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Pub. No. 22-5204-01
Table 2
Troubleshooting
Symptom Possible Cause Action
Display will not come on.
1. Blown fuse or tripped circuit breaker.
2. Furnace power switch OFF.
3. Furnace blower compartment door or panel
loose or not properly installed.
1. Replace fuse or reset breaker.
2. Turn switch to ON.
3. Replace door panel in proper position to engage safety interlock or
door switch.
Temperature display is incorrect. Temperature display needs calibration. Calibrate Sensor - User Setup Step 49.
Cannot set Heating setpoint
above 80 degrees
Deadband between Heating and Cooling set to high Decrease Deadband setting - User Setup Step 42.
"Service" Flashing on and off. Control EEPROM write error. Press any key and Check / Re-enter Setup Choices.
"Service" solid on and "--" in
temperature display.
Indoor temperature sensor open or shorted Replace Control
Temperature setting will not
change. (Example: Cannot set
heating higher or cooling lower).
1. Upper and/or lower temperature limits were
reached.
2. "Keypad locked" is displayed on LCD.
1. Check the temperature setpoints:
Heating limits are 40 - 85F.
Cooling limits are 65 - 90F.
2. Unlock keypad - press Up+Down arrow together until icon disappears.