York SUNLINE 2000 Installation Manual

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175245-YIM-C-100826 Johnson Controls Unitary ProductsOPERATIONSEQUENCE OF OPERATIONS OVERVIEWFor these units, the thermostat makes a circuitbetween "R" and "Y1" for the first stage of cooling.The call is passed to the Unit Control Board (UCB),which then determines whether the requested opera-tion is available and, if so, which components to ener-gize.For heating, the thermostat makes a circuit between“R” and “W1” for the first stage of heating. The UCBenergizes all compressors and their condenser fans.The “W1” call also energizes a separate relay (RW1),de-energizing the reversing valves allowing the unit torun in the heating mode. A time / temperature controloperates the defrost cycle.The thermostat makes a circuit between “R” and “W2”for the second stage of heating. The UCB passes the“W2” signal on energizing a relay (RW2), which ener-gizes the electric heaters if available.In both cases, when the "W1" call is sensed, the indoorair blower is energized following a specified heatingdelay.If at any time a call for both heating and cooling arepresent, the heating operation will be performed. Ifoperating, the cooling system is halted as with a com-pletion of a call for cooling. Heating always takes prior-ity.COOLING 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 the first stage of cooling,the low-voltage control circuit from "R" to "Y1" and "G"is completed. For first stage cooling, compressor #1and condenser fan motor #1 are energized. After com-pleting the specified fan on delay for cooling, the UCBwill energize the blower motor.When the thermostat calls for the second stage of cool-ing, the low-voltage control circuit from "R" to "Y2" iscompleted. Compressor #2 and condenser fan motor#2, are energized, provided it has not been locked-out.If there is an initial call for both stages of cooling, theUCB will delay energizing compressor #2, by 30 sec-onds in order to avoid a power in-rush.Once the thermostat has been satisfied, it will de-ener-gize Y1 and Y2. If the compressors have satisfied theirminimum run times, the compressors and condenserfans are de-energized. Otherwise, the unit operateseach cooling system until the minimum run times forthe compressors have been completed. Upon the finalcompressor de-energizing, the blower is stopped fol-lowing the elapse of the fan off delay 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 SENSOR -When the room thermostat calls for "first-stage" cool-ing, the low voltage control circuit from "R" to "G" and"Y1" is completed. The UCB energizes the blowermotor (if the fan switch on the room thermostat is set inthe "AUTO" position) and drives the economizer damp-ers from fully closed to their minimum position. If theenthalpy of the outdoor air is below the setpoint of theenthalpy controller (previously determined), "Y1" ener-gizes the economizer. The dampers will modulate tomaintain a constant supply air temperature as moni-tored by the discharge air sensor. If the outdoor airenthalpy is above the setpoint, "Y1" energizes com-pressor #1 and condenser fan motor #1.When the thermostat calls for "second-stage" cooling,the low voltage control circuit from "R" to "Y2" iscompleted. The UCB energizes the first availablecompressor. If the enthalpy of the outdoor air is belowthe setpoint of the enthalpy controller (i.e. first stagehas energized the economizer), "Y2" will energize