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Water Cooled Screw Chiller Technical Service Manual

1. Description Default Setting range Remarks User parameters Leaving chilled water set point Ts 7C 7 12 C User parameter Control range To 2 C 1 3 C User parameter Temperature control cycle of step control Smin 3 5min User parameter Mode selection Cooling Cooling pump User parameter Compressor parameters Min shut down interval of comp 15min 10 15min Commissioning parameter Min running time of comp 15min 10 15min Commissioning parameter Startup interval of comp 25min 25 30min Commissioning parameter Oil heating time 30min 0 120min Commissioning parameter Alarm parameters Low pressure protection delay 3s 0 6s Plant parameter Oil level alarm delay 60s 0 120s Plant parameter 1 compressor over load current Depending on unit model 100 500A Plant parameter 2 compressor over load current Depending on unit model 100 500 A Plant parameter Discharge temp protection point R134a 60 C 60 75 C Commissioning parameter IDischarge temp protection reset point R134a 45 C 40 55 C Commissioning parameter IHigh leaving cooling water temp protection point 45 C 40 45 C Commissioning parameter High leaving cooling water temp protection reset point 38 C 35 40 C Commissioning parameter Anti freeze protection point 4 0 C 3 5 5 C Plant parameter Anti freeze protection reset point 13 C 13 15 C Plant parameter Cooling tower
2. Unit model Oil charge Liters Unit model Oil charge Liters LSBLG340 34 LSBLG915 78 LSBLG400 36 LSBLG1000 82 LSBLG455 36 LSBLG1110 82 LSBLG540 39 LSBLG1200 92 LSBLG690 46 LSBLG1300 92 LSBLG720 46 LSBLG1385 92 LSBLG825 72 LSBLG1450 92 6 80il Filter Maintenance Each compressor has its own internal oil filter and each circuit also has an in line external filter located under the external oil separator The internal oil filter pressure drop should be checked and filter changed if necessary after the initial 2000 hours of compressor operation Oil line pressure loss is monitored by the control and reported for each compressor as the oil filter pressure drop Normally the pressure differential discharge pressure minus oil pressure is typically less than 150kPa for a system with clean internal and external filters To determine the oil pressure drop due to the oil lines and external filter only connect a gage to the oil pressure bleed port Compare this value to the discharge pressure read at the touch screen If this value exceeds 150 kPa replace the external filter 6 9Compressor Change out Sequence Compressor service requires metric tools and hardware Change compressors according to the following procedure 1 Compressor removal procedure Cut off all main and control circuit power supply of the machine Close the discharge valve suction valve and evaporator inlet line service angle valv
3. sets of personal computers USB tLAN converter Adapter ratio of pressure sensor evaporation pressure N o0 AI NI NM Bao NTC suction temperature j start controlled digital input 1 free contacts up to 230Vac N solenoid valve he W warning signs 4 4 Safety Considerations Installing starting up and servicing this equipment can be hazardous due to system pressures electrical components and equipment location roof elevated structures etc Only trained qualified installers and service mechanics should install start up and service this equipment When working on this equipment observe precautions in the literature and on tags stickers and labels attached to the equipment and any other safety precautions that apply Follow all safety codes Wear safety glasses and work gloves Use care in handling rigging and setting this equipment and in handling all electrical components Warning Electrical shock can cause personal injury and death Shut off all power to this equipment during installation and service There may be more than one disconnect switch Tag all disconnect locations to alert others not to restore power until work is completed Caution This unit uses a PLC based electronic control system Do not use jumpers or other tools to short out components or to bypass or otherwise depart from recommended procedures Any short to ground
4. Hot water flow too large or water temperature too low Regulate the water volume VII Automatic capacity adjustment device does not work Thermoregulation device trouble Change a new one Magnetic valve power off Change a new one Capillary pipe blocks Clean by professional VIII Compressor overheat Compressor bearing not good Renew the compressor Pressure of the high pressure side is too high Refer to IV Temperature of the refrigerant at the low pressure side too high Regulate the pressure of low pressure side and the width of expansion valve Motor overheat Refer to XV IX NFB tripping Layout short trouble Measure the insulation resistance Layout grounding As above Compressor motor trouble Measure the grounding insulation resistance of the compressor motor and phase to phase insulation resistance X Compressor motor overload relay action Single phase running due to NFB tripping Check it The voltage too high or too low or without balance Check the electric power distribution status Single phase running due to bad magnetic itch Repair it or change a new one Motor not good After regulating repair it or change a new one if damaged refrigeration media circuit must be cleaned Temperature inside the electric power distribution cabinet is too high Remain below 60 C find out the r
5. Measure the resistance and phase insulation resistance grounding insulation Over loading relav of compressor electromotor works NFB jumps unit runs with single phase power Voltage too high or too low unbalanced voltage Defective solenoid switch cause the unit run with single phase power Defective electromotor Temp inside distribution box is too high Over high running pressure Compressor starts frequentiv Check it Check the distribution box Repair or replace it Repair or replace it if it is burnt clean the refrigerant pipelines Keep the temp below 40 C Refer to item 4 and 5 Check all the automatic device Clean the oil filter Insufficient chilled engine oil in compressor 4 2 EXV Troubleshooting Problem Reason Solution Measured Measured superheat value is Check that the measured pressure and temperature sensors superheat value is incorrect incorrect Set the wrong type of refrigerant correctly and the correct position Check on the drive set minimum and maximum pressure pressure sensor parameter with the range of pressure sensors installed in line Check sensor electrical wiring is correct 10 liquid back to the compressor during the control Valve tvpe setting error Check and correct valve tvpe parameters Valve connection error rotation in the opposite direction and is open And manual control valve is completelv cl
6. degree of sub cooling overheat degree True and complete records of operation parameters are useful for analyzing and forecasting the trend of unit operation It s good for finding and forecasting the problem that may occur and taking measures in time For example by analyzing the record of a whole month you may find that the temperature difference of condensing temperature and leaving cooling water temperature may become bigger It means that the cooling water is dirty or water hardness is big and it is scaling constantly So it s compulsory to perform softening process or clean the tubes Note Keeping the normal operation parameters of initial unit commissioning is very useful It can be used for comparative analysis to find out the trend of problem gt Scheduled maintenance General Take notice of the noise at any time by standing 1m from the unit Watch the vibration amplitude at all times to see whether it s within permitted Check the voltage of power supply whether it s within 10 of rated voltage at any time Visual inspection Keep the unit clean if there s rust do scaling with iron brush and cover it with antirust paint Pay attention to the oil traces sign of a refrigerant leak and water traces on pipeline Check the threaded connection joints carefully fasten any loose screw in time Any time seeing the insulating material flakes off stick them with adhesive Compressor For insulation resistance check it yearly and it shou
7. 50 60Hz M L1 L2 L3 Time Imin2 205 JTX A l Relav A0230V SA L N S1 S2 M1 M2 Thermal overload relay Each compressor is eguipped with one thermal overload relay to protect the compressor against overcurrent Bypass the current transducers or make any changes to the factory default set points is forbidden The configuration of the module defines the Must Trip Amps MTA at which the thermal overload relay will turn the compressor off High low pressure switch All compressors have factory installed high low pressure switches See Table 6 10 Table High low pressure switch settings High pressure switch setting Low pressure switch setting UNIT psig MPa psig MPa LSBLG 145 1 29 0 2 Table 6 10 If the high pressure switch continuously opens for 3s during operation the compressor will be shut down A manual reset of the control is required to restart the compressor If the low pressure switch continuously opens for 1s during operation the compressor will be shut down It will reset automatically when malfunction gets solved and cleared on the malfunction record page of touch screen Sometimes if the malfunction cannot be solved by reset consider replace the pressure switches Oil separator heaters Each oil separator circuit has a heater located under the bottom of oil separator The heater is energized with control circuit power Oil heaters are energized when unit is shut off and deenergized when
8. Typical refrigerant cycle system for single head unit eese eene 8 4 Typical refrigerant cycle system for double head unit nennen 8 5 Midea s recommendations on heat exchange fluids 8 6 Start Up Checklist for Midea Screw Chiller esee nennen entente nnne nnne Controls Start Up Operation Service and Troubleshooting 1 SAFETY CONSIDERATIONS 1 1 Installation safety considerations Access to the unit must be reserved to authorized personnel qualified and trained in monitoring and maintenance The access limitation device must be installed by the customer After the unit has been received when it is ready to be installed or reinstalled and before it is started up it must be inspected for damage Check that the refrigerant circuit s is are intact especially that no components or pipes have shifted e g follow ing a shock If in doubt carry out a leak tightness check and verify with the manufacturer that the circuit integrity has not been impaired If damage is detected upon receipt immediately file a claim with the shipping company Strongly recommend employing a specialized company to unload the machine The units can be lifted with slings using only the designated lifting points marked on the unit Use slings with the correct capacity and always follow the lifting instructions on the certified drawings supplied with the unit Safety is only guaranteed if these instructions are carefully follo
9. are subject to change with product improvement please take chiller nameplate as final 45 APPENDIX D cont I O summary sheet Signal inputs Code Description Type Function Remarks DI 00 Remote start Inching NO For remote control Provided by user DI 01 Remote stop Inching NO Provided by user For remote control DI 02 Chilled water flow protection NC Lacking of water protection Open circuit 5s activate DI03 Cooling water flow protection NC Lacking of water protection Open circuit 5s activate DI 04 Anti freeze protection NC Protect the evaporator real time detection DI 10 14 High pressure protection NC Discharge pressure protection Delayed malfunction detection DI 11 1 Low pressure protection NC Suction pressure protection Delayed malfunction detection Protection of phase loss phase DI 12 1 Compressor protection NC unbalance phase reversal over high Open circuit 1s activate discharge temp DI 13 1 Oil level protection NC In case of lacking of oil Open circuit 3s activate Determine by DI 14 14 Overload protection electric control Overcurrent protection Delayed malfunction detection DI 15 1 Phase protection NC Power protection Delayed malfunction detection DI 20 2 High pressure protection NC Discharge pressure protection Delayed malfunction detection DI21 2 Low pressure protection NC Suction pressure protection Delayed malfunction detectio
10. reduce the vacuum to at least 130Pa 21mmHg A mercury manometer or an electronic or other type of micron gauge must be connected at the farthest point from the vacuum pump For readings below 130Pa an electronic or other micron gauge must be used The triple evacuation method is recommended and is particularly helpful if the vacuum pump is unable to obtain the desired 130Pa of vacuum The system is first evacuated to approximately 660Pa 5mmHg Dry nitrogen is then added to the system to bring the pressure up to Zero Then the system is once again evacuated to approximately 230Pa 2mmHg This is repeated three times The first pulldown will remove about 90 of the noncondensables the second about 90 of that remaining from the first pulldown and after the third only 0 290 noncondensables will remain Checks on refrigerant charge To verify if the unit is operating with the correct refrigerant charge perform the following checks 1 Run the unit at maximum operating load 2 Check the leaving chilled water temperature to be between 6 8 C 3 Check the entering cooling water temperature to be between 25 and 32 C 4 Under the above mentioned conditions verify the following items a The discharge superheating to be between 8 and 15 C b The sub cooling to be between 4 and 6 C c The difference between leaving water temperature and evaporating temperature to be in 0 5 4 C range d The difference between condensing temperature and co
11. the oil back into the compressor for compressor seal and lubrication of all moving parts During the compression the oil joints the discharge gas before being conveyed again into the oil separator and re start the cycle The oil flow is granted by the pressure difference created between the condenser and the evaporator This difference depends on the cooling water and evaporator water temperatures During the start up it is vital to establish rapidly the appropriate temperature difference by checking the right cooling water temperature The head of cooling water pump at zero flow rate should not exceed the maximum working pressure of condenser and plant water side 6 60il recovery system Each compressor includes a system to recover the oil accumulated inside the evaporator during the normal operation This system consists of a jet pump able to collect continuously all the oil from the evaporator preventing from the accumulation due to the low speed refrigerant gas The high pressure discharge gas feeds the jet pump that creates a depression which allows the suction of the oil refrigerant mixture from the evaporator into the compressor to re establish the oil level inside the lubrication system On the oil recovery piping a sight glass allows to check the oil gas mixture flow to the compressor If flow is insufficient or if the unit continuously stops for Low Oil Level alarm verify the correct operation of the corresponding circuit 6 70il Chargi
12. the valve is rotating in the opposite direction check the electrical wiring Valves damaged or connected incorrectiv the stator The stator and the valve and disconnect the cable connection with ordinarv measuring coil resistance tester Two coil resistance should be around 36 Euro Otherwise replace the stator Finallv check the cable connection to connect the drive Valve can not open Started using the manual control valve fullv open If the superheat value is still high check the electrical wiring and or replace the valve Control process equipment due to low and off only comes with the compressor equipment LOP protection disabled The LOP integration time is set to greater than 0 seconds LOP protection invalid Ensure that the needs of the LOP protection threshold in the saturation temperature of evaporation evaporation temperature and the rated voltage corresponding to the temperature scale switch between and reduce the LOP integration time Solenoid valve block Check the solenoid valve opens correctly check the electrical wiring and relay operation Lack of refrigerant Check expansion valve upstream of the observation hole no bubbles To ensure proper cooling temperature greater than 5 C or refrigerant filling Valve is too small Replaced with a larger valve Valves damaged or connected incorrectly the stator The stator and the valve and disconnect the cable connect
13. to work at higher levels Use mechanical lifting equipment crane hoist winch etc to lift or move heavy components For lighter components use lifting equipment when there is a risk of slipping or losing your balance Use only original replacement parts for any repair or component replacement Consult the list of replacement parts that corresponds to the specification of the original equipment Do not drain water circuits containing industrial brines without informing the technical service department at the installation site or a competent body first Close the entering and leaving water shutoff valves and purge the unit water circuit before working on the components installed on the circuit screen filter pump water flow switch etc Do not loosen the water box bolts until the water boxes have been completely drained Periodically inspect all valves fittings and pipes of the refrigerant and hydronic circuits to ensure that they do not show any corrosion or any signs of leaks It is recommended to wear ear defenders when working near the unit and the unit is in operation 2 MAJOR SYSTEM COMPONENTS 2 1Programmable Logic Controller PLC Communication with the PLC the unit used to display operating status set the unit operating mode operating parameters and control unit 2 2Electronic Expansion Valve EXV drive module Connected through a module above the temperature sensor and pressure sensor to calculate the compressor is running i
14. unit circulate water through evaporator continuously to prevent freezing and possible damage to the evaporator Do not overcharge and never charge liquid into the low pressure side of system If the system is under a vacuum stand the refrigerant drum with the connection up and open the drum and break the vacuum with refrigerant gas to a saturated pressure above freezing 30 With a svstem gas pressure higher than the equivalent of a freezing temperature invert the charging cvlinder and elevate the drum above the condenser With the drum in this position valves open water pumps operating liquid refrigerant will flow into the condenser Approximatelv 7590 of the total requirement estimated for the unit can be charged in this manner After 75 of the required charge has entered the condenser reconnect the refrigerant drum and charging line to the service valve on the bottom of the evaporator Again purge the connecting line stand the drum with the connection up and place the service valve in the open position 6 5Compressor Oil System Each compressor circuit has its own oil system which includes an oil filter oil solenoid valve Venturi tube oil separator heater and an oil shut off valve A typical oil system is shown in Fig 34 See Table 33 for oil charge Quantities dle Fig 34 Each screw compressor is connected to a tank oil separator separating and collecting the oil from discharge gas The discharge gas pressure pushes
15. unit starts Make sure the refrigerating oil has been heated for enough time normally It s 2 8 hours The default heating time is 4 hours if the heating time is less than 4 hours the unit won t start So please energize in advance make sure there s 4 hours heating time at least The heating time of refrigerant oil is different in accordance with the ambient temperature heating time is as longer as ambient temperature lower 35 gt Evaporator protection Low Water Temperature PLC is programmed to shut the chiller down if the leaving water temperature drops below 4 C When water temperature rises up to 13 C the safety resets and the chiller restarts Besides the chillers are equipped with antifreeze switch which located on the outlet of chilled water If leaving water temperature continuously keeps lower than 3 C for 3s during operation the chiller will be shut down When water temperature rises up to 10 C the chiller resets but it needs manually reset on the touch screen IMPORTANT If unit is installed in an area where ambient temperature may fall below 32 F 0 C a suitable corrosion inhibited antifreeze solution or auxiliary electric heater must be used in the chilled water circuit Relief Devices Pressure relief valves Relief valves are installed on evaporator condenser and oil separator These valves are designed to relieve if an abnormal pressure condition arises Relief valves on evaporator relieve at 220 psi 15
16. 17 kPa Relief valves on condenser relieve at 220 psi 1517 kPa Relief valves on oil separators relieve at 320 psi 2206 kPa These valves should not be capped If a valve relieves it should be replaced If not replaced it may relieve at a lower pressure compared to the set point or leak due to trapped dirt from the system which may prevent resealing Control Modules Main base board mbb screwcompressor Board scb expansion valve board exv Energy management module emm ComfortlinkTMcompressor protection Board ccp and the navigator Red led Green led Yellow led Replacing Defective PLC Controller For Midea screw chiller it adopts special refrigeration PLC controller The program and data is written into the memory by Midea in the replacement module When ordering any replacement module specify the model of unit and information of user Name Country Installation time of unit Return the faulted module to Midea Caution Electrical shock can cause personal injury Disconnect all electrical power before servicing 1 Check that all power to unit is off Carefully disconnect all wires from the defective module by unplugging its connectors Remove the defective module by removing its mounting screws with a Phillips screwdriver and removing the module from the electric control box Save the screws in an appropriate place for later use 2 Package the defective module in the carton of the new module for return to Midea
17. 3 Install the new module in the unit s control box using a Phillips screwdriver and the screws saved before 4 Reinstall all module connectors and communication wire Carefully check all wiring connections before restoring power Make sure the connectors are installed at the right place 5 Restore control power Verify all configuration information settings set points and schedules 36 7 Maintenance 7 1Operation checks IMPORTANT Before beginning Pre Start Up or Start Up complete the Start Up Checklist for Liquid Chillers on pages APPENDIX cont This Checklist assures proper start up of the chiller and provides a record of unit condition application requirements system information and operation at initial start up Keep it properly with the job file for future reference gt System inspection before startup a Valves on all circuits Confirm whether the valves on suction discharge pipe oil return pipe and feed pipe are open or not and whether the pipes are clear Make sure the ball valves of relief valves are open All water valves maybe butterfly valves are correctly open b Check oil heating time Judge whether the refrigerating oil has been heated for enough time normally It s 2 8 hours The default heating time is 4 hours if the heating time is less than 4 hours the unit won t start So please energize in advance make sure there s 4 hours heating time at least The heating time of refrigerant oil is different in ac
18. 509 regain 10090 load after 10 mins later Operation current limit control During unit running it will unload immediately when the current reach 9596 of set point and will not execute capacity increase action Stop unloading until compressor unloads to 50 After unloading operation for 10mins and the current value lt 70 of set point and the unit meets loading condition the unit will reload step by step 5 6Protection Items And Troubleshooting Midea screw chiller has many protection measures and devices There re many features to aid in troubleshooting By using the alarm information DI O AI O and operating conditions of the chiller during chiller operation it s convenient to find the possible problem Verify that the chiller is properly configured including options and or accessories Self diagnosis of malfunction and protection When malfunction and protection occurs compressor and other devices are all shut down Water pump will keep on running if it s not the problem of water system One compressor failure does not affect the other one Some malfunction and protection has configurable time delay set point to avoid protection switch fluctuation Low pressure alarm 3s Oil level alarm 60s Water flow switch trip 5s Reset of water flow fault on screen is invalid interface restart is required Otherwise press reset button on screen to restart for other fault and protection trip 25 After fault and prote
19. 7 55 C Commissioning parameter High leaving cooling water temp protection point 45 C 40450 Commissioning parameter High leaving cooling water temp protection reset 38 C 35400 Commissioning parameter pep cooling water temp protection point 14 C 14 20 C Commissioning parameter Low entering cooling water temp protection reset 38 C 18 22 C Commissioning parameter pe m protection point 4 0 C 3 0 5 C Plant parameter Anti freeze protection reset point 13 C 10 15 C Plant parameter Cooling tower parameters Cooling tower fan ON temp 27 C 18 27 C Commissioning parameter Cooling tower fan OFF temp 25 C 18 25 C Commissioning parameter Oil supply parameter Time delay of oil return SV ON 2s l 5s MD Time delay of oil return SV OFF 300s 200 5000s da c d Display Depending on unit model Commissioning parameter 1 ff Full load current of compressor 50 500A Depending on unit model Commissioning parameter 2 ff Full load current of compressor 50 500A 49 APPENDIX F cont 8 3Tvpical refrigerant cycle system for single head unit P p Oil Separato Code Name RG P Pressure gauge 1 1 a Temperature sen
20. 720MCF1 ELECTRICAL CONTROL POWER SUPPLY OF FU KA KT FR KR TI AG KC n 312 AKAMAXKARARAZKARKJANRJJO MHNENEUNUS OOOO OOOO nd zean Ot we u bo Caig ar tu od er WW LSBLG825MCF1 LSBLG1450MCF1 POWER SUPPLY ELECTRICAL CONTROL ellet fef zl DOTA UG II H uet 1 ION OOOO OOOO ON LAF A HH i Fig 15 Field wiring for dual heads unit 40 APPENDIX A 8 2Trouble shooting Svmptom Cause Troubleshooting I Compressor does not work No power power cut off Check and deliver power Switch action current overload Find out the reason for current overload If the switch volume is too small change the switch in time If the pressure is too low try to improve it Trouble of startup switch Examine and change Fuse of the control circuit power source burnt out Change Chain control part does not run Check whether the water pump of the chain control runs if not make it run High and low pressure switch action Check the set pressure and regulate II Stop soon after it starts up High and low pressure switch action Ambient temperature is too high exclude the incondensable gas if the expansion valve blocks clean it if it is damaged change it clean awav the dust on the fin heat exchanger III Discharge pressure too low refrigerating status Refrigerant not enough Add Re
21. FF or ON if water flow switch opens for 5s continuously the unit will not start or stop immediately gt Condenser pump control The condenser pump can be controlled in the way like the cooler pump It is turned on whenever the machine is in an ON mode and turned off 60 seconds after all compressors stop When configured for a condenser flow switch interlock an alarm of cooling water flow loss is generated if the input does not close after unit starts for 2 min and fault will be displayed on the operation interface Flow Sensor Water flow protection All water pipe kits and water flow switches are provided Water flow switch must be installed on the outlet of both the Condenser and Evaporator and the length A of water flow switch should be 5 times the length of the pipe diameter Adjust the target of water flow switch according to the water pipe specification Refer to the manufacturing manual Water flow switch is connected to the terminals in control cabinet refer to the electrical wiring diagram for details Water flow switch gt j 4 E gt gt FLOW jg s ma gt Distance A must be 5 times the length of water pipe diameter FLOW When power is supplied to the device PLC control begins to detect water flow after water pumps running for 3 minutes If water flow switch keeps open for 5s the chiller will stop It needs manually reset Perfor
22. Fe2 and Fe3 ions with non negligible levels of dissolved oxygen must be present Dissolved iron lt 5mg l with dissolved oxygen lt 5 mg l If possible keep below lt 0 3ppm 7 Dissolved silicon silicon is an acid element of water and can also lead to corrosion risks Content lt 30ppm 8 Water hardness Total hardness lt 50ppm can be recommended This will facilitate scale deposit that can limit corrosion of copper A total alkali metric titer TAC below 100 is desirable 9 Dissolved oxygen Any sudden change in water oxygenation conditions must be avoided It is as detrimental to deoxygenate the water by mixing it with inert gas as it is to over oxygenate it by mixing it with pure oxygen The disturbance of the oxygenation conditions encourages destabilization of copper hydroxides and enlargement of particles 10 Specific resistance electric conductivity the higher the specific resistance the slower the corrosion tendency Conductivity 20uV cm 25 C are desirable A neutral environment favors max specific resistance values For electric conductivity values in the order of 200 6000S cm can be recommended 11 PH Ideal case pH neutral at 20 25 C 7 lt pH lt 8 5 CAUTION Water must be within design flow limits clean and treated to ensure proper chiller performance and reduce the potential of tube damage due to corrosion scaling erosion and algae Carrier assumes no responsibility for chiller damage resulting from untreated
23. MPa Higher pressure can be customized mm DN125 DN125 DN125 DN150 DN150 DN150 DN150 Pipe connections in 5 5 5 6 6 6 6 type Flooded type Pass No 3 3 3 3 3 3 2 Evaporator Water flow rate m h 58 69 78 93 119 124 142 Water pressure drop kPa 50 55 58 60 62 65 65 43 Water side working pressure MPa 1MPa Higher pressure can be customized mm DN125 DN125 DN125 DN150 DN150 DN150 DNI50 Pipe connections in 5 5 5 6 6 6 6 Length mm 3500 3500 3500 3600 3600 3600 4500 Dimension Width mm 1400 1400 1400 1500 1500 1500 1600 Height mm 1750 1750 1750 2000 2000 2000 1900 Shipping weight kg 3000 3200 3300 3800 4000 4100 5500 Operating weight kg 3300 3550 3650 4200 4450 4550 6000 Specifications of LSBLG screw chiller Model LSBLG LSBLG LSBLG LSBLG LSBLG LSBLG LSBLG 915 1000 1110 1200 1300 1385 1450 Items RT 260 0 2844 315 7 341 3 369 7 393 9 412 4 Nominal Cooling Capacity kW 914 1000 1110 1200 1300 1385 1450 kCal h 786 040 860 000 954 600 1 032 000 1 118 000 1 191 100 1 247 000 Power input kW 64 0 162 3 177 3 200 9 210 0 232 1 243 4 Electrical data Rated current A 107 6 272 8 298 1 337 7 353 0 390 2 409 2 Power supply 380 415V 3P 50Hz Capacity control Automatic Capacity steps 25 50 75 100 or stepless as option Type Semi hermetic twi
24. Water Cooled Screw Chiller Technical Service Manual Climate solution for green environment contents 1 Safety Considerations od AA AA a td 1 1 Installation safety considerations ooonoconoconocononononanonononnnnnnnnnn nn non nan rra nena eee narrar 1 2 Maintenance safety considerations anna nr enne ennemi nennen nnne nre nene tna 3 Repair safety consideratiODs ooi i re ra e e eren axe de E eae ee de a Eee Eee a g 2 Major System Components ssssssesssssseeseeeen enne entren inns et rns sn rese testes nenne 2 1 Programmable Logic Controller PLC eese nor narra rr nennen 2 2 Electronic Expansion Valve EXV drive module eese 2 3 Compressor Protection MOU cs sities rei esi eene eie eerta eine ho Feds eusnsdieesinesanesanedaes 2 4 Emergency Stop 3 Operation Data 3 1 EXV Operation 3 2Alarms Alerts SWILCI A A el i Md Y FO Lm ed 4 Protection items and Troubleshooting eese eene 4 1 Protection items and Troubleshooting items nn entente nnne 4 2EXV Troubleshooting Procedure terree erret e Rr cond Ret e eene dune eee He Ene an 4 3 EXV Operation And WATS vive iesu una entre det eder tere e aeter agere nate aethera rae Qa ede ng 4 4 Safety ConsideratiOn Si eet e n me Here oe dat Y eue eere ehe 5 Control 5 1 Capacity Control 5 2 Head Pressure Control ieiet NG ddu eee eme toe
25. agger in the defrosting absence of the first two issues in the case will involve the refrigerated cabinet superheat setpoint and at least 2 C LowSH threshold increase The valve is too large The replacement for the smaller valves Liquid only at Parameter start control valve Reference to the evaporator cooling capacity and rated start controller closed when opening degree set too high capacity of the valve than check this parameter value necessary to reduce this value 11 returning to the compressor Superheat value is about swing around the set value and larger Condensing pressure instabilitv Check the controller condenser settings set the parameter to the more moderate values such as increasing the proportion with or increasing the integration time Note the need for stability including 0 5 bar changes If this does than 4 C not work or can not change the settings In the oscillation system used in electronic expansion valve control parameters Even if the valve is set to Check the cause of instability such as the refrigerant charge manual control mean value in 1s less and try to solve the corresponding position with If not feasible in the oscillation system used in the the work the value remains electronic expansion valve control parameters stable superheat Will set the manual control First try to reduce the scale factor 30 to 50 and then valve in the positio
26. alized technicians Take apart the connecting pipe of safety valve and check it to see whether there is corrosion rust scaling leakage phenomenon internal if necessary replace the safety valve And also check other operating valves to see whether it s smooth when opening or closing them 38 A High low pressure switch Check their performance whether they are in good condition according to performance of protection device monthly and change the broken one in time Or the chiller may get damaged when over high pressure or too low pressure happens 7 3Chilled water cycling Seek the possible leakage on the unit and the pipe joint with leak detector Expel the water from condenser and evaporator to see whether there s leakage on water inlet and outlet Leak can be found with electronic detector torch detector or soap water The work looking for refrigerant leakage should be carried out at least once month 7 4Electrical control system For insulation resistance check it monthly and it should be over IMQ when measuring with ohmmeter of 500VDC Check the running current and compare with the rated value refer to Table 9 Check the conductibility of wire and verify whether it s intact and well connected Fasten the loose bolts Check other components such as electromagnetic contactor rotary switch auxiliary relay time relay and thermostat whether they are all normal monthly 39 S APPENDIX A 8 1Field wiring LSBLG340MCF1 LSBLG
27. atment Before every start up clean and flush the cooling water circuit Make sure tower blow down or bleed off is operating It should be recognized that atmospheric air contains many contaminants that increase the need for proper water treatment The use of untreated water can result in corrosion erosion sliming scaling or algae formation Midea assumes no responsibility for the results of untreated or improperly treated water Q 29 See appendix for water qualitv requirements 6 4Refrigerant Circuit gt Leak testing Units are factory charged with refrigerant R 134a Refer to the Physical Data tables supplied in the IOM manual book Leak test must be done under sufficient pressure This can be done by charging enough refrigerant into the system to build the pressure up to approximately 70 kPa and adding sufficient dry nitrogen to bring the pressure up to a maximum of 850 kPa Leak test with an electronic leak detector Water flow through the vessels must be maintained anytime refrigerant is added or removed from the system If any leaks are found in welded or brazed joints or it is necessary to replace a gasket relieve the test pressure in the system before proceeding Brazing is required for copper joints After leaks are repaired system must be evacuated and dehydrated gt Evacuation After 1t has been determined that there are no refrigerant leaks the system must be evacuated using a vacuum pump with a capacity that will
28. aving chilled water temperature gets lower than 4 C perform low water temperature protection and stop according to abnormal protective shutdown program Cooling water pump chilled water pump cooling tower fan 26 keeps on running When leaving chilled water temperature gets higher than 137C unit resets When both temperature and time condition gets satisfied the chiller can restart Mechanical antifreeze switch The switch trips when leaving chilled water temperature lt 39C and chiller stops according to abnormal protective shutdown program Reset at 10 C and fault on screen must be cleared manually when both temperature and time condition gets satisfied the chiller can restart Compressor protection module Alarm when compressor protection module trips Perform abnormal protective shutdown program immediately Fault on screen must be confirmed and cleared manually when both temperature and time condition gets satisfied the chiller can restart Compressor overload protection Thermal overload relay trips when heat storage reaches trip point Faulted compressor will stop immediately to abnormal protective shutdown program and other normal system will keep on running After the switch reset fault on screen must be confirmed and cleared manually when both temperature and time condition gets satisfied the chiller can restart Oil level protection During unit running if oil level keeps on lower than set point for 60s the unit will stop i
29. ce Compressor Motor Thermistors A thermistor is factory installed in each compressor Connections for the thermistors are located in the compressor wiring box 2 terminals are reserved for the thermistor SI and S2 Motor temperature is measured by leads connected to S1 and S2 terminal The thermistors are not serviceable in the field If the compressor motor thermistor fails compressor replacement is required 6 10Safety Devices Compressor protection module INT69 HBY JTX A The units are equipped with compressor protection modules built in the wiring cabinet of compressor INT69 HBY and JTX A module is designed to detect the motor winding temperature phase sequence and phase loss The detecting signal of JTX A is voltage type When motor winding temperature reaches set point the module will cut off control circuit immediately The module with phase sequence control can prevent motor reversal due to the 34 adverse consequences When any one phase loses the module will cut off main power after a short delay to protect the motor from burning When phase unbalance happens it cuts the power immediately In order to avoid interference and discriminate between false voltage drop and malfunction as phase loss or phase unbalance during motor operating JTX A will cut off main power after 3 5s delay JTX A amp PT Cin RE ft I SERA AC 380V AC 220V 13 12 LI N L J Ea aah JE 5 10 SP YIN AE ZM zM JTX A Motor Protective Relay EP TI
30. cooler pump interlock 23 All chiller cooler pump control is utilized unless the chilled water pump runs continuously or the chilled water svstem contains a suitable antifreeze solution It is recommended that the cooler pump should be interlocked with the unit unless there re other antifreeze solutions When the cooler pump control is ON the cooler pump relay will be energized when the chiller enters an ON mode The cooler pump relay will remain energized for 10 min after all compressors stop due to off command in order to prevent freeze up In the event a freeze protection alarm is generated the cooler pump relay will be energized whether cooler pump control is configured ON or OFF The cooler pump relay is also energized anytime a compressor is started as well as when certain alarms are generated The cooler pump relay should be used as an override to the external pump control if cooler pump control is not utilized IMPORTANT If the cooler pump control relay output is not wired to control or override the operation of the chilled water pump An OFF DELAY of 10 minutes must be provided after the chiller is disabled to maintain cooler water flow during the pump down period If the chilled water flow switch interlock does not close within 5 minutes after the unit is enabled and in an ON mode when cooler pump control is turned OFF or ON water flow loss alarm will be generated No matter water pump is O
31. cordance with the ambient temperature heating time is as longer as ambient temperature lower c Check the pressure gauges Check the main unit whether its pressure is normal Normally when indoor temperature is 25 C 28 C high low pressure is 0 7 1MPa Check the quantity of water Check whether there is enough water or not in chilled water circle system and cooling water circle system and keep an eye on water supply valve whether it is open d Check accessory components Gaskets and packing normally relax by the time the machine arrives at the jobsite due to vibration in the process of transportation Tighten all gasketed joints to ensure a leak tight chiller Check electrical distribution cabinet switches and components if there is abnormal phenomenon e Check the power Check the power supplies its voltage phase frequency whether they are normal or not f Inspect the water piping Check the piping to the evaporator and condenser Use proper fluids and consult Midea s recommendations on heat exchange fluids AnnualStartup This is a good time to check all the motor winding resistance to ground Semi annual checking and recording of this resistance will provide a record of any deterioration of the winding insulation All new units have well over 100 MQ resistances between any motor terminal and ground 1 The control circuit must be energized at all times except during service If the control circuit has been off and oil i
32. creen as shown The display will show the contents and if you are debugging drivers will begin to display configuration oriented program 14 A Warn If you did not complete the configuration process the drive will not start Front panel display and keypad keypad has 6 buttons drive all the configuration and programming available through a separate press a button or press a few buttons to complete Display and keypad Graphical display with two kinds of system variables the drive control of the state protection function is activated and the alarm and relay output status Aper kura valvola press Display first kinds of variables Display second kinds of variables Relay output status Alarm Start of the protection AJAJ AJIN Control state Display Control state Type of protection running ON Run LowSH Low superheat protection OFF Standby LOP Low evaporation temperature protection POS Locate MOP High evaporation temperature protection SAB MU Wait HiTcond High condensing temperature protection CLO SE Close Keypad Button Function Prg Open the display screen enter the password to enter the programming mode 2 BA In the alarm state the display alerts the gueue ET When the producer level under the rolling parameters the display shows the interface Esc To exit the programming maintenance prod
33. ction trip occurs confirmation on screen is required Unit stops according to abnormal shutdown program Fault and protection detection gt Phase reversal phase loss phase protection Power supply A B C should exist simultaneously and differ from each other by 1207 phase angle If not Phase reversal or phase loss fault will occur and be displayed on screen Before unit start when Phase reversal or phase loss fault occurs the chiller won t start when Phase reversal or phase loss fault occurs during chiller operating the chiller will stop according to protective stop program Both compressors are shut down and water pumps and cooling tower fan stops in accordance with normal shutdown procedure When fault record gets cleared and both temperature and time condition gets satisfied the chiller can restart gt Water flow failure both chilled water and cooling water PLC controller begins to detect chilled cooling water flow switch after water pumps get energized 180s The switch will disconnect if water flow less than set point and water flow loss signal will generate if it lasts for 5s During chiller operation including dual heads unit any flow switch disconnects for 5s continuously Unit stops according to protective stop program If chilled water flow fails chilled water pump stops after 30s delay cooling water pump and cooling tower stops after 60s delay If cooling water flow fails cooling water pump and cooling tower stops after 60s dela
34. d Check that the valve can be closed to complete a full cycle for calibration If necessary repair or manufacturer in programming mode set the superheat setting or as the use of recommended values CAREL reserves and the protection threshold LOP MOP etc See Chapter 7 protection General wiring diagram gi Power Supply E V connection LM em EVD evolution WAM Hy Network TALE Terminal Explanation 2175 G GO Power supply VABT Emergency Power Supply E Functional ground 1 2 3 4 Stepper motor power supply COMI NOI Alarm Relay GND Signal Ground VREF Sensor power supply S1 Sensor 1 pressure or an external signal 4 to 20mA S2 Sensor 2 temperature or 0 to 10V external signal S3 Sensor 3 pressure S4 Sensor 4 temperature DH Digital input 1 DI2 Digital input 2 p Connection tLAN pLAN RS485 Modbus terminal Connection tLAN pLAN RS485 Modbus terminal Connection pLAN RS485 Modbus terminal aa Service port after removal of the cover need to be connected LED EXy aer PEE Y em p 1 y y Sporan DANFOSS 1 SEI SEH SER I m E E x 230 Vac 24Vac 2AT 30VA vg without battery Modbus Lm RS485 Eo sh EVDO000EO tLAN version EVDO000E1 pLAN version EVDO000E2 RS485 version 18 Note 1 Green vellow Brown white
35. d leaks must be repaired immediately The authorized technician must have the responsibility to repair the fault immediately Each time repairs have been carried out to the unit the operation of the safety devices must be re checked If a leak occurs or if the refrigerant becomes contaminated remove the complete charge using a recovery unit and store the refrigerant in mobile containers Repair the leak detected and recharge the circuit with the total R 134a charge as indicated on the unit name plate polvolester oil Do not use oxvgen to purge lines or to pressurize a machine for anv purpose Oxvgen gas reacts violentiv with oil grease and other common substances Never exceed the specified maximum operating pressures Verifv the allowable maximum high and low side test pressures bv checking the instructionsin this manual and the pressures given on the unit name plate Do not unweld or flamecut the refrigerant lines or anv refrigerant circuit component until all refrigerant liquid and vapour has been removed from chiller Traces of vapour should be displaced with drv air nitrogen Refrigerant in contact with an open flame produces toxic gases The necessarv protection equipment must be available and appropriate fire extinguishers for the svstem and the refrigerant tvpe used must be within easv reach Do not siphon refrigerant Avoid spilling liquid refrigerant on skin or splashing it into the eyes Use safety goggles Wash any spills from the sk
36. dicating element must be in contact with liquid refrigerant to give true reading Liquid Line Service Valve This valve is located ahead of the filter drier and provides a 1 4 in Schrader connection 30GXN R only for field charging In combination with compressor discharge service valve each circuit can be pumped down into the high side for servicing Thermistors For PTC thermistors resistances vary with various temperatures Location Motor thermistor locates in the motor winding and is connected to the compressor protection module which will cut off the main power when motor winding temperature exceeds 110 C Water temperature thermistors are installed in wells on chilled water inlet outlet and cooling water inlet outlet Refer to the electric control wiring diagram for detail connection information Thermistor replacement To Replace Thermistors RTI RT2 RT3 RT4 RTS or RT6 Entering Leaving chilled Water Entering Leaving cooling Water Discharge Gas Temperature Disconnect appropriate connector from the PLC controller New thermistors should be spliced to existing wiring close to the connector unless new connectors are required Remove thermistor cable from harness Remove and discard original thermistor from well Insert new thermistor in well body to its full depth Add a small amount of thermal conductive grease to thermistor probe and well Tighten the screw to prevent thermistors from slipping out of the well ToServi
37. dures must be carried out with the unit shut down NOTE The unit must never be left shut down with the liquid line valve closed as liquid refrigerant can be trapped between this valve and the expansion device This valve is situated on the liquid line before the filter drier box During any handling maintenance and service operations the engineers working on the unit must be equipped with safety gloves glasses shoes and protective clothing Never work on a unit that is still energized Never work on any of the electrical components until the general power supply to the unit has been cut using the disconnect switch es in the control box es If any maintenance operations are carried out on the unit lock the power supply circuit in the open position ahead of the machine If the work is interrupted always ensure that all circuits are still deenergized before resuming the work ATTENTION Even if the unit has been switched off the power circuit remains energized unless the unit or circuit disconnect switch is open Refer to the wiring diagram for further details Attach appropriate safety labels At least once a year thoroughly inspect the protection devices valves If the machine operates in a corrosive environment inspect the protection devices more frequently 1 3 Repair safety considerations All installation parts must be maintained by the personnel in charge in order to avoid material deterioration and injuries to people Faults an
38. e oil line shutoff valve for circuit to be changed Disconnect the oil inlet line from the compressor 32 vw Remove any remaining refrigerant in the compressor and refrigerant lines by proper reclaiming devices All of the refrigerant that is in the evaporator must be removed if there is no suction service valve installed on the evaporator IMPORTANT Cooling and chilled water pumps must be energized There must be water flowing through heat exchangers whenever adding or removing charge Remove junction box cover of compressor to be changed Check main power leads for marked numbers If no numbers are visible on leads mark leads with appropriate numbers to match those printed on the ends of the terminal lugs This is extremely important as power leads MUST be installed on the exact terminals from which they were removed Disconnect main power leads from compressor terminal lugs Mark remaining control circuit wires connected together with wire nuts for ease of reconnecting later Remove the capacity adjustment SV and oil solenoid valve and high pressure switch from compressor Caution The next steps involve compressor unbolting and removal Compressor seals are made using O rings Use care when removing bolts and disconnecting flanges The O rings must NOT be re used New O rings are provided with the replacement compressor Be sure that an appropriate lifting cart or hoist is used to avoid injury See Fig 31 for lifting methods of scre
39. eason for overheating and eliminate the trouble Running pressure too high Refer to IV and V for refrigerating status refer to VIII and IX for heating status Compressor starts up too freguently Check each automatic adjustment device Refrigerator oil in the compressor not enough Clean the filter sieve 42 APPENDIX C cont Modd LSBLG LSBLG LSBLG LSBLG LSBLG LSBLG LSBLG 340 400 455 540 690 720 825 Items RT 96 7 113 8 129 4 154 2 196 2 204 8 234 6 Nominal Cooling Capacity kW 340 400 455 542 690 720 825 kCal h 292 400 344 000 391 300 466 120 593 400 619 200 709 500 Power input kW 64 0 721 84 7 99 0 121 1 126 0 152 6 Electrical data Rated current A 107 6 121 2 142 4 166 4 203 6 211 8 256 5 Power supply 380 415V 3P 50Hz Capacity control Automatic Capacity steps 96 25 50 75 100 or stepless as option Tvpe Semi hermetic twin screw compressor Starting mode Y A Compressor Quantity 1 1 1 1 1 1 2 Rotate speed rpm 2950 Type R134a Charge kg 210 240 240 240 250 250 360 Refrigerant No of circuits 1 1 1 1 1 1 2 Refrigerant control Orifice baffle EXV Type Shell and tube Pass No 3 3 3 3 3 3 2 Water flow rate m h 69 81 93 110 140 146 168 Condenser Water pressure drop kPa 55 58 60 62 65 68 68 Water side working pressure MPa 1
40. ensor fault Exhaust sensor fault Suction sensor fault Suction Pressure Fault Discharge Pressure Fault 4 Protection items and Troubleshooting 4 1Protection items and Troubleshooting items Protection Purpose High pressure low pressure Ensures the compressor runs in normal range and ensures its work life protection of compressor Converse phase lack of phase Protects the compressor from damage because of converse phase or lack of phase protection of power Anti freezing protection during refrigeration Protects the kev components such as evaporator condenser and water pipe etc from damage because of the expanse caused by the water becomes into ice Overload protection Protects the compressor from burn due to overload running Over current compressor protection of Protects the compressor from burn due to over current running under bad conditions Internal protection Makes the compressor run safely under permitted conditions Anti overheating protection of system Protects the compressor from burn because of running lack of refrigerant or lubricating oil Water flow switch protection Protects the compressor and the water pump motor from burn because there is lack of cooling water or chilled water Protection of sensor fault Ensures the data from sensor is correct to prevent the system from wrong action Oil level and oil pressure Ens
41. essary tLAN or pLAN drive configured not begin to control the valve remains closed Check tLAN pLAN wiring Check that the drive to connect with the pCO application 1f equipped properly manage the drive start signal Check that the drive is not in standalone mode Configured as a stand alone mode the drive does not begin to control the valve remains closed Check the digital input terminal Check that when the control signal input correctly when closed Check that the drive is in stand alone mode LOP protection disabled The LOP integration time is set to greater than 0 seconds LOP protection invalid Ensure that the needs of the LOP protection threshold in the saturation temperature of evaporation evaporation temperature and the rated voltage corresponding to the temperature scale switch between and reduce the LOP integration time Solenoid valve block Check the solenoid valve opens correctly check the electrical wiring and relay operation Lack of refrigerant Check expansion valve upstream of the observation hole no bubbles To ensure proper cooling temperature greater than 5 C or refrigerant filling 212 Valve connection error rotation in the opposite direction and is open And manual control valve is completelv closed or open to check the valve rotation Once the valve is fullv open to allow heat decreased and vice versa so that the superheat values have increased If
42. essor oil Do NOT leave refrigerant system open to air any longer than necessary Seal circuits being serviced and charge with dry nitrogen to prevent oil contamination when timely repairs cannot be completed 20 5 Control 5 1Capacitv Control The unit operation load is controlled bv leaving chilled water The capacitv output of the unit is determined bv the valid length of slide valve which is controlled by 3 solenoid valves The control system cycles compressors loaders and minimum load control valves to maintain the user configured leaving chilled water temperature set point Temperature sensors transfer temperature signals to PLC which will calculate the optimum time to add or subtract capacity stages Special algorithm programmed in PLC will try to maintain the Control Point at the desired set point gt 4 stage control 50 100 The 4 step capacity control system is made of one slider three NC solenoid valves and one piston with adjustable range of 25 50 7590 and 100 The principle of capacity control is by moving the slider to allow partial refrigerant to bypass back to the intake and regulate the refrigerant flow E em lt A Wi L X UE LAT Z gt ON energize OFF de energize 1 Startup 2590 loading For easier startup of compressor the loading must be minimized Therefore SVI is energized to bypass oil to the low pressure side directly The slider does no
43. etely shut down If the superheat value is always low check the electrical wiring and or replacement the valve Often to control the settings in the refrigerated cabinet set Start at the valve opening degree control parameter too High only for composite refrigerated cabinet In all uses are reduced began to control the valve opening degree parameter values make sure to control the temperature will not be affected Liquid only during the defrosting returned to the compressor only Defrosting control after the pause time is too short Increasing the defrosting valve control delay parameter values Defrosting and reaches operating conditions before drive the measured degree of Check and confirm the LowSH threshold is higher than the measured value of the superheat and activate the corresponding protection function integration time 0 applicable to superheat temperature is very seconds When necessary reduced integration time composite low and continued for a few refrigerating minutes cabinet Drive the measured degree of Setting a more sensitive parameter so that the valve can be superheat temperature is not closed the proportion coefficient increases to 30 integral low but there is still liquid time increased to 250 seconds differential time increased to flows back to the compressor 10 seconds unit A plurality of refrigerator and Stagger the defrosting start time If unable to st
44. frigerant Super heat of expansion valve too high Regulate it Ambient temperature too low Check the ambient temperature if necessary turn off some fans Inspiration pressure too low Refer to VI IV Discharge pressure too high refrigerating status Too much Refrigerant Draw out proper amount of Refrigerant Incondensable gas enters Exhaust the gas Fin heat exchanger is dirty Clean the fin heat exchanger Temperature of the fin heat exchanger is high Check the ambient temperature of fin heat exchanger and whether there is some obstacles affect the supply air rate Supply air not enough for the fin heat exchanger Check the operation status of the Fan High pressure gauge not accurate Change a new high pressure gauge Suction pressure too high Refer to V 41 V Suction pressure too high refrigerating status Refrigeration load too large Regulate it Super heat of expansion valve too OW Regulate it Too much refrigeration Draw out proper amount of refrigeration media VI Suction pressure too low refrigerating status Refrigeration media not enough Add refrigeration media Dry filter blocks Clean it or change another filter sieve Refrigeration load too small Regulate it Cooling water not enough Regulate it Cooling water filter blocks Clean it
45. g Heat Exchangers Check the chiller tightness and whether there s leak of heat exchange tubes It is necessary to do nondestructive inspection for the principal weld longitudinal and circumferential weld of evaporator condenser barrel of pressure vessel Inspect and clean cooler tubes at the end of the first operating season Tube condition in the exchanger will determine the scheduled frequency for cleaning and will indicate whether water treatment is adequate in the water circuit Too much scale will cause big loss of capacity and efficiency 28 Refer to the following pressure temperature curve for condition in heat exchangers High pressure cooling water temperature high pressure beyond 0 6 1 2MPa is abnormal ES a 18 o M o E E 12 14 s a a ce iy The more the scale on iei goa o condenser the high the gt qis 8 5 jill be 5 y s 8 10 pressure wil E 10 SS 2 SS o o amp amp 6 T 6 20 22 24 26 28 30 32 34 36 20 25 30 35 40 Leaving cooling water temp C Leaving cooling water temp C Fig 26 High pressure at full load standard unit Low pressure chilled water temperature low pressure beyond 0 14 0 37MPa is abnormal 5 at o o Kol E E S o o gi 2 2 2 2 g 3 8 2 a a 2 2 This area should be cleaned al 2 d 1 5 T 9 11 13 15 5 10 15 Leaving chilled water temp C Leaving chilled water temp C Fig 27 Low pressure at full load standard unit Cleaning work must be done when
46. g area unloading area shut down Abbreviation Ts leaving chilled water temp set point Tout actual leaving chilled water temp To temperature setting range In fuzzy loading area PLC judges the temperature changing trend if it rises up execute the loading progress Else stay in initial state Similarly in fuzzy unloading area PLC judges the temperature changing trend if it goes down execute the unloading progress Else stay in initial state For dual heads unit when executing capacity control program one compressor keeps full load while another one unloads to 50 load Then unload the full load one until it unloads to 50 and shut the compressor of both 50 load which has run for a longer time If the running compressor loads to 100 again start another one When chilled water temperature gets lower than 4 C chiller will stop When it rises up to 13 C chiller restarts If both the compressors are stopped when restarting first on unit must meets requirement of reset temperature set point If Tout gt 9 C and first compressor is in full load the other compressor will start When dual compressor unit is in suspending state and Tout gt 18 C the unit will start according to first time Operation program after both compressors meet the min stopping interval When both compressors operating in 5090 load is in loading area and fuzzy loading area the compressor which has run for less time loads first When both compressors operat
47. h pressure gauge can not indicate precise figure Insufficient cooled water Strainer of cooled water is blocked Expel some refrigerant Expel the air Check it and do reparation Repair it Do cleaning Replace a new gauge Replenish the water Do cleaning Suction pressure is too high Chilling overload Low degree of superheat of expansion valve Excessive refrigerant Adjust the load Adjust it Expel some refrigerant Suction pressure is too low Insufficient refrigerant Blocked by desiccant Chilling load is too low Check the leakage and add the refrigerant into the unit Insufficient chilled water Strainer of chilled water is blocked Replace and clean the filter Adjust the load Replenish the water Do cleaning Capacity adjusting device failure Thermostat failure Solenoid valve is damaged Capillary tube is blocked Replace it with a new one Replace it with a new one Do cleaning Compressor Defective bearing of compressor Replace the compressor overheat Over high pressure on liquid side Refer to item 4 Temp and pressure of refrigerant on gas Adjust the pressure on gas side and the side is unfolding too high degree of solenoid valve Electromotor is overheated Refer to item 10 NFB Escape Short circuit of wiring Measure the insulation resistance Wiring is grounded Electromotor of compressor failure Ditto
48. igured not begin to control the valve remains closed Check tLAN pLAN wiring Check that the drive to connect with the pCO application if eguipped properly manage the drive start signal Check that the drive is not in standalone mode Configured as a stand alone mode the drive does not begin to control the valve remains closed Check the digital input terminal Check that when the control signal input correctly when closed Check that the drive is in stand alone mode 13 cabinet 4 3EXV operation and wiring Displav User interface consists of five components of the LED displav operating status the table below LED Light Extinguish Flicker NET Can be connected to the network Not connected Communication failure OPEN Open the valve Disable the drive CLOSE Close the valve Disable the drive Activate the alarm The drive is not connected to power Drive power supply Display board installed optional Screen after installation can be used to configure the drive and its programming The display shows the operating status drive type of control is being performed such as superheat control alarm digital input and relay output status of the state of important parameters Finally it can save the configuration parameters of a drive and copy to another drive transfer Installation steps Press and hold fastening fastener remove the cover nstall s
49. in with soap and water If liquid refrigerant enters the eyes immediately and abundantly flush the eyes with water and consult a doctor Never apply an open flame or live steam to a refrigerant container Dangerous overpressure can result If it is necessary to heat refrigerant use only warm water Do not re use disposable non returnable cylinders or attempt to refill them It is dangerous and illegal When cylinders are empty evacuate the remaining gas pressure and move the cylinders to a place designated for their recovery Do not incinerate Do not attempt to repair or recondition any safety devices when corrosion or build up of foreign material rust dirt scale etc is found within the valve body or mechanism If necessary replace the device Do not install safety valves in series or backwards Ensure that you are using the correct refrigerant type before recharging the unit Charging any refrigerant other than the original charge type R 134a will impair machine operation and can even lead to a destruction of the compressors The compressors operating with this refrigerant type are lubricated with a synthetic ATTENTION No part of the unit must be used as a walkway rackor support Periodically check and repair or if necessary replace any component or piping that shows signs of damage The refrigerant lines can break under the weight and release refrigerant causing personal injury Do not climb on a machine Use a platform or staging
50. ing in 5090 load is in unloading area and fuzzy unloading area the compressor which has run for longer time unloads first Notes all parameters in this part are based on standard condition leaving chilled water temp 79C entering cooling water temp 35 C Stepless control 25 50 22 Solenoid valve activating table of stepless control ON energize OFF de energize The principle of linear capacity control system is same as four step one except that the control logic of solenoid valve varies The four step capacity control needs three NC normal close solenoid valves whereas the linear one uses two NC normal close solenoid valve to control the increase or decrease of loading When starting compressor SV1 is energized to bypass the oil in hydraulic cylinder back to the low pressure
51. ion with ordinary measuring coil resistance tester Two coil resistance should be around 36 Euro Otherwise replace the stator Finally check the cable connection to connect the drive Valve can not open Started using the manual control valve fully open If the superheat value is still high check the electrical wiring and or replace the valve Even if the valve is fully opened refrigerated cabinets also reach the set temperature only for composite refrigerated cabinet Solenoid valve block Check the solenoid valve opens correctly check the electrical wiring and relay operation Lack of refrigerant Check expansion valve upstream of the observation hole no bubbles To ensure proper cooling temperature greater than 5 C or refrigerant filling Valve is too small Replaced with a larger valve Valves damaged or connected incorrectly the stator The stator and the valve and disconnect the cable connection with ordinary measuring coil resistance tester Two coil resistance should be around 36 Euro Otherwise replace the stator Finally check the cable connection to connect the drive Valve can not open Started using the manual control valve fully open If the superheat value is still high check the electrical wiring and or replace the valve Freezers reach the set temperature and the valve position is always O step only for composite refrigerated tLAN or pLAN drive conf
52. ld be over 5MO when measuring with ohmmeter of DC 500V When touching the shockproof rubber it should be elastic or it means the rubber gets ageing Every 3000 hours make middle inspection of vibration and oil level every 6000 hours check the safety device and protective device to guarantee the normal operation Important The normal oil level is at the middle of sight glass Adding lubricating oil if the oil level decline obviously Inspect the oil quality monthly to see 1f there s dirt or deterioration otherwise replace the oil and filter core if necessary by specialized technicians Make chemical analysis of the lubricating oil if emulsification phenomenon occurs change the oil of same brand Heat exchangers Adjust the water flow to keep the high low pressure within normal range high pressure 0 6 1 2MPa low pressure 0 1 0 4 If the temperature difference between leaving cooling water temperature and refrigerant temperature in condenser is larger than 6 C it means the condenser is scaling and cleanness work is in urgent need When the chiller stops for a long time water in heat exchangers and pipe system should be drained thoroughly For newly installed chiller the filters in water system should be cleaned after running for 24 hours and then clean the filters quarterly Valves and pressure controllers A Safety valves Inspect the integrity and performance of valves every year The maintenance of safety valves should be done by speci
53. m the steps below to solve the problem 1 Check to confirm that all strainers are clean valves are open and pumps are running For the case of VFD controlled pumps ensure that the minimum frequency set point has not been changed 2 Measure the pressure drop across the heat exchangers Read the difference of pressure gauges installed on the inlet and outlet and using Appendix water pressure drop curves calculate the flow and compare this to the system requirements 24 3 If the measured flow rate through the heat exchanger agrees with the svstem requirements Possible reason of the malfunction may be wrong installation direction of the switch inadequate depth of the target broken switch or wiring looseness etc New switch must be replaced if problem is switch itself 5 50il Heater Control I n unit shutdown period oil heater is energized to keep normal oil temperature When unit starts it is turned off Oil heating time limits 1 When cooling water inlet temperature gt 35 C real time value oil heating time for first startup is 0 5h If power down happens during operation and downtime is less than 8hrs no heating time delay is needed when unit restarts If it exceeds 8hrs 0 5h heating time is need 2 When cooling water inlet temperature gt 30 C real time value oil heating time for first startup is 1h If power down happens during operation and downtime is less than 5hrs no heating time delay is needed when unit restart
54. mbalance is greater than 2 Contact local Utility for assistance 9 Verify cooler flow rate maximum and minimum Entering chilled water pressure psig kPa Leaving chilled water pressure psig kPa Chilled water pressure drop psig kPa Psig x 2 31 ft psi ft of water kPa x 0 334 m psi m of water Maximum chilled water flow rate ______ gpm l s Minimum chilled water flowrate gpm Vs III Unit Start Up cont Verify condenser flow rate Entering cooling water pressure psig kPa Leaving cooling water pressure psig kPa Cooling water pressure drop psig kPa Psig x 2 31 ft psi ft of water kPa x 0 334 m psi m of water Cooling water flow rate gpm l s Start and operate machine Complete the following 1 Complete component test 2 Check refrigerant and oil charge Record charge information 3 Record compressor motor current 4 Record two sets of operational log readings 5 Provide operating instructions to owner s personnel Instruction time hrs Refrigerant Charge Circuit A Circuit B Additional charge required Oil Charge Additional charge required Comments 57 Signatures Start up Technician Customer Representative Date Date 58
55. mmediately according to abnormal protective shutdown program After the switch reset fault on screen must be confirmed and cleared manually when both temperature and time condition gets satisfied the chiller can restart High discharge temperature protection Discharge temp gt 60 C perform high discharge temperature protection Faulted compressor stops immediately to abnormal protective shutdown program and other normal system will keep on running The protection resets when temperature gets lower than 45 C and should be confirmed and cleared manually when both temperature and time condition gets satisfied the chiller can restart Comp OFF 60 C 60 C Comp ON Overhigh leaving cooling water temp When leaving cooling water temp is higher than 45 C during unit operating the chiller will stop immediately according to abnormal protective shutdown program Reset at 38 C and it needs to be confirmed and cleared manually when both temperature and time condition gets satisfied the chiller can restart Overcurrent protection of compressor The protection trips when compressor current gt set point Faulted compressor will stop immediately to abnormal protective shutdown program and other normal system will keep on running After the switch reset fault on screen must be confirmed and cleared manually when both temperature and time condition gets satisfied the chiller can restart Current transducer protection When current transducer ope
56. n Protection of phase loss phase DI22 2 Compressor protection NC unbalance phase reversal over high Delayed malfunction detection discharge temp DI 23 2 Oil level protection NC In case of lacking of oil Open circuit 3s activate Determine by DI 24 2 Overload protection electric control Discharge pressure protection Delayed malfunction detection DI25 2 Phase protection NC Power protection Delayed malfunction detection DI 30 Reserved AIOI Entering chilled water temp Analog Sub cooling capacity control 0 50 C precision 0 1 C AI 02 Leaving chilled water temp Analog Capacity control 0 50 C precision 0 1 C AI 03 Entering cooling water temp Analog Temp detection 0 50 C precision 0 1 C AI 04 Leaving cooling water temp Analog Temp detection 0 50 C precision 0 1 C AI 05 Discharge 1 Analog Temp detection 0 150 C precision 0 1 C AI 06 Discharge 2 Analog Temp detection 0 150 C precision 0 1 C AI07 Current transducer 1 Analog Current detection 0 500A only for stepless unit 46 A108 Current transducer 2 Analog Current detection 0 500A only for stepless unit AI 09 Oil temperature 1 Analog Temp detection reserved 0 100 C precision 0 1 C AI 10 Oil temperature 2 Analog Temp detection reserved 0 100 C precision 0 1 C Output signal Code Description Type Function Remarks DO 00 Chilled wate
57. n circuit or short circuit happens compressor will stop immediately to abnormal protective shutdown program and current transducer fault is displayed on screen Other normal system will keep on running After the switch reset fault on screen must be confirmed and cleared manually when both temperature and time condition gets satisfied the chiller can restart Note Refer to APPENDIX A for detailed troubleshooting All these work must be done by professional technicians who are qualified to do so 27 6 Service 6 1Servicing Evaporator And Condensers gt TUBEPLUGGING In order to do maintenance when convenient a leakv tube can be plugged until retubing can be done if damaged tubes are not too manv The number of tubes plugged determines how soon the evaporator must be retubed Plugging tubes will result in loss of capacitv and efficiencv as well as increased pump power Failed tubes should be replaced as soon as possible Up to 109 of the total number of tubes can be plugged before retubing is necessarv If the problem is much more serious contact vour local Midea or vour local representative for assistance Caution Use extreme care when installing plugs to prevent damage to the tube sheet section between the holes RETUBING Retubing must be done bv qualified personnel experienced in boiler maintenance and repair Most standard procedures can be followed when retubing the evaporators Place one drop of Loctite or equivalent on top of
58. n increasing the integration time by the same proportion In corresponding to the average any case the recommended use of stable system parameters work the superheat value is no longer swing Superheat setting is too low Increase the superheat setting check to make sure superheat swing has been reduced or disappeared Set the start of 13 C and then gradually reduce the set value to ensure that the system does not swing again and the device temperature can be set to control value In the MOP protection disabled or The MOP threshold is set to require saturated evaporation evaporating invalid temperature high evaporation temperature limit compressor temperature and MOP integration time set between the National Cheng higher start up Kung University in O recommended for 4 seconds to phase the activate the MOP protection To make the protection more evaporation sensitive down MOP integration time low pressure is too high Start system or transient conditions excess refrigerant charge for refrigerator A soft start a time to start a facility or a group If this method is not feasible to reduce all the facilities of the MOP threshold Low start up phase protection function activated only comes with the compressor equipment Parameter start control valve opening degree set too low Reference to the evaporator cooling capacity and rated capacity of the valve than check this parameter value increase this value if nec
59. n screw compressor Starting mode Y A Compressor Quantity 2 2 2 2 2 2 2 Rotate speed rpm 2950 Type R134a Charge kg 380 400 400 420 440 440 440 Refrigerant No of circuits 2 2 2 2 2 2 2 Refrigerant control Orifice baffle 4 EXV Type Shell and tube type Condenser Pass No 2 2 2 2 2 2 2 Water flow rate m h 185 202 225 243 264 280 293 44 Water pressure drop MPa 70 72 75 78 80 82 85 Water side working pressure kPa 1MPa Higher pressure can be customized mm DN150 DN200 DN200 DN200 DN200 DN200 DN200 Pipe connections in 6 8 8 8 8 8 8 Tvpe Flooded tvpe Pass No 2 2 2 2 2 2 2 Water flow rate m h 157 172 191 206 224 238 249 Water pressure drop kPa 68 70 72 75 77 80 82 Evaporator Water side working pressure MPa 1MPa Higher pressure can be customized mm DN150 DN200 DN200 DN200 DN200 DN200 DN200 Pipe connections in 6 8 8 8 8 8 8 Length mm 4500 4600 4600 4600 4600 4600 4600 Dimension Width mm 1600 1700 1700 1700 1700 1700 1700 Height mm 1900 2100 2100 2100 2100 2100 2100 Shipping weigh kg 6000 6600 6800 7000 7200 7400 7500 Operating weight kg 6500 7150 7350 7600 7850 8050 8150 Notes 1 All parameters are under standard condition Entering leaving chilled water temperature 12 7 C Entering leaving cooling water temperature 30 35 C Fouling factor is 0 086 m C kW 2 Specifications
60. n the suction superheat suction superheat to adjust through the electronic expansion valve opening so that the unit run at a steady state energy 2 3Compressor Protection module Compressor winding test temperature and exhaust temperature if the temperature is too high it will protect and alarm 2 4Emergency Stop Switch Downtime in the event of an emergency you can press this button to immediately stop 3 OPERATION DATA 3 1Electronic Expansion Valve EXV EXV OPERATION High evaporation temperature alarm delay MOP High condensing temperature alarm delay HiTcond Low suction temperature alarm threshold Low suction temperature alarm delay EEV minimum number of steps EEV Maximum number of steps EEV step off Rated speed of EEV Rated current EEV EEV guiescent current EEV duty Open simultaneous localization Closed simultaneous localization Compressor Protection Module OUTPUTS 220V Machine protection switch Exhaust temperature thermal switch INPUTS Three phase power 380V 3P 50Hz Star Delta Startup Reduce the starting current to avoid the high current motor start transient impact 3 2Alarms Alerts Evap flow alarm Freeze Alarm High pressure alarm Low pressure alarm Delta pre alarm Compressor fault Oil level alarm Oil press diff Contactor fault Compressor overload Power Failure Exhaust temp high Fin temp high Water out sensor fault Water in sensor fault Fin sensor fault Environmental s
61. ndenser leaving water temperature to be in 0 2 3 C range e The evaporator refrigerant level slightly laps last tubes row by checking the sight glass installed on each evaporator for a visual inspection f The condenser refrigerant level to be included between the condensing and the sub cooling sections by checking the sight glass installed on each condenser for a visual inspection 5 Verify the sight glass on the liquid piping to be fully charged If one of the above parameters exceeds the limits unit may require an additional refrigerant charge Note Refrigerant removing and drain operation must be performed by qualified personnel using correct material Inappropriate maintenance could lead to refrigerant or pressure loss Do not discharge the refrigerant or the lubricant oil into the environment Always use a proper recovery system Refer to Physical Data tables supplied in the IOM manual book Immediately ahead of orifice baffle see Fig is a factory installed liquid line service angle valve Each angle valve has al 5 8 in threaded connection for charging liquid refrigerant Connect the refrigerant drum to the gauge port on the liquid line shutoff valve and purge the charging line between the refrigerant cylinder and the valve Then open the valve to the mid position Turn on both the cooling tower water pump and chilled water pump and allow water to circulate through the condenser and the chiller IMPORTANT When adding refrigerant to the
62. ng Low Oil Recharging gt Pre cautions in changing of oil 1 Use only qualified oil and do not mix different brand of oil together Different kinds of refrigerant should match different kinds of oil note that some synthetic oil is incompatible with mineral oil 2 When using the synthetic oil for the chiller system be sure not to expose the oil to atmosphere for a long time it is also necessary to vacuum the system completely when installing the compressor 3 In order to ensure no moisture inside the system it is suggested to clean the system by charging it with dry Nitrogen and then vacuum the system repeatedly as long as possible 4 It is essential to change for new oil especially after the motor burns out the acidity debris still remain inside the system so clean work must be done to overhaul the system Check the oil acidity after 72 hours of operation and then change it again until the oil acidity is in the standard value 5 Contact local distributor agent for concerning unqualified oil to be used gt Oil change 31 1 Change oil periodicallv Check the lubrication oil for everv 10 000 hours of continuous running For the first operation of the compressor it is recommended to change oil and clean oil filter after running at 2 000 hours Check the svstem whether clean or not and then change the oil everv 20 000 hours or after 3 vears of continuous running while the system is operated under good condition 2 Avoid the debris or s
63. oe RG HES NGR 5 3 Pump control 5 4 Cooler and Condenser Pump Contro esses ener ennt nnne An en nene innen nein nenne 5 5 Oil Heater Control 5 6 Protection Items And Troubleshooting esee eene nennen entente nnne en nennen nennen nene 6 Service 6 1 Servicing Evaporator And Condensers eene nennen 6 2 Inspecting Cleaning Heat Exchangers seren ern nn nn ranet nanna nanna tt 6 3 Water Treatment 6 4 Refrigerant CIrCUl oerte A t an RL AAA RA E O Compressor Dil System rete di a a ge 6 6 Oil recovery Syste Msia e AAA AAA AA 6 7 Oil Charging Low Oil Recharging ana tan anna Anna enn seen snnt 6 8 Oil Filter Maintenance iii a iu idee enirn tne hb cene rni herd da Re epa eerie x ahisi nea di ki das 6 9 Compressor Change out Sequence ooooocccnncnnonanononannnannnnnnono nono nono nono eene nnne 6 10 Safetv DEVICES iii tio t a Re vel aab qa Loh ba n de CYFR estes 7 Maintenance e e ud d Nee ei ee old ete UG UG Giese Operation CHECKS fit acess testes te irte t eter eto v a rentes rt 7 2 Recommended maintenance schedule eese nennen nnne en nn rn anar 1 3 Chilled water cycling Eee T ee Oo ee EGRE E e CR a e PU a as J A ElectricalcontrolsySteri ceteri Ai tus Yee ea WWF FFYDD NN EYE ea un AR AE 8 APPENDUX qe A H Sal Field WISE ii ia di A va cade ba B a A a a a b abi 2 T rouble skOottfi i li er etre AA dadas 8 3
64. of the control board or accompanying wiring may destroy the electronic modules or electrical components Warning To prevent potential damage to heat exchanger tubes always run fluid through heat exchangers when adding or removing refrigerant charge or when the equipment is exposed to temperatures below 32 F 0 C DO NOT VENT refrigerant relief valves within a building Outlet from relief valves must be vented outdoors in accordance with the latest edition of ANSI ASHRAE American National Standards Institute American Society of Heating Refrigeration and Air Conditioning Engineers 15 Safety Code for Mechanical Refrigeration The accumulation of refrigerant in an enclosed space can displace oxygen and cause asphyxiation Provide adequate ventilation in enclosed or low overhead areas Inhalation of high concentrations of vapor is harmful and may cause heart irregularities unconsciousness or death Misuse can be fatal Vapor is heavier than air and reduces the amount of oxygen available for breathing Product causes eye and skin irritation Decomposition products are hazardous Warning DO NOT attempt to cut factory joints when servicing this equipment Compressor oil is flammable and there is no way to detect how much oil may be in any of the refrigerant lines Cut lines with a tubing cutter as required when performing service Use a pan to catch any oil that may come out of the lines and as a gage for how much oil to add to system DO NOT re use compr
65. or improperly treated water 51 2 2 1 1 2 2 APPENDIX H Midea LSBLG Water Cooled Screw Chiller Maintenance Data Log PLANT CHILLER MODEL NO CHILLER SERIAL NO Remarks Any other operation such as repairs made accessory parts changed oil or refrigerant added or removed including amounts 53 APPENDIX I 8 6Start Up Checklist for Midea Screw Chiller I Project Information Job Name Address Citv State Zip Installing Contractor Sales Office Start up Performed Bv Design Information lapacity WT WT luid type low Rate ooler ondenser Equipment Equipment Vlodel Model jerial berial Lompressors Compressors ff Model ff Model jerial berial Model it Model Serial Serial Cooler Cooler Vlodel Model jerial berial 54 Condenser Condenser Vlodel Vlodel jerial berial II Preliminary Equipment Check to be completed by installing contractor Is there any physical damage Yes__No__ Description 1 Unit is installed level as per the installation instructions Yes No 2 Power supply agrees with the unit nameplate Yes No 3 Correct control voltage vac Yes No 4 Electrical po
66. osed or open to check the valve rotation A fullv open valve Superheat can be decreased and vice versa so that the superheat values have increased If the valve is rotating in the opposite direction check electrical wiring Superheat setting is too low Check superheat setting Beginning to set 12 7 C check to make sure there is no return of liquid Then graduallv reduce the set value but alwavs returning to ensure that no liquid Low superheat protection is invalid If low superheat value of long duration and the valve closes slowlv then increase the degree of protection of low superheat threshold and or protection to lower superheat integration time The beginning of the threshold value is set lower than the superheat setting 3 C points time is set to 3 4 seconds Low heat and then graduallv reduce the threshold and increase the integration time check to make sure the under anv operating conditions there was no return of liquid Valves damaged or connected incorrectiv the stator The stator and the valve and disconnect the cable connection with ordinarv measuring coil resistance tester Two coil resistance should be around 36 Euro Otherwise replace the stator Finallv check the connection of electric drive cable wiring Valve can not close Always check the superheat value is too low lt 2 C and the valve position is always O step If the above situation the valve is set to manual control and compl
67. parameters Cooling tower fan ON temp 27 18 270 Commissioning parameter Cooling tower fan OFF temp 25 18 250 Commissioning parameter Oil supply SV Time delay of oil return SV ON 2s 1 5s Time delay of oil return SV OFF 300s 200 5000 Stepless control unit Description Default Setting range Remarks User parameters Leaving chilled water set point Ts TC 7100 User parameter Mode selection Cooling Cooling pump User parameter A8 Compressor parameters Min shut down interval of comp 15s 10 15s Commissioning parameter Min running time of comp 15s 10 15s Commissioning parameter Startup interval of comp 25s 25 30s Plant parameter Oil heating time 30s 0 120s Commissioning parameter Capacity adjusting parameters Unload SV ON time 1 0s 0 5 1 5s Plant parameter Unload SV OFF time 15s 10 20s Plant parameter Load SV OFF time 1 5s 0 5 2s Plant parameter Load SV ON time 15s 10 20s Plant parameter Alarm parameters Low pressure protection delay 3s 0 6s Plant parameter Oil level alarm delay 60s 0 120s Plant parameter 1 compressor over load current Depending on unit model 100 500A Plant parameter 2 compressor over load current Depending on unit model 100 500 A Plant parameter Discharge temp protection point R134a 60 C 60 75 C Commissioning parameter Discharge temp protection reset point R134a 45 C 40
68. perature and time condition gets satisfied the chiller can restart Discharge temperature sensor short circuit open circuit display discharge temperature fault and chiller stops according to abnormal shutdown program After the sensor reset fault on screen must be cleared manually when both temperature and time condition gets satisfied the chiller can restart gt Over under voltage When power supply voltage is less than 9096 or more than 11096 corresponding alarm over voltage or under voltage occurs The chiller will stop immediately according to abnormal shutdown program Fault on screen must be cleared manually when both temperature and time condition gets satisfied the chiller can restart High low pressure protection Alarm as soon as high pressure switch trips and stop the chiller immediately according to abnormal shutdown program It is one kind of NC switch and needs manual reset of the red reset button when fault happens Fault on screen must be confirmed and cleared manually when both temperature and time condition gets satisfied the chiller can restart When suction pressure is lower than the protective low pressure set point effective for time delay stop according to abnormal shutdown program After the switch reset fault on screen must be confirmed and cleared manually when both temperature and time condition gets satisfied the chiller can restart Anti freeze protection Over low leaving chilled water temperature When le
69. r pump Valid for ON Control chilled water pump DO 01 Chilled water pump Valid for ON Control cooling water pump DO 02 Cooling tower fan Valid for ON Improve the cooling effect DO 10 1 Ff alarm Valid for ON Alarm when protection or fault occurs DO 11 1 start stop control Valid for ON start stop control of compressor DO12 1 25 SV Valid for ON Control 2590 SV Startup SV for stepless unit DO13 1 50 SV Valid for ON Control 5096 SV Unload SV for stepless unit DO 14 14 75 SV Valid for ON Control 75 SV Load SV for stepless unit DO 15 1 oil supply SV Valid for OFF Close 1 oil slip DO 16 1 throttle bypass valve Valid for ON Open Road 1 fluid DO 17 1 operating indicator Valid for ON 1 operating indicator of compressor DO 20 2 start stop control Valid for ON start stop control of compressor DO 21 2 25 start stop control Valid for ON Control 25 SV Startup SV for stepless unit DO 22 2 50 start stop control Valid for ON Control 50 SV Unload SV for stepless unit DO 23 2 7590 start stop control Valid for ON Control 75 SV Load SV for stepless unit DO 24 2 oil supply SV Valid for OFF Close 2 oil slip DO 25 2 throttle bypass valve Valid for ON Open Road 2 fluid DO 26 2 operating indicator Valid for ON 2 operating indicator of compressor DO27 2H alarm Valid for ON Alarm when protection or fault occurs DO 30 reserved 47 APPENDIX E cont Configurable parameters 4 stage control unit
70. recognized that atmospheric air contains manv contaminants that increase the need for proper water treatment The use of untreated water can result in corrosion erosion sliming scaling or algae formation It is recommended that the service of a reliable water treatment company be used 6 Remove condenser heads at least once a year to inspect the condenser tubes and clean if required 7 2Recommended maintenance schedule This chapter shows the preventive maintenance of Midea screw chiller Correct maintenance and timely service will make the chiller in the best condition and with best performance beside it can prolong the lifespan of chiller The customer has responsibility to appoint qualified equipment management engineer and specially assigned operator to do the daily and scheduled maintenance The repair work should be done by big maintenance agency that is qualified to do the job It s better to make maintenance agreement with local customer service centre of Midea after chiller out of warranty to keep the chiller always under effective service and guarantee reliable operation Note Repair work caused by incorrect maintenance within warranty will lead to extra charges gt Daily maintenance The basic work of unit maintenance is to truly record the operation parameters of unit at certain intervals e g 2hours everyday Fill the operation parameter table which contains such key parameters as high low pressure suction discharge temperature
71. s If it exceeds 5hrs 1h heating time is need 3 When cooling water inlet temperature gt 25 C real time value oil heating time for first startup is 2hrs If power down happens during operation and downtime is less than 3hrs no heating time delay is needed when unit restarts If it exceeds 3hrs 0 5h heating time is need If it exceeds 5hrs 2hrs heating time is need 4 When cooling water inlet temperature gt 20 C real time value oil heating time for first startup is 4hrs If power down happens during operation and downtime is less than 1h no heating time delay is needed when unit restarts If it exceeds 1h 2hrs heating time is need If it exceeds 5hrs 3hrs heating time is need If it exceeds 8hrs 4hrs heating time is need 5 When cooling water inlet temperature 20 C real time value oil heating time for first startup is 8hrs If power down happens during operation and downtime is less than 1h no heating time delay is needed when unit restarts If it exceeds 1h 3hrs heating time is need If it exceeds 5hrs 5hrs heating time is need If it exceeds 8hrs 8hrs heating time is need Demand Limit Auto unload control function For step control unit When compressor continuously operates at chilled water temperature gt 12 C more than 30 mins unload to 509 regain 10090 load after 10 mins later For stepless control unit When compressor continuously operates at chilled water temperature gt 12 C more than 30 mins unload to
72. s cool energize oil heaters and allow 8 hours for heater to remove refrigerant from the oil before starting Check and tighten all electrical connections Replace the drain plug in the cooling tower pump if it was removed at shutdown time the previous season Install fuses in main disconnect switch if removed Reconnect water lines and turn on supply water Flush condenser and check for leaks UB un Annual Shutdown Where the chiller can be subject to freezing temperatures the condenser and chiller must be drained of all water Dry air blown through the condenser will aid in forcing all water out and decreasing the corrosion Water permitted to remain in the piping and vessels can rupture these parts if subjected to freezing temperature If the chiller is used in areas where the ambient temperature will fall below 0 C forced circulation of antifreeze through the water circuits is one method of avoiding freeze up 1 Take measures to prevent the shutoff valve in the water supply line from being accidentally turned on 2 Ifa cooling tower is used and if the water pump will be exposed to freezing temperature be sure to remove the pump drain plug and leave it out so any water that can accumulate will drain away 3 Open the compressor disconnect switch and remove the fuses 4 Check for corrosion and clean and paint rusted surfaces 37 5 Clean and flush water tower for all units operating on a water tower It should be
73. s in initial state 5 3 Pump control Water pump mode When user has selected water pump mode PLC receives operation signal and turn on chilled cooling water pump without starting the compressor Chilled cooling water flow switch is valid and its detection method is the same with normal startup procedure In pump mode if user chooses cooling mode when chilled water temperature is low and not enough to start the chiller both chilled cooling water pumps keep on running until leaving chilled water temperature condition gets satisfied Note In pump mode it can transfer to cooling mode directly in cooling mode it needs to stop the unit and pumps first then transfer to pump mode When accumulative total running time reaches 3 600 000s remind user servicing water system and performing scheduled cleaning work 5 4Cooler and Condenser Pump Control Midea chillers can be configured for cooler and condenser pump control Inputs for a cooler pump interlock and condenser flow switch or interlock are provided Refer to appendix for details gt Cooler pump control Proper configuration of the cooler pump control is required to prevent possible cooler freeze up A cooler flow switch must be installed on the outlet of chilled water to prevent operation without flow through the cooler The chiller is also interlocked with the chiller water pump starter to provide additional protection See appendix of the Field Wiring section for proper connection of the
74. sor l d LY Sight glass RG A 9 lt 0 Filter m Solenoid valve RL 8 MI gt d Ejector x Ppa Cutvalve ES Throttling orifice Evaporator mA tl Condenser 7 Hihii itch E A T igh low press switc F y de mal T m High low pressure switch x rur EXV fh RL EXV I A g A 1 a a am co EE Fix Ex A Oil Ei 3 rey Oi eparato T fn E eparato Bvap ik Cond i 1 gt 50 APPENDIX G 8 5Midea s recommendations on heat exchange fluids 1 No NH4 ammonium ions in the water they are very detrimental for copper This is one of the most important factors for the operating life of copper piping A content of several tenths of mg l will badly corrode the copper over time 2 Cl Chloride ions are detrimental for copper with a risk of perforations by corrosion by puncture If possible keep below lt 50ppm 3 SO42 sulphate ions can cause perforating corrosion If possible keep below lt 50ppm 4 No fluoride ions lt 0 1 mg l 5 If possible keep Calcium ion below lt 50ppm 6 No
75. suction end while SVO is de energized Slider remains in its initial position due to the spring force and then the compressor can be sure to start at 2590 loading Once the startup process is completed SVO is energized while SV1 1s de energized to increase the loading up to 100 To keep compressor running in steady state SVO SVI is de energized continuously to maintain the stable refrigeration capacity output Once loading has been changed the system energizes de energizes of SVO and SV1 to adjust output of compressor in order to fit actual loading requirement When loading increases SVO energizes shortly to allow small amount of oil to flow into hydraulic cylinder and force slider to move in the direction of increasing refrigeration capability If loading decreases SVI energizes shortly to allow small amount of oil to flow out of hydraulic cylinder and cause slider to move in the direction of decreasing the refrigeration capabilitv 5 2Head Pressure Control General For Midea screw chiller it adopts professional PLC controller to maintain the saturated condensing temperature to a configurable set point Cooling tower fan is controlled by the return water temperature During compressor startup and operating progress cooling tower fan is OFF when entering cooling water temperature 25 C When entering cooling water temperature gt 279C cooling tower fan is ON When entering cooling water temperature is between 25 27 C cooling tower fan keep
76. t move and keep the maximum opening in suction end to bypass the refrigerant After the completion of startup the compressor then can increase loading gradually by de energizing the SVI solenoid valve It is recommended to run compressor at 2590 loading for about 30 seconds before starting to increase loading 2 Partial load 50 Operation With the same principle as stated in 2590 loading SV2 is engergized and others are de energized to achieve 5090 loading 3 Partialload 75 Operation Receiving a feedback from system demanding for lower capacity the SV3 is energized to allow oil to flow back to the low pressure side through the valve channel The piston returns to the outlet of SV3 oil passage and the slide 21 block moves to let part refrigerant flow back to the low pressure side through bvpass opening This action would reduce the discharge volume and make the compressor operating at 7590 loading 4 Full load 100 operation After the completion of startup SV1 SV2 and SV3 are de energized and oil flows straight to cylinder and pushes piston forward driving the slider to gradually reduce bypass opening When the opening is closed completely the compressor is running at 100 loading Operation progress of stage control Take standard condition leaving chilled water temp 7 C entering cooling water temp 357C for example There are 6 sections of capacity adjusting progress loading area fuzzy loading area stable area fuzzy unloadin
77. to Installation Instructions for proper cooler winterization procedure 9 Outdoor piping wrapped with electric heater tape Yes No 10 Cooler heaters installed and operational Yes No 11 Cooler heads and tube sheets are insulated Yes No Cooling Water System Check 1 All condenser water valves are open Yes No 2 All piping is connected properly Yes No 3 All air has been purged from the system Yes No 4 Condenser water pump is operating with the correct rotation Yes No 5 Condenser water pump controlled by chiller Yes No 6 Inlet piping to condenser includes a water strainer Yes No 7 Cooling water flow switch has been installed Yes No 8 Cooling water flow switch has been configured and operational Yes No 9 Cooling water control valve has been installed Yes No III Unit Start Up 1 All liquid line valves are open Yes No 2 All discharge valves are open Yes No 3 AII suction service valves are open if equipped Yes No Yes No 56 Yes No 4 All oil line valves are open 5 Chilled water flow switch is operational 6 Leak check unit Locate repair and report anv refrigerant leaks Yes No 7 Voltage is within unit nameplate range Yes No 8 Check voltage imbalance A B A C B C Average voltage A B A C B C 3 Maximum deviation from average voltage Voltage imbalance max deviation average voltage x100 Voltage imbalance less than 2 DO NOT start chiller if voltage i
78. too much scale found Physical and chemical cleaning can be chosen according to the device you have Generally chemical cleaning is much easier to carry out Methods are as below and the services of a qualified water treatment specialist should be obtained to develop and monitor a treatment program a Cycle under normal temp A Volume of condenser volume of pipes volume of container x1 3 Note concentration of detergent 33 b Cycle under normal temp B Volume of cooling tower flume volume of condenser volume of pipes x1 10 Note concentration of detergent 10 Warning When doing cleaning with unit stops volume of cooling tower flume can be 1 2 or 1 3 of rated value but if doing cleaning with unit is runs the volume of cooling tower flume should keep rated value Midea assumes no responsibility for pressure vessel damage resulting from untreated or improperly treated water c Precautions of chemical cleaning 0 A When doing cleaning please wear rubber gloves and do not expose your skin or your clothes to the detergent In ase of touching the detergent please wash with clean water immediately A The container for detergent should be made of plastic or glass rather than lead A The used detergent should be neutralized with lime or soda before draining A Detergent is harmful to human body please keep it away from children ATurn on the unit to check the effect after cleaning work done If necessary please do cleaning again 6 3Water Tre
79. tube prior to rolling This material is intended to wick into the area of the tube that is not rolled into the tube sheet and prevent fluid from accumulating between the tube and the tube sheet New tubes must also be rolled into the center tube sheet to prevent circuit to circuit leaks TIGHTENING COOLER CONDENSER HEAD BOLTS When reassembling the evaporator head always check the condition of the O rings first The O ring should be replaced if there are visible signs of deterioration cuts or damage Apply a thin film of grease to the O ring before installation This will aid in holding the O ring in the groove while the head is installed Torque all bolts in sequence as shown in Fig 6 2 1 Torque rang N m Bolt specifications Max Min IM10 16 24 M12 45 68 M16 95 122 IM20 142 210 Fig 6 2 1 Fig 6 2 2 1 Install all bolts finger tight 2 Bolt tightening sequence is outlined in Fig 6 2 2 Follow the numbering or lettering sequence so that pressure is evenly applied to O ring 3 Apply torque in one third steps until required torque is reached Load all bolts to each one third step before proceeding to next one third step 4 No less than one hour later retighten all bolts to required torque values 5 After refrigerant is charged to system check for refrigerant leaks using halogen detector or other recommended industry practices 6 Replace evaporator insulation 6 2Inspecting Cleanin
80. ucer and display mode set a parameter the exit without saving changes y Display screen navigation UP DOWN ncrease decrease the value Es from the parameter setting mode the display switches to Enter Confirm the list of parameters and return the value OPERATION EXAMPLE Debugging Complete electrical wiring and connect the power need to debug the operation of the drive depends on the interface but basically only four parameters to set refrigerant valves pressure sensors S1 type and the type of main control After installation of the display Configurtion Confi tion mw b ahead m TS 1 shows the first parameter Network Address 3 UP DOWN button to modify the value 2 Press Enter to move to the parameter values Configurtion Network address 16 6 Repeat steps 2 3 4 5 modify refrigerant valves pressure sensors S1 and the main control parameters Configurtion End confi ation Mo EIA 7 Check the electrical wiring is correct 8 When properlv configured exit the program or select NO to return to step 2 To simplify debugging avoid failure the drive before the completion of the following configuration parameters will not start 1 network address 2 refrigerant 3 types of electronic expansion valve 4 pressure sensor Sl 5 main control type which is the use of superheat control device type Inspection after commissioning Finished debugging you shoul
81. uding gas pipes oil pipes pressure switches power cables and control cables etc All these must be reinstalled to the same place as per uninstallation procedure IMPORTANT the power cable must be connected to compressor correctly as per marks on the cables Wrong connection may cause reversal rotation and serious damages Leak check the compressor and refrigerant lines with nitrogen Repair any leaks found Remove nitrogen from system Evacuate compressor and refrigerant lines Refer to the Refrigerant Charging Adding Charge and Oil Charging Low Oil Recharging sections on pages for recharging procedures Open all shutoff valves and leak check the circuit and all fittings and joints Repair any leaks found 33 Restore main and control power to the machine Confirm all the possible alarms and reset on the screen alarm page Moisture Liguid Indicator Clear flow of liguid refrigerant indicates sufficient charge in the system Note however that bubbles in the sight glass do not necessarily indicate insufficient charge Moisture in the system is measured in parts per million ppm changes of color of indicator are Green moisture is below 80 ppm Yellow green chartreuse 80 to 225 ppm caution Yellow wet Aabove 225 ppm Change filter drier at the first sign of moisture in the system IMPORTANT Unit must in operation for at least 12 hours before moisture indicator can give an accurate reading With the unit running the in
82. ures the compressor to run normally difference protection High discharge temperature Makes the compressor run safely under permitted conditions protection Failure display Causes Solutions Compressor can not work No power Switch works over current Starting switch failure The fuse is melted Interlocking device does not work 6High low pressure switch work Switch on the power after checking Find out the cause Replace the switch or adjust the voltage Examine and replace it Replace it Check if the fan of cooling tower and all the water pump work if not make them run Adjust the pressure The unit stops Immediately after starting High low pressure switches work Insufficient cooled water in condenser Add water into it Expel the incondensable air from condenser Clean the expansion pipe or replace it if it is damaged Clean the cooled water strainer 3 Discharge pressure is too low Insufficient refrigerant High degree of superheat of expansion valve Excessive cooled water or the water temp is too low Drying strainer is blocked Check the leakage and add the refrigerant into the unit Adjust it Adjust the water volume Replace and clean the filter Over high discharge pressure 1 Excessive refrigerant Incondensable air inside Bad effect of cooling tower Water pump is damaged Pipes of condenser are dirty Hig
83. w compressor Make sure compressor is properly rigged before unbolting Move lifting apparatus into place and attach to the 2 lifting rings on the compressor When lifting the compressor it is recommended to use a steel chain or steel cable as shown in the figure below and also a safety rope can also be used provided it has loading capacity of 2000kgf Make sure that the chains cables ropes or other lifting equipment are properly positioned so as to avoid damage to compressor or its accessories Keep the compressor in horizontal position when lifting and avoid the compressor to crash or fall on the ground hit the wall or any other event that may damage it or its accessories Fig 21 Lifting the compressor with Fig 22 Lifting the compressor with safety ropes steel chain or steel cable Remove the M14 bolts securing the discharge line flange located between compressor and oil separator In the same way remove the bolts securing the suction line flange between evaporator and compressor if there is no suction service valve If there is suction service valve remove the bolts securing the suction valve to compressor Save all the hardware as it will be needed to install the replacement compressor When there s no interfere with compressor remove compressor from evaporator Compressor reinstallation Install the new compressor to the mounting bracket connect all the accessories removed before back to the new compressor incl
84. warf clogging oil filter this mav caused bearings failure The oil pressure differential switch will trip when the oil pressure differential reaches the critical point default 150kPa The compressor will automaticallv shut down to prevent the bearings from getting damaged due to the lack of lubricating oil Caution Compressor oil is pressurized Use proper safetv precautions when relieving pressure gt Additional oil charge to lubrication systems 1 If the unit shuts off repeatedly on Low Oil Level this may be an indication of inadequate oil charge It could also mean simply that there may be problems in the process of being reclaimed from the low side of the system Adjust the valves of high pressure side and evaporator side make sure oil reclaiming process effective If problem still persists additional oil charge is needed 2 Make sure that the unit is not running when adding oil as this will make the oil charging process easier Because the system is under pressure even when the unit is not running it will be necessary to use a suitable pump hand pump or electric pump to add oil to the system 3 Use a suitable pump to add appropriate Synthetic ester compressor oil absolutely no substitutes are approved to the system Make sure that the oil level safety switch is NOT tripped and allow the unit to restart and run normally Do not exceed maximum oil change See Table 33 for the quantity of oil charge Table 33 Unit Oil Quantities
85. wed If this is not the case there is a risk of material deterioration and injuries to personnel Ensure that the valves are correctly installed before operating the unit In certain cases the relief valves are installed on isolating valves These valves are factory supplied lead sealed in the open position This system permits isolation and removal of the relief valves for checking and replacing The relief valves are designed and installed to ensure protection against overpressure caused by fire Ensure good ventilation as accumulation of refrigerant in an enclosed space can displace oxygen and cause asphyxiation or explosions Inhalation of high concentrations of vapour is harmful and may cause heart irregularities unconsciousness or death Vapour is heavier than air and reduces the amount of oxygen available for breathing These products cause eye and skin irritation Decomposition products are hazardous 1 2 Maintenance safety considerations Engineers working on the electric or refrigeration components must be authorized trained and fully qualified to do so All refrigerant circuit repairs must be carried out by a trained person fully qualified to work on these units He must have been trained and be familiar with the equipment and the installation All welding operations must be carried out by qualified specialists Any manipulation opening or closing of a shut off valve must be carried out by a qualified and authorized engineer These proce
86. wer wiring is installed properly Yes No 5 Unit is properly grounded Yes No 6 Electrical circuit protection has been sized and installed properly Yes No 7 All terminals are tight Yes No 8 All plug assemblies are tight Yes No 9 All cables and thermistors have been inspected for crossed wires Yes No __ 10 All thermistors are fully inserted into wells Yes No 11 Mechanical room maintained above 50 F 10 C Yes No 12 Relief valve vent piping installed per local codes Yes No NOTE Required for unit operation where winds of 5 mph 2 2 m s or 55 greater are anticipated at outdoor ambient temperatures below 32 F 0 C Chilled Water System Check 1 All chilled water valves are open Yes No 2 All piping is connected properly Yes No 3 All air has been purged from the system Yes No 4 Chilled water pump is operating with the correct rotation Yes No 5 Chilled water pump starter interlocked with chiller Yes No 6 Inlet piping to cooler includes a water strainer Yes No 7 Water loop volume greater than 3 gal ton for air conditioning or 6 gal ton for process cooling and low ambient operation Yes No 8 Proper loop freeze protection providedto____ F CC Yes No __ Antifreeze type Concentration 90 If antifreeze solution is not utilized on 30GX machines and the minimum outdoor ambient is below 32 F 0 C then items 9 11 have to be completed to provide cooler freeze protection to 0 F Refer
87. y chilled water pump stops after 600s delay Note fault can be cleared after power re energized and it needs to be confirmed manually then when both temperature and time condition gets satisfied the chiller can restart gt Temperature sensor failure Entering chilled water temperature sensor short circuit open circuit display entering chilled water temperature fault and chiller stops according to abnormal shutdown program After the sensor reset fault on screen must be cleared manually when both temperature and time condition gets satisfied the chiller can restart Leaving chilled water temperature sensor short circuit open circuit display leaving chilled water temperature fault and chiller stops according to abnormal shutdown program After the sensor reset fault on screen must be cleared manually when both temperature and time condition gets satisfied the chiller can restart Entering cooling water temperature sensor short circuit open circuit display entering cooling water temperature fault and chiller stops according to abnormal shutdown program After the sensor reset fault on screen must be cleared manually when both temperature and time condition gets satisfied the chiller can restart Leaving cooling water temperature sensor short circuit open circuit display leaving cooling water temperature fault and chiller stops according to abnormal shutdown program After the sensor reset fault on screen must be cleared manually when both tem

Water Cooled Screw Chiller Technical Service Manual

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