Carrier PERFORMANCE 50VT-A Installation Instructions Manual

Also see for COMFORT 50VT-A: Owner's information manual Owner's information manual Installation instructions

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Carrier PERFORMANCE 50VT-A Installation Instructions Manual Manual pdf 9 page image

9POWERSUPPLYFIELD-SUPPLIEDFUSED DISCONNECTHIGH VOLTAGEPOWER LEADS(SEE UNIT WIRINGLABEL)EQUIP GRCONTROL BOXLOW-VOLTAGEPOWER LEADS(SEE UNITWIRING LABEL)W1YGRCWHT(W1)YEL(Y)GRN(G)RED(R)BRN(C)THERMOSTAT(TYPICAL)ORN(O)3-PHASE SHOWN1-PHASE USESTWO POWERLEADSW2VIO (W2)OSPLICE BOXDHBLU(DH)3-PhaseOnlyGRA(Y2)A09071Fig. 10 -- High-- and Control--Voltage ConnectionsSingle phase units:1. Run the high--voltage (L1, L2) and ground lead into thecontrol box.2. Connect ground lead to chassis ground connection.3. Locate the black and yellow wires connected to the line sideof the contactor.4. Connect field L1 to black wire on connection 11 of thecompressor contactor.5. Connect field wire L2 to yellow wire on connection 23 ofthe compressor contactor.Three--phase units:1. Run the high--voltage (L1, L2, L3) and ground lead into thecontrol box.2. Connect ground lead to chassis ground connection.3. Locate the black and yellow wires connected to the line sideof the contactor.4. Connect field L1 to black wire on connection 11 of thecompressor contactor.5. Connect field wire L3 to yellow wire on connection 13 ofthe compressor contactor.6. Connect field wire L2 to blue wire from compressor.Special Procedures for 208--V OperationELECTRICAL SHOCK HAZARDFailure to follow this warning could result in personalinjury or death.Before installing or servicing system, always turn off mainpower to system. Tag the disconnect switch with a suitablewarning label. With disconnect switch open, move blackwire from transformer (3/16 in.) terminal marked 230 toterminal marked 208. This retaps transformer to primaryvoltage of 208 vac.! WARNINGControl Voltage ConnectionsNOTE: Do not use any type of power--stealing thermostat. Unitcontrol problems may result.Use no. 18 American Wire Gage (AWG) color--coded, insulated(35°C minimum) wires to make the control voltage connectionsbetween the thermostat and the unit. If the thermostat is locatedmore than 100 ft (30.5 m) from the unit (as measured along thecontrol voltage wires), use no. 16 AWG color--coded, insulated(35° C minimum) wires.Standard ConnectionsLocate the eight (nine on 3--phase) low voltage thermostat leads in24 volt splice box. See Fig. 10 for connection diagram. Run thelow--voltage leads from the thermostat, through the control wiringinlet hole grommet (Fig. 2 and 3), and into the low--voltage splicebox. Provide a drip loop before running wires through panel.Secure and strain relief all wires so that they do not interfere withoperation of unit. A gray wire is standard on 3--phase units forconnection to an economizer.If an accessory electric heater is installed, low voltage leads fromheater must be connected to factory supplied control leads fromIndoor Fan Board P4 connector.NOTE: If the unit 24V wires do not have a matching receptacle,cut the 24V wires from the electric heater plug, strip the ends, andwire nut together to match the schematic connections. If the electricheater 24V wires do not have a matching plug, cut the 24V wiresfrom the unit receptacle, strip the ends, and wire nut together tomatch the schematic connections.Factory wires are provided for electric heat staging W1 and W2(W2 and W3 on IFB). If room thermostat has only one stage ofsupplemental heat, connect white and violet wires shown in Fig. 10to second stage heat field wire.Some electric heaters have four control wires (plus common wire).Consult unit wiring diagram and electric heater wiring diagram foradditional details.Transformer ProtectionThe transformer is of the energy--limiting type. It is set to withstanda 30--second overload or shorted secondary condition. If anoverload or short is present, correct overload condition and checkfor blown fuse on Interface Fan Board. Replace fuse as requiredwith correct size and rating.Accessory Electric Heaters InstallationElectric heaters may be installed with the 50VT--A units perinstructions supplied with electric heater package. See unit ratingplate for factory--approved electric heater kits.Sequence of Operationa. CONTINUOUS FAN(1.) Thermostat closes circuit R to G energizing theblower motor for continuous fan.b. COOLING MODE(1.) If indoor temperature is above temperature setpoint, thermostat closes circuits R to G, R to Y andR to O--The unit delivers cooling airflow.c. ELECTRIC HEATING MODE(1.) Thermostat closes circuit R to W/W1, or W2 and Rto G. There are no on or off delays.d. HEAT PUMP HEATING MODE(1.) Thermostat closes circuits R to G and R to Y. Thecompressor, indoor and outdoor fans are energized.e. HEAT PUMP HEATING WITH AUXILIARYELECTRIC HEAT(1.) Thermostat closes circuits R to G, R to Y and R toW/W1 or W2. The compressor, indoor and outdoorfans are energized, as well as the electric heatrelays.f. DEFROST MODEThe defrost mode is automatically energized by thedefrost board during heating mode. The defrost boardenergizes “O” (reversing valve) and “W2” (electricheat). It also de--energizes the outdoor fan. When defrostis complete, unit will return to heating mode. If roomthermostat is satisfied during defrost, unit will shutdown and restart in defrost on next call for heat.50VT-- A