Carrier 48/50PD05 User Manual

20Quality (IAQ) section of the Economizer Operation section abovefor more details on Demand Control Ventilation (DCV).Economizer Operation for Units Equipped with Return AirCO 2 Sensor OnlyWhen the CO 2 sensor detects a CO 2 level or IAQ Level(Inputs→AIR.Q→IAQ) below the AQ Differential Low(Configuration→AIR.Q→AQD.L) value the MP.25, MP.50,MP.75 and MP.MX points will be recalculated to new values forMP.25, MP.50, MP.75 based on the Econ Min IAQ Position(Configuration→AIR.Q→AQ.MN). The economizer outside airdamper will close and reduce the amount of outside air CFM to theconditioned space based on the lower IAQ sensor readings andindoor fan speed. The economizer outside air damper willcontinue to close and reduce the amount of outside air CFM to theconditioned space until the damper reaches user configurable EconMin IAQ Position (Configuration→AIR.Q→AQ.MN). This willhappen when the Commanded Fan Speed(Outputs→FANS→F.SPD) is at the Supply Fan Maximum Speed(Configuration→UNIT→FS.MX). When the Commanded FanSpeed (Outputs→FANS→F.SPD) is between Supply FanMaximum Speed (Configuration→UNIT→FS.MX) and theSupply Fan Minimum Speed (Configuration→UNIT→FS.MN)the damper will operate in the shaded area of Figure 8 based on theIAQ Level (Inputs→AIR.Q→IAQ).Economizer Operation for Units Equipped with Return AirCO 2 Sensor and outside air CO 2 SensorThe Economizer will operate similar to Economizer Operation forUnits Equipped with Return Air CO 2 Sensor Only but the IAQLevel (Inputs→AIR.Q→IAQ) will be determined by actualoutside air CO 2 measurements instead of the 400 ppm CO 2 defaultvalue for OAQ.Cooling Mode Using Space Temperature Sensor T55,T56, T58 or T59 and Humidistat (HL38MG029 orTSTATCCPLH01--B)Enhanced dehumidifying will be provided when a humidistat(HL38MG029 or TSTATCCPLH01--B) is connected the PD unitterminal strip across the R and W2 terminals (since the PD unitdoes not support the use of conventional thermostat inputs the W2terminal is reconfigured for humidity input) and Space HumiditySwitch (Configuration→UNIT→RH.SW) configuration variableis set to 1 (Normally Open--no call to dehumidify). Relativehumidity set point is set by adjusting the dial on the HL38MG029or TSTATCCPLH01--B device. When the humidistat contactsclose and provide 24VAC to the W2 terminal the PD unit will resetthe Supply Air Control Point (Run Status→COOL→SA.CP) byone degree F lower than the Supply Air Set Point(Setpoint→SASP) or the current control point if the Supply AirSet Point (Setpoint→SASP) has already been modified. After 5minutes if the humidistat contacts are still closed and 24 VAC isbeing supplied to the W2 terminal the PD unit will reset the SupplyAir Control Point (Run Status→COOL→SA.CP) lower by onemore degree F. This reset cycle will continue to lower the supplyair temperature every 5 minutes until the Supply Air Control Point(Run Status→COOL→SA.CP) is equal to the Supply Air SetPoint (Setpoint→SASP) + SASP Maximum Reset Down(Configuration→COOL→SAT→SA.MD). The unit will continueto operate at this reduced supply air temperature control point untilthe humidistat contacts open and 24VAC is no longer supplied tothe W2 terminal. When 24VAC is no longer supplied to the W2terminal the supply air control point will be reset higher by onedegree F. After 3 minutes if the humidistat contacts are still openand 24VAC is not being supplied to the W2 terminal PD unit willreset the Supply Air Control Point (Run Status→COOL→SA.CP)higher by one more degree F. This reset cycle will continue toraise the Supply Air Control Point (Run Status→COOL→SA.CP)every 3 minutes until the Supply Air Control Point (RunStatus→COOL→SA.CP) is equal to the Supply Air Set Point(Setpoint→SASP) or the supply air control point if reset was beingapplied due to cooling requirements that reset the Supply Air SetPoint (Setpoint→SASP). Whenever Relative Humidity Reset isapplied the space temperature is controlled by modulating the fanspeed even if the fan was locked at 100% due to (Setpoint→SASP)reset.Cooling Mode Using Space Temperature Sensor T55,T56, or T58 and Humidity Sensor (HL39ZZ007 or33ZCSENRH--01)Enhanced dehumidifying will be provided when a humidly sensor(HL39ZZ007 or 33ZCSENRH--01) 4 to 20 ma control isconnected the PD unit terminal strip across the TB1--J10 pin 3 and4, power to humidity sensor is connected to R and C, the RHSensor on OAQ Input (Configuration→UNIT→RH.S) is set toYES and Space Humidity Switch(Configuration→UNIT→RH.SW) configuration variable is set to0. Relative humidity set point is set by changing the value ofSpace RH Set point (Setpoint→RH.SP). When the relativehumidity in the space is above the Space RH Set point(Setpoint→RH.SP) the PD unit controls will reset the supply airtemperature by one degree F lower than the Supply Air Set Point(Setpoint→SASP) or the current control point if the Supply AirSet Point (Setpoint→SASP) has already been modified. After 5minutes the PD unit will reset the Supply Air Control Point (RunStatus→COOL→SA.CP) lower by one more degree F. This resetcycle will continue to lower the Supply Air Control Point (RunStatus→COOL→SA.CP) every 5 minutes until the Supply AirControl Point (Run Status→COOL→SA.CP) is equal to theSupply Air Set Point (Setpoint→SASP) + SASP Maximum ResetDown (Configuration→COOL→ SAT→SA.MD). When therelative humidity in the space goes below the Space RH Set Point(Setpoint→RH.SP) -- the Space RH Deadband(Setpoint→RH.DB) the supply air control point will be resethigher by one degree F. After 3 minutes if the humidity sensorreading is still below the Space RH Set Point (Setpoint→RH.SP) --the Space RH Deadband (Setpoint→RH.DB), the PD unit willreset the Supply Air Control Point (RunStatus→COOL→SA.CP) higher by one more degree F. This resetcycle will continue to raise the Supply Air Control Point (RunStatus→COOL→SA.CP) every 3 minutes until the supply airtemperature control point is equal to the Supply Air Set Point(Setpoint→SASP) or the supply air control point if reset was beingapplied due to cooling requirements that reset the Supply Air SetPoint (Setpoint→SASP).Heating ModesGas Heating Mode Using Space Temperature SensorT55, T56, or T58 (48PD Units Only)For gas units, the Type of Heat Installed(Configuration→HEAT→HT.TY) will be factory set to a value of1.Heat will not operate if the outdoor temperature is greater than thevalue configured for the Heating Lockout Temperature(Configuration→HEAT→HT.LO), Heat Minimum On Time(Configuration→HEAT→MRT.H) and Heat Minimum Off Time(Configuration→HEAT→MOT.H). Timeguards apply to bothstages of heating. Factory defaults values are 2 minute s ON and 2minutes OFF. The Integrated Gas Controller (IGC) minimumon--time of 1 minute will be followed even if Heat Minimum OnTime (Configuration→HEAT→MRT.H) is lower and duringService Test.If the indoor fan control is configured to cycle with the heatingdemand by setting Fan ON When Occupied Heat Minimum OnTime (Configuration→UNIT→OC.FN) to NO, the fan will stopafter a delay configured by Fan--off Delay, Gas Heat(Configuration→HEAT→FOD.G). The factory default forFan--off Delay, Gas Heat (Configuration→HEAT→FOD.G) is 45seconds. If the IGC temperature limit switch opens within 10minutes of the end of the gas heat cycle, the next fan off delay will48/50PD