York SUNLINE MagnaDRY DR180 Installation Manual

Also see for SUNLINE MagnaDRY DR 180: Submittal data sheet Installation manual

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York SUNLINE MagnaDRY DR180 Installation Manual Manual pdf 59 page image

127915-YIM-A-0405Unitary Products Group 59ELECTRIC HEATING SEQUENCE OF OPERATIONSThe following sequence describes the operation of theelectric heat section.Single-stage heating (applies only to 18 KW heater, allother heaters MUST use a two-stage thermostat):a. Upon a call for heat by the thermostat, the heatercontactor (6M) will be energized. After completingthe specified fan on delay for heating, the UCB willenergize the blower motor.b. The thermostat will cycle the electric heat to satisfythe heating requirements of the conditioned space.Two-stage heating (applies to all heaters except 18KW):a. Upon a call for first-stage heat by the thermostat, theheater contactor (6M) (6M & 7M on 72 KW, 240V)will be energized. After completing the specified fanon delay for heating, the UCB will energize theblower motor.If the second stage of heat is required, heater con-tactor (7M) will be energized. Note that on the 54KW, 240V heater, heater contactors (7M & 8M) willbe energized and on the 72 KW, 240V heater,heater contactors (8M & 9M) will be energized. Aftercompleting the specified fan on delay for heating,the UCB will energize the blower motor.b. The thermostat will cycle the electric heat to satisfythe heating requirements of the conditioned space.FIGURE 22 - SYSTEM PIPING SCHEMATICC1TXVFSLPSHPSCondenserFanAir Flow Air FlowAir FlowHot Gas Re-HeatSolenoid ValveIndoor BlowerBleed Line to clearthe Hot Gas Coilwhen it is not in useEvaporatorCoil Hot GasCoilCompressorPiping TPiping TCheckValveCondenserCoilCheckValveSol 2Suction linebleedOpen inReheatOpen inCoolingHPS(Sol 3)Sol 1Refrigerant flow in reheat modeRefrigerant flow in cooling modeAccumulator