Reznor ZQYRA Unit Installation Manual - Manual (Page 32)

Form I-ZQYRA P/N 260414R5, Page 32
Outside Air Temperature Failure Alarm - A specific alarm is initiated to indicate sen-
sor failure, and the unit mode shows “ Cripple” on the summary page. The controller
then stops the wheel and uses the wheel discharge temperature to determine the cor-
rect outside air temperature. The system will “hold” the wheel discharge temperature
and will restart the wheel. The controller will stop the wheel every two hours to verify
the outside air temperature and proper operation of the unit.
Wheel Discharge Temperature Failure Alarm - A specific alarm is initiated to indicate
sensor failure, and the unit mode shows “ Cripple” on the summary page. The control-
ler will stop the heat pump and will verify the wheel discharge air temperature. The
controller will hold this temperature and will then restart the heat pump. The controller
will stop the heat pump every hour to verify the wheel discharge air temperature.
Wheel Discharge Air Humidity Failure Alarm - A specific alarm is initiated to indicate
sensor failure, and the unit mode shows “ Cripple” on the summary page. The system
will lock the humidity to 100%.
Heat Pump General Alarm - The system has a hardwired digital input (DI-4) that
monitors a general alarm from the heat pump modulation controller. Whenever that
contact closes, the system will initiate a specific alarm of heat pump failure, and the
unit mode shows “Cripple” on the summary page. The unit will run in cripple operation
until one of the following conditions occurs: The wheel discharge air dewpoint is above
the High Dewpoint Limit setpoint ( Hi Dewpt SP = 68°F/20°C); the wheel discharge air
temperature is above the High Discharge Air Temperature Limit setpoint ( Hi Temp SP
= 85°F/29.5°C); or the wheel discharge air temperature is below Low Discharge Air
Temperature Limit setpoint ( Lo Temp SP = 48°F/9°C). If any of the above conditions
occur, the unit will run the restart sequence.
Unit Discharge Air Temperature Sensor Failure Alarm - If the discharge air sensor
fails, a specific alarm is initiated to indicate sensor failure, the heat pump is disabled,
and the unit mode shows “Cripple” on the summary page. The unit will run in cripple
operation until one of the following conditions occurs: The wheel discharge air dew-
point is above the High Dewpoint Limit setpoint ( Hi Dewpt SP = 68°F/20°C); the wheel
discharge air temperature is above the High Discharge Air Temperature Limit setpoint
( Hi Temp SP = 85°F/29.5°C); or the wheel discharge air temperature is below Low Dis-
charge Air Temperature Limit setpoint ( Lo Temp SP = 48°F/9°C). If any of the above
conditions occur, the unit will run the restart sequence.
Reversing Valve Failure Alarm - The system verifies operation of the reversing valve
by comparing the actual operation to expected operation during the commanded mode
of operation (Heat/Cool). If the system determines a reversing valve failure, the unit will
shutdown the heat pump for the minimum compressor off time and then try to restart
the compressor. The system will initiate a specific alarm to indicate reversing valve
failure. This alarm will automatically be cleared and then logged. After the compressor
restart sequence, if the reversing valve has a second failure, the system will initiate
another specific alarm to indicate reversing valve failure, will shutdown the heat pump,
and the unit mode will show “Cripple” on the summary page.
The unit will run in cripple operation until one of the following conditions occur: The
wheel discharge air dewpoint is above the High Dewpoint Limit setpoint ( Hi Dewpt SP
= 61°F/16°C); the wheel discharge air temperature is above the High Discharge Air
Temperature Limit setpoint ( Hi Temp SP = 85°F/29.5°C); or the wheel discharge air
temperature is below the Low Discharge Air Temperature Limit setpoint ( Lo Temp SP
= 48°F/9°C). If any of the above conditions occur, the unit will run the restart sequence.
Shutdown Mode
The unit also has the ability to shutdown the system to protect the individual compo-
nents. The shutdown mode occurs when one of the following sequences occur:
~ the shutdown digital input (DI-5) is active,
~ the unit has exceeded the allowed amount of time in cripple mode operation,
~ the unit has exceeded the allowed number of restarts,
~ there are multiple sensor failures,
~ the outside air is above the High Outside Air Temperature Limit setpoint,
~ or, the wheel defrost sequence has failed.
8.3 Safeties, Alarms,
and Lockouts
(cont’d)
8.0 Controls
(cont’d)
8.3.1 Service Alarms - Cripple Mode (cont’d)