The High Temp Alarm is triggered when the indoor temperature exceeds temperature setpoint + high temp alarm trigger (default = 16°F). This alarm has a built in 1-minute delay, which can be changed at F35 under L05 Menu if using the PLD or at P8 in the User Menu if using the PGD.
|Component to Check
|Reduced cooling capacity
|Filter, condenser coil, low side pressure.
|Clean/wash filter and condenser. Remove blockage if appropriate. Leak check/ repair if low on refrigerant.
|Improper value set for high temp alarm trigger
|Ht under E menu or other thermostat used to monitor high temperature
If using the pGD, this parameter can be accessed from User Menu – P8
|Default = 18°F above the main setpoint.
|Check if the heat load of the site exceeds sensible capacity of the AC units
|Add/Upgrade AC or reduce heat load by turning off unused equipment
|Cooling command not given by controller
|Check for other alarms present on controller.
Use D52/D57 under C Menu to view current compressor command for unit1/unit2 respectively
|Correct other alarms that would prevent compressor start up, such as high/low pressure lockout and smoke/fire alarm.
|Improper value set for compressor turn on
|Lead compressor turn on: C02 under E menu
Lag compressor turn on: F38 under L05
If using the pGD, these parameter can be accessed under User Menu.
|Correct compressor settings.
|Compressor circuit failure
Compressor contactor (KM1)
Compressor run caps (C)
Compressor circuit wiring
|Replace failed component.
Correct/tighten wiring according to the Compressor Circuit diagram.
|Indoor temperature sensor
|Indoor temp sensor (ST1)
Indoor temp sensor calibration (N2A under C menu)
Backup Indoor temp sensor (ST2)
Backup indoor temp sensor calibration (N42 under C Menu)
If using the pGD, calibrations can be accessed in Maintenance Menu
|Verify sensor operation.