York SUNLINE DCG Series Installation Manual

Contents

York SUNLINE DCG Series Installation Manual Manual pdf 40 page image

290699-YIM-B-060740 Unitary Products GroupCOOLING SEQUENCE OF OPERATIONCONTINUOUS BLOWERBy setting the room thermostat fan switch to “ON,” thesupply air blower will operate continuously.INTERMITTENT BLOWERWith the room thermostat fan switch set to “AUTO” andthe system switch set to either the “AUTO” or “HEAT”settings, the blower is energized whenever a cooling orheating operation is requested. The blower is ener-gized after any specified delay associated with theoperation.When energized, the indoor blower has a minimum runtime of 30 seconds. Additionally, the indoor blower hasa delay of 10 seconds between operations.NO OUTDOOR AIR OPTIONSWhen the thermostat calls for cooling, the low-voltagecontrol circuit from “R” to “Y1” and “G” is completed.The compressor and condenser fan motor are ener-gized. After completing the specified fan on delay forcooling, the UCB will energize the blower motor.Once the thermostat has been satisfied, it will de-ener-gize Y1. If the compressor has satisfied its minimumrun time, the compressor and condenser fan de-ener-gize. Otherwise, the unit operates the cooling systemuntil the minimum run time for the compressor hasbeen completed. After the compressor de-energizes,the blower is stopped following the elapse of the fan offdelay for cooling.To be available, a compressor must not be locked-outdue to a high or low-pressure switch or freezestat tripand the anti-short cycle delay (ASCD) must haveelapsed.ECONOMIZER WITH SINGLE ENTHALPY SENSORWhen the room thermostat calls for cooling, the lowvoltage control circuit from “R” to “G” and “Y1” is com-pleted. The UCB energizes the blower motor (if the fanswitch on the room thermostat is set in the “AUTO”position) and drives the economizer dampers from fullyclosed to their minimum position. If the enthalpy of theoutdoor air is below the setpoint of the enthalpy con-troller (previously determined), “Y1” energizes theeconomizer. The dampers will modulate to maintain aconstant supply air temperature as monitored by thedischarge air sensor. If the outdoor air enthalpy isabove the setpoint, “Y1” energizes the compressor andcondenser fan motor only.Once the thermostat has been satisfied, it will de-ener-gize “Y1”. If the compressor has satisfied its minimumrun time, the compressor and condenser fan are de-energized. Otherwise, the unit operates the coolingsystem until the minimum run times for the compressorhas been completed. After the compressor de-ener-gizes, the blower is stopped following the elapse of thefan off delay for cooling, and the economizer dampergoes to the closed position. If the unit is in continuesfan operation the economizer damper goes to the min.position.ECONOMIZER WITH DUAL ENTHALPY SENSORSThe operation with the dual enthalpy sensors is identi-cal to the single sensor except that a second enthalpysensor is mounted in the return air. This return air sen-sor allows the economizer to choose between outdoorair and return air, whichever has the lowest enthalpyvalue, to provide maximum operating efficiency.ECONOMIZER (SINGLE OR DUAL) WITH POWEREXHAUSTThis system operates as specified above with oneaddition. The power exhaust motor is energized 45seconds after the actuator position exceeds theexhaust fan setpoint on the economizer control. Whenthe power exhaust is operating, the second stage ofmechanical cooling will not operate. As always, the “R”to “G” connection provides minimum position but doesnot provide power exhaust operation.MOTORIZED OUTDOOR AIR DAMPERSThis system operation is the same as the units with nooutdoor air options with one exception. When the “R” to“G” circuit is complete, the motorized damper drivesopen to a position set by the thumbnail on the dampermotor. When the “R” to “G” circuit is opened, thedamper spring returns fully closed.COOLING OPERATION ERRORSEach cooling system is monitored for operation outsideof the intended parameters. Errors are handled asdescribed below. All system errors override minimumrun times for compressors.