Error code reference

American Standard Air Conditioner Error Codes

9 error codes documented with diagnostic procedures.

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1Normal operation (LED continuously ON).2No power to the board or the control board has failed.3Compressor failure detected.4Blown fuse detected.5Mode switch or setpoint switch fault, or incorrect thermostat wiring.6Indoor air thermistor fault.7Indoor coil thermistor fault.8Outdoor air thermistor fault (PTHP models only).9Outdoor coil thermistor fault (PTHP models only).

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Step-by-step tests, expected values, wiring diagram references, and verified part numbers.

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