Carrier 48/50HC04---14 Controls, Start-up, Operation And Troubleshooting Instructions

Carrier 48/50HC04---14 Controls, Start-up, Operation And Troubleshooting Instructions Manual pdf 14 page image

14Dehumidification TestFor units with the factory Reheat option, thedehumidification relay is used to change the output statusto operate the circuits in different Reheat modes.Dehumidification relay on by itself puts all circuitsrunning in Hot Gas Reheat dehumidification mode;dehumidification relay on and the cooling test(compressor test relays) on puts unit and or individualcircuits in subcooling dehumidification mode. The fansand heating service test outputs are reset to “Disable” forthe dehumidification service test. Indoor and outdoor fansare controlled normally to maintain proper unit operation.All normal cooling/dehum alarms and alerts arefunctional.Power Exhaust TestThis point allows the board’s power exhaust (PE) outputto be manually turned On (Enable) and Off (Disable).Power Exhaust test can operate simultaneously with otherService Test Points.Economizer TestThis point allows the board’s economizer output to bemanually controlled from 0 to 100 % Open. Economizertest can operate simultaneously with other Service TestPoints.Analog Output 2 TestThis test point activates the AO2 0-10vdc analog output atJ22. These rooftops do not use this output, therefore thistest is not used.NOTE: Service Test Mode does not timeout. Be sure toturn off test mode or cycle power to the RTU to return tonormal operation.ConfigurationThe RTU-OPEN controller’s configuration points effectthe unit’s inputs and operation. Review and understandthe meaning and purpose of each configuration pointbefore changing it from the factory default value. Use theRTU-OPEN Start-up Sheet during configuration; fill inchanged values if changed from factory default. There arethree main configurations menus: SETPOINT, UNIT, andSERVICE. Each configuration point is described belowunder its according menu. See Appendix A for BACviewmenu structure.SetpointOccupied Heating Setpoint -- The heating setpoint thecontroller maintains during the occupied period.Range = 40-90_FOccupied Cooling Setpoint – The cooling setpoint thecontroller maintains during the occupied period.Range = 55-99_FUnoccupied Heating Setpoint – The heating setpoint thecontroller maintains during the unoccupied period.Range = 40-90_FUnoccupied Cooling Setpoint – The cooling setpoint thecontroller maintains during the unoccupied period.Range = 55-99_FEffective Heating Setpoint – The current setpoint valueheating operation will control to.Effective Cooling Setpoint – The current setpoint valuecooling operation will control to.Optimal Start - The earliest time prior to occupancy, atwhich the Optimal Start function may begin to adjust theeffective setpoints. Setting this to 0 will disable optimalstart.Range = 0-4 hours Default = 4 hoursOcc Relative Humidity Setpoint – The space RHsetpoint the controller maintains during the occupiedperiod.Range = 0 to the Unocc RH setpointDefault 60%Unocc Relative Humidity Setpoint – The space RHsetpoint the controller will maintain during theunoccupied period.Range = 30-100% Default = 90%DCV Max Ctrl Setpoint – The difference between indoorand outdoor CO2 level which results in maximumventilation damper position.Range = 0-9999ppm Default = 650ppmPower Exhaust Setpoint – When the economizer damperposition opens above this point the power exhaustoperation will begin. When the damper position fallsbelow this point and 5% lower the power exhaust willshutdown.Range = 20-90% Default = 50%NOTE: This point is only used when ContinuousOccupied Exhaust = NOUnitFan Mode – Sets the operation of the indoor fan when notin cooling or heating mode. Refer to fan operation fordetails on each operation.Range = Auto, Continuous, or Always OnDefault = ContinuousUnit Start Delay – Refers to the time delay the unit willwait after power up or when transitioning fromunoccupied to occupied before it pursues any specificoperation.Range = 0-30 sec Default = 5 secFan Off Delay – Time delay in which the fan willcontinue run after being commanded off.Range = 0-180sec Default = 90secMinimum Cooling SAT – The supply air temperaturemust remain above this value to allow cooling with theeconomizer and/or compressors. There is 5_F plus andminus deadband to this point. If the SAT falls below thisvalue during cooling a compressor stage will be removedand/or the economizer will return to minimum position.Range = 45-70_F Default = 50_FMaximum Heating SAT – The supply air temperaturemust remain below this value to allow heating. There is5_F plus and minus deadband to this point. If the SATfalls below this value during heating the heat stages willbegin to decrease until the SAT has dropped below thisvalue.Range = 95-150_F Default = 120_F