American Standard AC & Heat Pump

American Standard AC & Heat Pump Error Code Red 12 Flashes

Troubleshooting guide for the American Standard AC & Heat Pump system fault Red 12 Flashes.

What It Means

Liquid line pressure transducer open or shorted.

Possible Causes

  • Damaged or loose pressure transducer wiring.
  • Defective liquid line pressure transducer.

Not sure which one it is — or if it's none of these? Try ACLogics today.

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.
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Full Diagnosis

Liquid line pressure sensor fault (open or shorted).

All Recorded Causes

Check the wiring to the pressure transducer. Replace the sensor if confirmed bad; a technician should verify system pressures and operation.

Verify Before Replacing Parts

  1. Confirm the exact American Standard model family and ac and heat pump context before acting on a generic code description.
  2. Verify airflow first, then confirm operating pressures and temperature relationship before adjusting charge, since check the wiring to the pressure transducer.
  3. Look for restrictions, iced coils, or dirty heat-transfer surfaces that can mimic a charge problem, and separately confirm replace the sensor if confirmed bad; a technician should verify system pressures and opera….
  4. After the correction, run the system long enough to confirm the ac and heat pump fault does not return under normal load.

Not sure which system this American Standard code is on?

ACLogics has guided diagnostics for 36 American Standard fault codes and asks the right questions to narrow it down.

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