Carrier GT-PX Split Series Installation, Operation & Maintenance Instructions Manual

R e s i d e n t i a l S p l i t - 6 0 H z R 2 2 & R 4 1 0 AR e v. : 5 J u n e , 2 0 0 830 W a t e r- S o u r c e H e a t i n g a n d C o o l i n g S y s t e m sElectrical - Low Voltage WiringELECTRICAL - LOW VOLTAGE WIRINGThermostat ConnectionsThe thermostat should be wired directly to the CXM board.Figures 22a through 22c show low voltage wiring. Note thatthe air handler or furnace transformer will be used to powerthe CXM board in the compressor section. See “Electrical –Thermostat” for specific terminal connections.Figure 22a: 50YDS Low Voltage Field WiringFigure 22b: GT-GS Low Voltage Field WiringFigure 22c: GT-S Low Voltage Field WiringCapacitorCXM ControlCirc BrkrContactor -CCBRLow VoltageConnectorHWG PB2Loop PB1L2 L1GrndFCRCRRThermostat ConnectionSee Thermostat sectionfor Wiring DetailsCRCGrndL2 L1T2 T1CCCXM ControlLow VoltageConnectorLow Water Temperature Cutout SelectionThe CXM control allows the field selection of low water (orwater-antifreeze solution) temperature limit by clipping jumperJW3, which changes the sensing temperature associated withthermistor FP1. Note that the FP1 thermistor is located onthe refrigerant line between the coaxial heat exchanger andexpansion device (TXV). Therefore, FP1 is sensing refrigeranttemperature, not water temperature, which is a better indicationof how water flow rate/temperature is affecting the refrigerationcircuit.The factory setting for FP1 is for systems using water (30°F[-1.1°C] refrigerant temperature). In low water temperature(extended range) applications with antifreeze (most groundloops), jumper JW3 should be clipped as shown in Figure23 to change the setting to 10°F [-12.2°C] refrigeranttemperature, a more suitable temperature when usingan antifreeze solution. All residential units include water/refrigerant circuit insulation to prevent internal condensation,which is required when operating with entering watertemperatures below 59°F [15°C].Low voltagefield wiring