R - A 9
Alert Code Response
Error 67: Temperature sensor fault
Comfort Control = Err 67
User Interface = No Alert Displayed
Outdoor Fault LED = 6 Flash
Problem Description
• Coil temperature sensor fault
Possible Causes/Solutions
• Coil Sensor open or shorted
- Zero or infinite resistance
• Coil Sensor out of range
- Compare resistance value of sensor to chart in
literature
• No output voltage from control board to sensor
- With sensor disconnected, 5vDC should be
measured on control board
Error 79: LPCO fault
Comfort Control = Err 79
User Interface = No Alert Displayed
Outdoor Fault LED = 7 Flash
Problem Description
• (19 SEER) Open low pressure switch
• (16 & 20 SEER) Low pressure cut-out open for third
time within same call (hard lock-out), cycle power to reset
- (Cooling) Suction pressure is below 50psig and OD
temp is above 55°
- (Heating) Suction pressure is below 25psig and OD
temp is above 10°
• (16 & 20 SEER) Low pressure cut-out fault (heat/cool
lock-out)
- (Cooling) Suction pressure below 50psig and OD
temp is below 55°
- (Heating) Suction pressure below 25psig and OD
temp is below 10°
Possible Causes/Solutions
• System low on charge
• (Cooling) Indoor airflow restriction
• (Heating) Outdoor airflow restriction
• Wiring to low pressure switch is either open or shorted
- If power is interrupted to outdoor unit an ERR79 may
be displayed on the comfort control because the low
pressure switch will not be discovered on
communication bus
Error 80: High pressure monitor fault
Comfort Control = Err 80
User Interface = No Alert Displayed
Outdoor Fault LED = 17 Flash
Problem Description
• High pressure monitor fault for fifth time within same
call (hard lock-out), cycle power to reset
- Liquid pressure has risen above 595 PSIG then fell
below 535 PSIG five times within the same call
Possible Causes/Solutions
• (Cooling) Faulty outdoor fan
• (Heating) Faulty indoor blower
• Refrigerant over charge
• (Cooling) Outdoor airflow restriction
• (Heating) Indoor airflow restriction
• Wiring to high pressure switch is either open or
shorted
Error 87: Roll-out fault
Comfort Control = Err 87
User Interface = ROLLOUT OPEN
Furnace Fault LED = 4 Flash
Problem Description
• Open flame rollout
Possible Causes/Solutions
• Air impingement on burners or flame
• Draft inducer not operating properly
• Restricted heat exchanger
• Low outlet gas pressure
To Next Page
Loading...
