Sterling 30RA010-055 manual Cooler Freeze-Upprotection

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COOLER FREEZE-UP PROTECTION

COOLER FREEZE-UP PROTECTION

On medium temperature brine units, the brine must be properly mixed to prevent freezing at a temperature of at least 15 F (8.3 C) below the leaving-fluid temperature set point. Failure to provide the proper brine mixture is consid- ered abuse and may void the Sterling warranty.

The Main Base Board (MBB) monitors leaving fluid tem- perature at all times. The MBB will rapidly remove stages of capacity as necessary to prevent freezing conditions due to the rapid loss of load or low cooler fluid flow.

When the cooler is exposed to lower ambient temperatures (34 F [1° C] or below), freeze-up protection is required using inhibited ethylene glycol.

HEATER CABLE — Optional factory-installed cooler and/or hydronic package heaters are cycled based on the input from the outside-air temperature sensor. These heaters, when in- stalled, are designed to protect the cooler and/or hydronic pack- age from freezing down to –20 F (–29 C). Power for these heat- ers is supplied from the main unit power.

The input from the low pressure transducer provides a back- up cooler freeze protection package. The MBB shuts down the unit when a low pressure condition exists that could cause the cooler to freeze up.

Do not disconnect main unit power when servicing com- pressor(s) if ambient temperature is below 40 F (4.4 C). Each compressor manual starter has a lockout feature. Depress the Stop Button and pull the lockout tab from the start button. Secure lock in place. If power to the unit must be off for a prolonged period, drain the cooler, hydronic package (if installed) and internal piping. Add glycol according to WINTER SHUTDOWN Step 2 below.

WINTER SHUTDOWN — At the end of the cooling season:

1.Drain the water/brine from the cooler, hydronic package (if installed) and internal piping.

2.Fill the package with at least 2 gallons (7.6 L) of ethylene glycol or other suitable uninhibited antifreeze solution to prevent any residual water in the cooler and hydronic package/piping from freezing.

3.At the beginning of the next cooling season, refill the cooler and add the recommended inhibitor.

Thermistors — Electronic control uses up to five 5 kΩ thermistors to sense temperatures used to control operation of the chiller. Thermistors T1, T2 and T9 are identical in their temperature and voltage drop performance. Accessory return gas thermistors are also 5 kΩ thermistors used to troubleshoot TXV superheat settings. Thermistor T10 has a 10 kΩ input channel and has a different set of temperature vs. resistance and voltage drop performance. Resistance at various temperatures are listed in Tables 33-36.

NOTE: For dual chiller operation, the control automatically configures the T10 input channel to be a 5 kΩ channel. A HH79NZ014 or HH79NZ029 thermistor should be used for dual chiller configurations.

Thermistor pin connection points are shown in Table 2. Ther- mistor T1 is located in a well at the bottom of the brazed plate heat exchanger for sizes 010-030 and in the leaving fluid pip- ing for sizes 032-055.

Thermistor T2 is located in a well at the top of the brazed plate heat exchanger for sizes 010-030 and in the entering fluid piping for sizes 032-055. Thermistor T9 is factory installed in

the compressor section behind a panel with a vent plug so that outside air flows across the sensor tip.

REPLACING THERMISTORS T1 and T2 — Add a small amount of thermal conductive grease to the thermistor well and end of probe. Thermistors are friction-fit thermistors, which must be slipped into receivers in the cooler (010-030) or fluid piping (032-055). For sizes 032-055, tighten the retaining nut ¼ turn past finger tight. See Fig. 35.

THERMISTOR/TEMPERATURE SENSOR CHECK — A high quality digital volt-ohmmeter is required to perform this check.

1.Connect the digital voltmeter across the appropriate themistor terminals at the J8 terminal strip on the Main Base Board (see Fig. 36).

2.Using the voltage reading obtained, read the sensor tem- perature from Tables 33-36.

3.To check thermistor accuracy, measure temperature at probe location with an accurate thermocouple-type tem- perature measuring instrument. Insulate thermocouple to avoid ambient temperatures from influencing reading. Temperature measured by thermocouple and temperature determined from thermistor voltage reading should be close, ± 5° F (3° C) if care was taken in applying thermo- couple and taking readings.

If a more accurate check is required, unit must be shut down and thermistor removed and checked at a known temperature (freezing point or boiling point of water) using either voltage drop measured across thermistor at the J8 terminal, by deter- mining the resistance with chiller shut down and thermistor disconnected from J8. Compare the values determined with the value read by the control in the Temperatures mode using the Scrolling Marquee display.

Pressure Transducers — Suction and discharge pres- sure transducers are installed on each circuit. No pressure transducer calibration is required. The transducers operate on a 5 vdc supply, which is generated by the Main Base Board (MBB). See Fig. 36 for transducer connections to the J8 con- nector on the MBB.

TROUBLESHOOTING — If a transducer is suspected of be- ing faulty, first check the supply voltage to transducer. Supply voltage should be 5 vdc ± 0.2 v. If supply voltage is correct, compare pressure reading displayed on the Scrolling Marquee display module against pressure shown on a calibrated pressure gauge. Suction pressure should be within ± 2 psig. Discharge pressure should be within ± 5 psig. If the two readings are not reasonably close, replace the pressure transducer.

Flow Sensor — A flow switch is factory installed in the leaving fluid piping of all models. If the unit is equipped with an optional hydronic system, the flow switch is inside the pump cabinet. If nuisance trips of the sensor are occurring, fol- low the steps below to correct the situation:

1.Check to confirm that the factory installed strainer is clean. Use the blow-down valve provided or remove the screen and clean it. For the case of VFD controlled pumps, ensure that the minimum speed setting has not been changed.

2.Measure the pressure drop across the cooler or cooler/ pump system and compare this to the system requirements.

3.Verify that cable connections at the switch and at the ter- minal block are secure.

4.For factory-installed hydronic systems, verify that:

•All air has been purged from the system

•Circuit setter balance valve has been correctly set

5.Pump impeller has been improperly trimmed and is not providing sufficient flow.

6.Wrong pump motor rotation. Pump must rotate clockwise when viewed from motor end of pump.

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Contents SAFETY CONSIDERATIONS GENERAL CONTENTSTable 1 — Unit Sizes MAJOR SYSTEM COMPONENTSControl Module Communication Sterlco Comfort Network SCN Interface —Table 4 - Output Relays Table 3 — Status SwitchesTable 5 - SCN Communication Bus Wiring Table 2 — Thermistor DesignationsLEGEND FOR FIG. Page Page 30RA010-018AQUA SNAP Fig. 3 — Wiring Schematic 30RA010-018AQUA-SNAPLOW VOLTAGE CONTROL SCHEMATIC Fig. 3 - Wiring Schematic 30RA010-018contSEE NOTE SEE NOTE 30RA022-030AQUA SNAP Fig. 4 - Wiring Schematic 30RA022-030AQUA-SNAPLOW VOLTAGE CONTROL SCHEMATIC Fig. 4 - Wiring Schematic 30RA022-030cont30RA032-040AQUA SNAP Fig. 5 — Wiring Schematic 30RA032-040AQUA-SNAPLOW VOLTAGE CONTROL SCHEMATIC Fig. 5 — Wiring Schematic 30RA032-040cont30RA042-055AQUA SNAP Fig. 6 — Wiring Schematic 30RA042-055AQUA-SNAPLOW VOLTAGE CONTROL SCHEMATIC Fig. 6 — Wiring Schematic 30RA042-055contMODE Fig. 7 — Main Base BoardESCAPEENTER REMOTE CONTACT SW1 OFF ENABLE OFF SW2 ONFig. 9 — Typical Space Temperature Sensor Wiring CEPL130351 Fig. 11 - Energy Management Module100/100 Fig. 12 — Deadband Multiplier Fig. 13 — Operating Envelope for R-22Maneurop CompressorFig. 14 — 30RA Condenser Fan Sequence Cooling Set Point Select Fig. 16 — Scrolling Marquee Display Service Test See Table 11 — Both main powerand control circuit power must be on Table 8 — Control Methods and Cooling Set PointsOptional Factory-InstalledHydronic Package — •Cooler Pump Control CPC Configuration, OPT1 ON Table 9 — Marquee Display Menu Structure Fig. 17 — Dual Chiller Thermistor LocationTable 10 — Run Status Mode and Sub-ModeDirectory SUB-MODE Table 12 - Temperature Mode and Sub-ModeDirectory Table 13 — Pressure Mode and Sub-ModeDirectory Table 14 — Set Point and Sub-ModeDirectoryTable 15 — Inputs Mode and Sub-ModeDirectory DISPLAY Table 16 — Outputs Mode and Sub-ModeDirectorySUB-MODE KEYPADDISPLAY SUB-MODEKEYPAD ITEMDISPLAY SUB-MODEKEYPAD ITEMTable 18 — Time Clock Mode and Sub-ModeDirectory PER.3 SUB-MODE Table 19 — Operating Mode and Sub-ModeDirectory Table 20 — Alarms Mode and Sub-ModeDirectoryDISPLAY SUB-MODEITEM KEYPAD ENTRYRSET DISP Table 23 — Operating Modes Table 25A — 4-20mA Reset Table 24 — Example of Reading and Clearing AlarmsTable 26B — Configuring Return Temperature Reset Fig. 20 — Space Temperature Reset Fig. 18 — Standard Chilled FluidTemperature Control — No Reset Fig. 19 — Outdoor-AirTemperature ResetFig. 21B — Cooling Set Point 4 to 20 mA Fig. 21A — 4- to 20-mADemand LimitingTable 27 — Configuring Demand Limit TROUBLESHOOTINGTable 28 — Troubleshooting Recommended that system be filled with an approand fluid tubing FU — Fuse GND — Ground Fig. 22 — Component Arrangement — 30RA010-030FU — Fuse GND — Ground Fig. 23 — Component Arrangement — 30RA032-040FU — Fuse GND — Ground Fig. 24 — Component Arrangement — 30RA042-055NOTES LEGEND Table 29 — Alarm and Alert Codes Table 29 - Alarm and Alert Codes cont ALARM Table 29 — Alarm and Alert Codes contALARM Table 29 — Alarm and Alert Codes contALARM Table 29 — Alarm and Alert Codes contElectronic Components SERVICECompressor Replacement Refer to Fig Table 30 - Unit Torque SpecificationFig. 30 — Compressor Location — 30RA032-055 Fig. 28 — Compressor WiringFig. 27 — Typical Compressor Mounting — All Sizes Fig. 29 — Compressor Location — 30RA010-030Table 31 - Oil Charge Condenser Section and CoilsFig. 33 — Condenser-FanPosition Standard Fan Fig. 31 — 30RA Access PanelsCheck Refrigerant Feed Components Fig. 32 — Condenser-FanMountingCheck Unit Safeties Table 32 — Factory Settings, High-PressureSwitch Fixed Compressor and Unit Protective DevicesCOOLER FREEZE-UPPROTECTION TEMP TEMP For Thermistor T10 For Thermistor T10 Main Base Board, J8 Connector Fig. 35 — Fluid-SideTemperature Sensors T1 and T2Fig. 36 — Thermistor Connections to PROGRAMMING Mode Table 37 - Fault Codes •P50: FAULT HISTORY — Last 8 faults•P51: SOFTWARE version PARAMETERS Table 39 — Replacement Modules System Check MAINTENANCEMinimum Loop Volume PRE-START-UPOperating Limitations OPERATION SEQUENCE Table 41 — Temperature Limits forStandard 30RA Units CIRCA_AN Circuit A Analog Parameters APPENDIX ASCN Tables A_UNIT General Unit Parameters CIRCADIO Circuit A Discrete Inputs/OutputsCIRCBDIO Circuit B Discrete Inputs/Outputs CIRCB_AN Circuit B Analog ParametersOPTIONS Unit Parameters BRODEFS Broadcast POC Definition Table ALARMDEF Alarm Definition TableDISPLAY Marquee Display SETUP DUALCHIL Dual Chiller Configuration SettingsOPTIONS2 Options 2 Configuration OPTIONS1 Options 1 ConfigurationSCHEDOVR Timed Override Setup RESETCON Temperature Reset and Demand LimitSETPOINT ALARMS: Maintenance Display UNITMAINTENANCE DUALCHIL: Maintenance Display CURRMODS: Maintenance DisplayLOADFACT: Maintenance Display LEARNFNS Maintenance DisplayPM-COIL:Maintenance Display PM-PUMP:Maintenance DisplayPM-STRN Maintenance Display RUNTEST: Maintenance Display STRTHOUR Maintenance Display TESTMODE: Maintenance DisplayVERSIONS: Maintenance Display WSMDEFME: Maintenance Display FACTORY SETTINGS FOR COMPRESSOR, FAN, PUMP APPENDIX BAND MANUAL STARTERS FACTORY SETTINGS FOR COMPRESSOR, FAN, PUMP AND MANUAL STARTERS contDataPort, DataLink, BAClink Object Definition APPENDIX CSETPOINT OPTIONSDesign Information START-UPCHECKLIST FOR 30RA LIQUID CHILLERRemove and use for Job File I.Project Information II. Preliminary Equipment CheckStart and Operate Machine. Complete the Following III. Unit Start-UpCL-3 Record Software Versions MODE — RUN STATUS COMMENTSCL-4 UNIT Configuration Settings OPTIONS1 Options ConfigurationIII.Unit Start-Upcont CL-6 OPTIONS2 Options ConfigurationRSET Reset Configuration Settings III.Unit Start-UpcontCL-7 SLCT Setpoint and Ramp Load ConfigurationIII.Unit Start-Upcont SETPOINTIII.Unit Start-Upcont Service Test Mode and Sub-ModeDirectory
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