York YMC2 A, Operation And Maintenance

Page 1: ...8 1415 in R 134a YMC2 Model A with OptiView Control Center Centrifugal Liquid Chillers Operations and Maintenance Supersedes 160 78 O1 820 Form 160 78 O1 521 Issue Date May 19 2021 ...

Page 2: ...question Safety symbols The following symbols are used in this document to alert the reader to specific situations Indicates a possible hazardous situation which will result in death or serious injury if proper care is not taken Indicates a potentially hazardous situa tion which will result in possible injuries or damage to equipment if proper care is not taken Identifies a hazard which could lead...

Page 3: ...nections 160 78 PW1 YMC2 Unit Wiring and Field Control Modifications 160 78 PW2 YMC2 Unit Renewal Parts 160 78 RP1 YMC2 OptiViewTM Contol Center Operation Manual 160 78 O2 OptiSpeedTM VSD Model HYP744 Renewal Parts 160 78 RP3 Affected pages Description 24 Replaced maintenance requirements table with maintenance inspections section Revision notes Revisions made to this document are indicated in the...

Page 4: ...3 5 1 in Code 4 Heat exchanger mod level Nominal inside diameter inches Nominal length feet Marketing tube number E A 25 14 271 B R 1 1 F C R Compressor nomenclature Gas path revision level Impeller design revision level Motor Motor design level Impeller tip diameter mm Rotation F Forward R Reverse M1 B 197 F A A System nomenclature YORK Centrifugal chiller Magnetic bearing Mod level S Single stag...

Page 5: ...erature control 13 Operating logs 13 Operating inspections 14 Daily 14 Weekly 15 Monthly 15 Semi annually or more often as required 15 Annually more often if necessary 15 Need for maintenance or service 15 Stopping the system 15 Prolonged shutdown 15 SECTION 3 MAINTENANCE 17 Renewal parts 17 Checking system for leaks 17 Leak testing during operation 17 Conducting R 22 pressure test 17 Vacuum testi...

Page 6: ... more often as required 24 Annually more often if necessary 24 SECTION 4 TROUBLESHOOTING 25 List of figures List of tables FIGURE 1 YMC2 chiller components 7 FIGURE 2 Compressor prerotation vanes 9 FIGURE 3 Refrigerant flow through chiller 11 FIGURE 4 Liquid chiller log sheets 14 FIGURE 5 Evacuation of chiller 17 FIGURE 6 Saturation curve 19 TABLE 1 System pressures 18 TABLE 2 Refrigerant charge 2...

Page 7: ...es Gas path revisions B has fixed inlet vanes Motor The compressor motor is a hermetic permanent magnet high speed design with magnetic bearings The com pressor impeller is overhung from the end of the motor shaft and has no bearings of it s own The motor includes angular contact ball bearings only for control of the rotor during shutdown after rotation is stopped or during shutdown due to loss of...

Page 8: ...evel 0 empty 100 full Under program control the Microboard modulates a variable orifice to control the condenser refrigerant level to a programmed setpoint Other setpoints affect the control sensitivity and response These setpoints must be entered at chiller commissioning by a qualified service technician Only a qualified service technician may modify these settings While the chiller is shut down ...

Page 9: ...ts or other air conditioning terminal units where it flows through finned coils absorbing heat from the air The warmed liquid is then returned to the chiller to complete the chilled liquid circuit The refrigerant vapor which is produced by the boil ing action in the evaporator flows to the compressor where the rotating impeller increases its pressure and temperature and discharges it into the cond...

Page 10: ...ressor models with gas path revision level B do not have operating prerotation vanes but use the VGD also as a capacity control device instead A final optional means to reduce capacity called hot gas bypass HGBP is available regardless of compres sor model When selected for an application HGBP is used to re circulate some refrigerant through the com pressor without using it for cooling the chilled...

Page 11: ...ow through chiller COMPRESSOR EVAPORATOR DISCHARGE PRE ROTATION VANES M1B 197FAA and M1B 205FAA SUCTION BAFFLE SUB COOLER CONDENSER SUCTION LIQUID COOLING FOR MOTOR STATOR ISOLATION VALVE ROTOR COOLING GAS VENT M1B 197FAA and M1B 205FAA ISOLATION VALVE DISCHARGE CHECK VALVE LIQUID LEVEL VALVE HOT GAS BYPASS VALVE ...

Page 12: ...JOHNSON CONTROLS 12 Form 160 78 O1 Issue date 05 19 2021 THIS PAGE INTENTIONALLY LEFT BLANK ...

Page 13: ... as factory supplied on a chiller order by special quotation Chiller operation The chiller will vary capacity to maintain the leaving chilled liquid temperature setpoint by a specific se quencing of optional hot gas bypass pre rotation vanes or variable geometry diffuser and compressor speed Throughout capacity control the compressor speed is maintained above the minimum required for the pre vaili...

Page 14: ... 4 Check the condenser saturation temperature on the SYSTEM Screen This temperature is based on the condenser pressure that is detected by the condenser transducer 5 Check the compressor discharge temperature on the SYSTEM Screen During normal operation discharge temperature should not exceed 220 F 104 C 6 Check the compressor motor current on the SYS TEM Screen Figure 4 Liquid chiller log sheets ...

Page 15: ... chiller complete the following steps 1 Push the soft shutdown key on the Home screen of the OptiViewTM panel The compressor will stop automatically In the event of an unusual cir cumstance requiring immediate stoppage a safety stop switch is located on the side of the control panel Normal stop eases the driveline to stop and should always be used instead of the safety stop during regular operatio...

Page 16: ...JOHNSON CONTROLS 16 Form 160 78 O1 Issue date 05 19 2021 THIS PAGE INTENTIONALLY LEFT BLANK ...

Page 17: ...ide torch or electronic leak detector can be used to de tect any leaks too small to be found by the soap test To test with R 22 complete the following steps 1 With no pressure in the system charge R 22 gas into the system through the charging valve to a pressure of 2 psig 14 kPa 2 Build up the system pressure with dry nitrogen to approximately 75 psig to 100 psig 517 kPa to 690 kPa To be sure that...

Page 18: ... mm Hg is reached See Table 1 for corresponding pressure values 4 To improve evacuation circulate hot water not to exceed 125 F 51 7ºC through the evapora tor and condenser tubes to thoroughly dehydrate Table 1 System pressures Gauge Absolute Boiling temperatures of water F Inches of mercury Hg below one standard atmosphere psia Millimeters of mercury Hg Microns 0 in 14 6960 760 00 760 000 212 10 ...

Page 19: ...od of de hydration consists of a wet bulb indicator or vacuum gauge a chart showing the relation between dew point temperature and pressure in inches of mercury in a vacuum see Table 1 and a vacuum pump capable of pumping a suitable vacuum on the system Operation A refrigerant system can be dehydrated using this method because the water present in the system reacts to changes in a similar way that...

Page 20: ...m pressure until the system pressure is raised above the point correspond ing to the freezing point of the evaporator liquid For water the pressure corresponding to the freezing point is 29 psig 200 kPa for R 134a at sea level While charging every precaution must be taken to pre vent moisture laden air from entering the system Make up a suitable charging connection from new copper tubing to fit be...

Page 21: ...easure against scale and corrosion and to prolong the life of evaporator and condenser tubes a chemical analysis of the water should be made preferably before the system is installed A reliable wa ter treatment company can be consulted to determine whether water treatment is necessary and if so to fur nish the proper treatment for the particular water con dition Cleaning evaporator and condenser t...

Page 22: ...anches in principal cities is one of the most reli able of these companies Testing for evaporator and condenser tube leaks Evaporator and condenser tube leaks in R 134a sys tems may result in refrigerant leaking into the water circuit or water leaking into the shell depending on the pressure levels If refrigerant is leaking into the water it can be detected at the liquid head vents after a period ...

Page 23: ...the tube walls Place a fan at the end of the evaporator opposite the detector This ensures that any leakage wi travel through the tube to the detector 5 Mark any leaking tubes for later identification 6 If any of the tube sheet joints are leaking the leak should be indicated by the detector If a tube sheet leak is suspected its exact location may be found by using a soap solution A continuous buil...

Page 24: ...ed 220 F 104 C Check the compressor motor current on the Compressor screen Weekly Check the refrigerant charge See Checking the refrigerant charge during unit shutdown Check for any signs of dirty or fouled condenser tubes The temperature difference between the water leaving the condenser and the saturated condensing temperature must not exceed the dif ference recorded for a new unit by more than ...

Page 25: ... 2 Symptom abnormally low suction pressure Temperature difference between leaving chilled water and refrigerant in the evaporator greater than normal with normal discharge temperature Insufficient charge of refrigerant Check for leaks and charge refrigerant into system Variable orifice problem Remove obstruction Temperature difference between leaving chilled water and refrigerant in the evaporator...

Page 26: ...JOHNSON CONTROLS 26 Form 160 78 O1 Issue date 05 19 2021 THIS PAGE INTENTIONALLY LEFT BLANK ...

Page 27: ...Celsius multiply by 5 9 or 0 5556 Example 10 0 F range x 0 5556 5 6 C range Table 4 SI metric conversion Measurement Multiply English unit By factor To obtain metric unit Capacity Tons refrigerant effect ton 3 516 Kilowatts kW Power Horsepower 0 7457 Kilowatts kW Flow rate Gallons minute gpm 0 0631 Liters second L s Length Feet ft 0 3048 Meters m Inches in 25 4 Millimeters mm Weight Pounds lb 0 45...

Page 28: ...om Pennsylvania USA 17349 1 800 524 1330 Subject to change without notice Printed in USA Copyright by Johnson Controls 2021 www johnsoncontrols com ALL RIGHTS RESERVED Form 160 78 O1 521 Issue Date May 19 2021 Supersedes 160 78 O1 820 ...