T085_F - Suction Line Temp Thermistor Failure
Status
This is a critical fault for furnaces that use electronic expansion valve. Suction temperature is used in the algorithm that drives the electronic expansion valve.
Description
This fault indicates the suction temperature sensor is either open or shorted, or has been removed after being installed.
Expected Operation
The fault "T085_F Suction Line Temp Thermistor Failure" will be declared. Cooling operation will struggle due to this fault.
Cause
1. Suction temperature sensor was installed and removed without cycling power.
2. Suction temperature sensor or wiring has failed.
3. Bad furnace control board.
Solution
1. If no suction temperature sensor was ever installed, cycle power to remove fault and check control for indication of condensation that may have temporarily tricked it into thinking one had been installed.
2. Replace suction temperature sensor.
3. Replace furnace control board.
