercial & Industrial Chiller according to the following requirements:(1) The nameplate content of the unit (part number, cooling capacity, code and exfactory date)(2) Malfunction status (explain the state before and after malfunction in details,)7. Each unit of this series is inspected and tested strictly before delivery. In case anydamage due to improper disassembly and inspection, or even inability to run normally,please do not disassemble and inspect the unit by yourself. If it is necessary todisassemble and inspect the unit, make sure to contact with our sales department ofcommercial air conditioner and disassemble and inspect the unit according to theinstruction of our professional staff.Safety ConsiderationsIt is safe and reliable to operate National Chiller Water-cooled chiller underthe designed conditions. When operating this unit, it is a must to take some safetymeasures so as to prevent from injury and damage.Before operating National Chiller water-cooled chiller, all the staff involved inon-site installation, running and maintenance should read this specificationcarefully and ensure that you understand and conform to the correct steps.Danger Avoid leak of refrigerant during debugging and use of this unit. Theacceptable density of gassy refrigerant in air (AEL) for human body is1000ppm, in which situation there is no harm for human body. However, ifthere is a great amount of leak, the gassy refrigerant will gather near thefloor, which will cause oxygen deficit. Before the gassy refrigerant isdischarged, do no approach the polluted area in case of harm to human body.Do not clean the pipe or pressurize the unit with oxygen or compressed air.Do not maintain the unit when it is energized.Do not close valves of any safety device.Do not use the test pressure exceeding specified value. Confirm theacceptable test pressure by referring to the designed pressure on thenameplate.No frame cutting or welding on the evaporator and condenser is allowedduring running of the unitWater Cooled Chiller ManualPage 3

Installation, Operation, and Maintenance Instruction for Water Cooled ChillerWarning It is better to use specialized sucking and charging device when charging therefrigerant into or sucking the refrigerant from the unit. The refrigerantdrawn from the unit should be stored in the tank that conforms to designedpressure of the unit and that is designed and manufactured according torelated standard of pressure contain.Do not discharge the refrigerant directly into the air or sewer. No directcontact between liquid refrigerant and the skin or eyes to avoid frostbite ofskin or eyes.The contact of refrigerant and naked frame will produce poisonous gas.Confirm the refrigerant type before charging it into the unit. Wrong chargingwill lead to malfunction of the unit.Inspect the safety device such as safety valve at least once every year. If theenvironment is corrosive, it is necessary to increase the inspection frequency.Once the safety valve is found to be corroded, replace it instead of repairingit.CautionDo not move the unit with fork truck.Do not tread on the pipes of the unit. Otherwise, it will lead to distortion ofthe pipe or leak of refrigerant. Use the same type of parts when repairing the unit. Inspect each valve, connector and pipe to check if they are corroded, rusted,leaked or damaged. Do not loosen the screws before completely discharging the water in the pipe. Water Cooled Chiller ManualPage 4

Installation, Operation, and Maintenance Instruction for Water Cooled Chiller1 IntroductionThis unit is designed, manufactured and inspected according to VaporCompression Cycle Water-cooled Unit for Commercial Use and Industrial Use. Ifthere is any alternation, execution would be subject to the new standard.For the main technical parameters, please refer to the nameplate of the unit.This unit should be used according to related standards of pressure container.1.1 Introduction of NameplateThe name plate is on the left side of the electric control cabinet.NCP-1005- WCNATIONAL CHILLING PLANTTon of Refrigeration(Cooling Capacity)Water Cooled Chiller1.2 Characters1. High efficiency, cramped construction, small size, low noise, large cooling capacity, longlifespan, easy operation2. Adopt widely used, high efficient, reliable and stable twin compressor. The cost ofrunning and maintaining is greatly less than other types of chiller.3. The flooded evaporator enables the distribution of the refrigerant to be more even sothat temperature pattern is optimized and the evaporating temperature is largelyincreased. Meanwhile, the heat exchange efficiency will be improved. Integrated with highperformance and reliable compressor, the cooling capacity and EER is greatly improved.4. The unit is controlled by the microcomputer control system. Stepless capacityregulation is automatic based on the variation of load. The compressor will start at lowload. Between the lowest load and the highest load, stepless capacity regulation isavailable. During the increase of the load, the output and the load maintain best matchingso that highest efficiency and energy-saving running is realized.5. Safety protection functions include anti-phase protection, overload protection, antifreezing protection, high and low pressure protection, exhaust high temperatureprotection, and water flow switch protection.1.3 Site and Range of UseNational Chiller water-cooled chiller can be used for offering cool water of air conditioningsystem and integrating with terminal Industrial unit such as Plastics Industrial andcombined Process Chiller to constitute various Industrial Chilling system. It can be usedfor Chilled Water in sites such Industrial cooling, Process chilling, hotel, hospital, mall,office building and place of entertainment.Range of use: Ambient temperature 45 6Water Cooled Chiller ManualPage 5

Installation, Operation, and Maintenance Instruction for Water Cooled ChillerItemEvaporatorCondenserMax.Min.Inlet water temperatureOutlet water temperatureDifferential temperature between inlet and outletInlet water temperatureOutlet water ifferential temperature between inlet and outlet8*C3.5*CSpecification of use range If the inlet water temperature of evaporator is lower than the value shown in theabove form, it is necessary to reselect the model. Please contact National Chiller. If the outlet water temperature of evaporator is lower than the value shown in theabove form,it is necessary to add antifreeze into the circulating water system. Please contact NationalChiller to buy low-temperature air conditioner.1.4 Introduction of StructureNational Chiller water-cooled chiller is mainly composed of semi closed twin Compressor,shell and tube condenser, flooded evaporator, oil separator, throttle mechanism, electriccontrol system and so on.1 EvaporatorDuring running of the unit, the evaporator maintains low temperature and pressure sothat the evaporated refrigerant takes away the heat of the cooling water.2 CondenserDuring running of the unit, the condenser maintains high temperature and pressure sothat the cooling water flowing throw the condenser will take away the heat of therefrigerant.3 CompressorIt will push the evaporated refrigerant in the evaporator to the condenser and maintain thedifferential pressure of the system.4 Oil separatorIt will separate the refrigeration oil from the gassy refrigerant and send it back to thecompressor so that the compressor runs safely and reliably.5 Electric control systemAdopting microcomputer control system, it is possible to adjust the output coolingcapacity automatically to meet the users actual needs. It is possible to use side, heatsource water pump and cooling tower fan. Displayed parameters include inlet and outlettemperature of cooling water, inlet and outlet temperature of cool water, evaporating andcondensing pressure ect. It is possible to check the current malfunction and the previousmalfunction record. Please refer to instruction of display for detail.Water Cooled Chiller ManualPage 6

Installation, Operation, and Maintenance Instruction for Water Cooled ChillerFig1-1 Appearance of single system unitFig1-2 Appearance of dual system unitSheet3-1 Components of National Chiller water-cooled screw chillerMark1234NameElectric control let cooling waterOutlet cooling waterInlet chilled waterOutlet chilled waterNote: the picture is for reference only. Actual matter is the standard.1.5 Introduction of Refrigeration System1.5.1 Refrigeration Circulating SystemWater-cooled screw chiller is a kind of vapor compression refrigerator. It works byenergizing the refrigerant vapor via the compressor so that the pressure and temperatureincrease. Then it is turned to liquid refrigerant of low pressure and temperature bycondensing and throttling. When it is evaporated in the evaporator, it obtains heat fromthe surrounding (cooling medium, such as cool water) to decrease the temperature of theWater Cooled Chiller ManualPage 7

Installation, Operation, and Maintenance Instruction for Water Cooled Chillercarrier so that artificial refrigeration is realized. Therefore, vapor compression refrigerationcycle includes the four necessary processes of compression, condensation, reducingexpenditure and evaporation. The principles are detailed as below:Outlet cooling waterInlet cooling waterCondenserOil separatorExpansion DeviceCompressorOutlet chilled waterInlet chilled waterEvaporatorFig.1-3 Diagram of refrigeration circulating system for National Chiller water-cooled screw chillerCompression: after the refrigerant vapor in the evaporator is inhaled by the Compressor,the electromotor increases its energy via the rotor of the compressor so that the pressureof refrigerant vapor is increased and it then it enters the condenser. At the same time, thetemperature of refrigerant vapor will increase correspondingly after compression.Condensation: the high-pressure and high-temperature refrigerant vapor fromcompressor will release heat in the condenser via the cooling water in the pipe. Meanwhileit will be condensed into liquid under the saturation pressure (the correspondingcondensation pressure for condensation temperature). In that case, the temperature ofcooling water will increase. The temperature of cooling water is directly related to thecondensation temperature (condensation pressure).Reducing expenditure: when the high-pressure and high-temperature liquid refrigerantfrom the bottom of condenser flows through the throttle device, its pressure will decreaseand it will bulge, with both pressure and temperature decreasing. Then the low-pressureand low-temperature liquid enters the evaporator.Evaporation: the low-pressure and low-temperature liquid refrigerant turns to gas byderiving energy from the cooling carrier (e.g. cool water). At the same time, thetemperature of cooling carrier decreases and the artificial refrigeration is realized. Therefrigerant vapor in the evaporator is then inhaled by the compressor for compression. Theprocesses of compression, condensation, reducing expenditure and evaporation will repeatcircularly to realize the refrigeration. The cooling capacity is in direct proportion to thesuction volume. Therefore, the guiding valve is installed in the Compressor for suctionvolume control of the compressor and evaporating capacity control of the refrigerant, sothat the cooling capacity is adjustable in certain range.1.5.2 Oil Circulating SystemWater Cooled Chiller ManualPage 8

Installation, Operation, and Maintenance Instruction for Water Cooled ChillerIn the compressor, the refrigeration oil lubricates and cools the bearing and rotor via thedifferential pressure of the system and inner oil circuit.During exhaust of the compressor, refrigeration oil will be discharged out of thecompressor together with gassy refrigerant. If the refrigeration oil can not return to thecompressor, the compressor will lack oil, which will damage the compressor. With patentdesigned oil reclaim system, National Chiller screw water-cooled chiller ensures that therefrigeration oil discharged together with the gassy refrigerant return to the compressorand that the unit runs safely and reliably.CondenserCompressorOil SeparatorEvaporatorFig. 1-4 Diagram of oil circulating system for National Chiller water-cooled screw chillerOil reclaim system includes:1. Oil reclaim via oil separator: efficient oil separator is installed between thecompressor and condenser. Most refrigeration oil discharged with gassy refrigerantwill be hold up by the oil separator and sent back to the compressor via air inlet.2. Oil reclaim via high-pressure injection: a small amount of refrigeration oil will entercondenser and finally gather in the evaporator. with the help of high-pressureliquid, the refrigeration oil gathering in the evaporator will return to thecompressor.1.6 Introduction of Control SystemWater Cooled Chiller ManualPage 9

Installation, Operation, and Maintenance Instruction for Water Cooled ChillerThe control system adopts microcomputer control, with LED of power, running andmalfunction on the panel of the control cabinet for intuitive management. In addition,emergency stop button is available on the panel of the control cabinet, which can stop theunit to ensure its safety when the emergency malfunction occurs.Warning: do not press this emergency stop button when the unit is running.Otherwise, it may damage the unit.As the compressor is the important part of the unit, the protection includes:1. Lack phase protection;2. Thermal overload protection;3. Exhaust temperature protection of the compressor;4. Inner overload protection of the compressor;5. Differential pressure protection.The above protection functions ensure the normal use of compressor.There is an operation display and a LCD on the door of electric control cabinet. The displaywill show the running information and system parameters of the unit. Different buttonshave different functions, including parameter setting, control of start and stop, statusdisplay, temperature display, malfunction display and so on. Operation, setting andinspection are available on this display.The main functions of the display or touch panel are:1. Displaying the running information of the system;2. Displaying status information of the system;3. Displaying the malfunction information of the unit;4. Setting the running parameters of the unit;5. Setting automatic timer for start and stop of the unit.Water Cooled Chiller ManualPage 10

Installation, Operation, and Maintenance Instruction for Water Cooled Chiller2 Installation2.1 Installation Environment1. The unit should not be close to fire and tinder. If it is installed together with heatingunit such as boiler, it is necessary to consider the effect of thermal radiation.2. Select those sites where indoor temperature is below 45 and is drafty. It is notpermitted to install and store the unit outside or in the open air or in the environmentwith corrosive gas.3. Select the site with less dust.4. The site should be bright for easy maintenance and inspection.5. In order to meet the needs of maintaining, inspecting and cleaning the evaporator andthe heat exchange tube of the condenser, there should be enough space for tubing, whichshould be as long as the evaporator and the condenser.6. For the sake of easy lift and overhaul, it is necessary to install traveling crane or derrickcar and ensure that the machine room is high enough.7. The surrounding of the unit and the whole machine room should be drained completely.Fig. 2-1 Dimension and diagram of running space(The diagram is for reference only. Actual matter is the standard.)Sheet2-1 Dimension and size of running space unit 06001000600NCP-135035005006001000600Water Cooled Chiller ManualPage 11

Installation, Operation, and Maintenance Instruction for Water Cooled Chiller2.2 Site ConfirmationIn order to perform the installation work safely, correctly and rapidly, the relatedinstaller should confirm the following situation beforehand:1. Installation site: confirm whether it accords with the requirement of section 2.1.2. Hole for carrying: confirm its size, height and lifting volume and remove the obstacle.3. Order of carrying: determine the way and the order of carrying according to thesituation pf installation site and equipment.4. Access for carrying: remove the obstacle on the access that precludes the carrying.2.3 Base ConstructionThe Compressor has relatively less movable parts and is stable, so the live load forbase is small. The specific dimension of base is shown in general diagram of refrigerantunit. In case of corrosion of the unit footing, it is required that the surrounding of the unitis in good drain state. The corresponding basic plane to base steel of the unit should besmooth. The specific requirements are as below:1. The maximum altitude difference (levelness) should be within 3mm.2. For easy maintenance and inspection of the refrigerant unit, the base should be higherthan 100mm3. It is necessary to install drain ditch around the refrigerant unit.4. There should be no space between the base steel and the foot plate of the refrigerantunit. Inser the adjusting shim between the base steel and the concrete base. Adjust thebase steel to be horizontal (the altitude difference should be within 0.5mm every meter. )5. The installation base of the unit must be concrete or steely structure, which can bearthe running weight of the machine. Besides, the top should be horizontal. It is better toprepare a drain ditch in the installation base,.6. Refer to the diagram of installation base. Put the steel plate and anti-vibration cushionin the correct position. Finish the installation of the unit and the foundation bolt beforesecondary grouting. The foundation bolt is generally exposed for about 100mm.Stone Concrete C300#(Secondary grouting)Footing of the unitFoundation bolt M18 (not provided by National Chiller)Installation planeIronic combConcrete C300#Solid groundAnti-vibration cushion(not provided by National)Drain ditchBACKLEFTRIGHTFRONT[Front of the unit]Fig2-2 Diagram of installation baseWater Cooled Chiller ManualPage 12

Installation, Operation, and Maintenance Instruction for Water Cooled ChillerSheet 2-2 DIMENSION of installation base Unit: 30K7407409201100121014202.4 Carrying1. Inspection of the unit: before unloading the unit, inspect the appearance and accessoryof the unit; if it is damaged, please inform the transpiration company and analyze thereason of damage and responsibility.2. Then check the quantity according to the packing list; check whether there is any lackof piece (including spare piece and spare part.). If there is any lack of part, please noticeNational Chiller distributor or sales department.3. Product model, parameter and production date are shown on the nameplate. Pleasecheck whether they conform to the contract or related technical decrements.4. Lifting:1. The lifting position is marked on the unit. After confirming the installation ofbase, shock pad and foundation bolt, place the unit on the shock pad withstrong sling (strong enough to bear the weight and impact of the unit duringlifting) via the crane.CAUTIONPlease lift the unit in strict accordance with the lifting marks on the outerpackage. Otherwise, it may cause distortion of the pipe and leak of therefrigerant.2. During lifting, in order to avoid damaging connectors of the unit, please lift theunit in strict accordance with the lifting marks.3. Do not enlace the compressor, shell and tube exchanger with slings. Do not lift theunit with bolt hole. Avoid sloping lifting.Fig.2-3 Diagram of liftingWater Cooled Chiller ManualPage 13

Installation, Operation, and Maintenance Instruction for Water Cooled Chiller2.5 Installation1. First of all, check whether the base conforms to the footing size of the unit in thegeneral diagram.The base should be smooth and level.2. Put the base steel in the prescriptive position.3. Put the refrigerant unit on the base steel.4. There should be no space between the base steel and body foot plate of the refrigerantunit.Adjusting shim should be put between the base steel and the concrete foundation. Adjustthe base steel to be level (the altitude difference should be within 0.5mm every meter);5. Lift the refrigerant unit and put the damper rubber blanket on the base steel, and thenput the unit on the damper rubber blanket.6. After installation, ensure that the horizontal slope should be within l 1000. If it isbeyond the range, adjust the unit. Put a pad (the pad is provided by the installer) betweenthe footing and the shock pad, and then check the horizontal slope until it is passed.2.6 Piping1. After leveling the unit, connect the chilled water pipe and cooling water pipe. Pipingshould have flexible parts and independently supportive capability to avoid any distortionor vibration. The pipe should be supported and correctly joined. Shock pad can be addedto the pipe supporter so as to reduce the vibration.2. There are marks near the inlet and outlet for reference when connecting the pipe. It isnecessary to connect the pipe according to the marks on the unit. Refer to Fig. 2-4 forpiping pattern.Fig. 2-4 piping diagram3. According to the general diagram, connect the pipe for cool water and cooling water(flange or clamping band connection), and set a filter in the inlet. Whether the pipe ishorizontally or vertically led from the unit to the water pump is decided by the user basedon the site condition.Manometer should be set on the inflow pipe and outflow pipe of the unit so as to measurethe differential pressure of the inlet and outlet and thus estimate whether the water flowconforms to the rated water flow. The control valve of cool water and cooling water must beinstalled on the outflow pipe of the refrigerant unit to avoid disorder of the water flow aswell as eroding the heat transfer tube near the inlet.Water Cooled Chiller ManualPage 14

Installation, Operation, and Maintenance Instruction for Water Cooled Chiller4. When the water quality is bad, there will be much deposit such as scale and sand in theshell and tube exchanger, which will decrease the water flow and affect the rate of heatexchange. Meanwhile, if the quality of chilled water and cooling water is bad, it will notonly cause scaling, affecting the rate of heat exchange and the performance of the unit,but also cause erosion of the heat exchange pipe which may lead to serious leak. Thus, thewater must be filtered and softened by the water-softening equipment before flowing intothe system. If the water quality is too bad, treat the water according to Treatment andDesign Regulation of Industrial Circulating Cooling Water. The inclosed chilled watersystem should adopt soft water. During running of the unit, it is necessary to sample thewater for analysis and the water quality should conform to the requirement of sheet 2-3.Otherwise, the water must be treated. Currently the commonly used water treating deviceis sand eliminator and water-softening equipment. If the water quality still can not reachthe requirements, add a heat exchanger between the water on side of heat source and thewater-cooled screw chiller. Actually, even if the above actions are taken, there will bedeposit such as scale and sand in the shell and tube exchanger, which will decreasethe water flow and affect the rate of heat exchange and even freeze the evaporator.Therefore, it is necessary to inspect and maintain the unit periodically.basicitemSheet 2-3 Quality of cooling wateritemstandardvaluePH value 256.5 – 8.0specific conductance 25μ S/cm800chloride ion ClMg Cl- /L200sulfate radical ion SO-2Mg SO-2 /L200acid depletion PH4.8Mg(CaCO3)/L100Full hardnessreferenceitemFerrous FeSulphur Ion S2Ammon Ion NH Monox )/L2000mg(S2-) / Lmg(NH )/LMg(SiO2)/L1.01.05000002.7Wiring1. Before electrical installation, make sure to cut off the general power supply and installthe switch cabinet in the suitable position.2. Connect the main power cord and the earth wire to the electric control cabinet throughthe service entrance. Connect the wire to the corresponding wire holder and earth wireholder. It is a must to ensure the correct connection of L1 L2 L3.3. Ensure that the voltage fluctuation of main power supply is within 10 of the valueshown on the nameplate and that the voltage unbalance is within 2 . If it exceeds thisrange, stop the unit and contact with the electric department.The formula of calculating voltage unbalance:Voltage unbalance % maximum deviation from average voltage / average voltage4. Before connecting wire of main power supply, check the phase sequence of each powercord.5. Connect the control circuit1 Connect the control wire of the AC contactor in chilled water pump, cooling waterpump and cooling tower with the flow switch and the electric control system.Water Cooled Chiller ManualPage 15

Installation, Operation, and Maintenance Instruction for Water Cooled Chiller2 The unit must be energized 8 hours before running of the unit and should bekept energizing in working seasons so that the heating tape of the compressor can heatwithout running of the compressor. In that case, the liquid refrigerant gathering in thecompressor will evaporate and avoid damaging the compressor.3 Ensure the unit is earthed reliably.6. Inlet wire of electric control cabinetA dismountable square sheet-metal piece is fitted in the inlet of electric control cabinet.When installing, please remove the sheet-metal piece and hole it according to the size ofcable terminal. Lead the cable through the hole and fix it.Fig. 2-5 Diagram of inlet wire7. Refer to the following sheet for specification of power supply and circuit breaker.Sheet 2-4 Selection of power cord and circuit breaker (R22 series)Model NCP-1Diameter of power 150185x2350240x2Diameter of earth wire(mm2)Rated capacity ofcircuit breaker 001000Sheet 2-5 Selection of power cord and circuit breaker (R134a series)Model NCP-1Diameter of power 40350150x2Diameter of earth wire(mm2)Rated capacity ofcircuit breaker 0Note: The specification of power cord refers to the specification which is chosen when thecable is led overhead and the ambient temperature is 40 . The circuit breaker is usedwhen the temperature is 40*C and it is Model The selection of power cord and circuit breaker is related to the local climate, nature ofoil, cabling and so on. This project is usually designed by the designing institute. Thelecto type calculated by the designing institute based on the maximum output is thestandard.Water Cooled Chiller ManualPage 16

Installation, Operation, and Maintenance Instruction for Water Cooled Chiller2.8 Cold InsulationThere are two situations for the cold insulation of the unit:1. The cold insulation has been finished in the factory.2.

Installation, Operation, and Maintenance . Instruction . For Water Cooled Chiller . Prepared By . National Cooling Towers- Mumbai