How do I fix American Standard error code Red 1 Flash?

Cycle system power to reset any transient fault. If the error returns, inspect the low-voltage communication wiring between outdoor and indoor units for loose connections or damage. In AccuLink systems, error 91 indicates a persistent communication loss; a technician should check the control board and thermostat module.

American Standard | AC and Heat Pump

Error Code Red 1 Flash

Troubleshooting guide for the American Standard AC and Heat Pump system fault Red 1 Flash.

Disclaimer: This information is for general reference. Error codes can vary by model and production year. Always refer to your machine's specific manual and the information printed on the unit itself.

System Diagnosis

Excessive communication errors. (Often accompanied by Error 90/91 on communicating thermostats.)

Potential Causes & Solutions

Cycle system power to reset any transient fault.
If the error returns, inspect the low-voltage communication wiring between outdoor and indoor units for loose connections or damage.
In AccuLink systems, error 91 indicates a persistent communication loss; a technician should check the control board and thermostat module.

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