A107_A Return Air Temp Thermistor Failure
Status
This is a passive alarm, the air handler will operate normally with this alarm.
Description
This alarm is generated when a return air sensor has been installed, then fails or is removed. Customer may silence the audible alarm in thermostat and attempt to reset alarm.
Cause
1. Accessory Return air sensor was installed in system, and has failed.
2. Accessory Return air sensor was installed in system, and is removed.
3. Accessory Return air sensor was never installed in system, and moisture has accumulated on control board and shorted the solder or pins where the return sensor goes and has cleared. This moisture fooled the control into thinking one was installed.
Solution
1. Replace Return Air Sensor.
2. Reinstall Return Air Sensor, or cycle complete power to system and allow it to relearn there is no sensor.
3. Cycle power to system to allow it to relearn that no sensor is installed after verifying control board is dry. Determine cause of condensation on control board. Low air flow, Water blowing off coil.
