What It Means
Low 24VAC control circuit voltage detected.
Rheem AC & Heat Pump
Rheem AC & Heat Pump Error Code 09
Troubleshooting guide for the Rheem AC & Heat Pump system fault 09.
Possible Causes
- Faulty 24V control transformer.
- Low primary line voltage.
- Thermostat wiring short.
- Overloaded control circuit.
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
Low secondary voltage below normal range.
All Recorded Causes
Low 24VAC control voltage, transformer issue, low line voltage, wiring problem, shorted thermostat/outdoor low-voltage wiring, or control-circuit overload.
Verify Before Replacing Parts
- Confirm the exact Rheem model family and ac and heat pump context before acting on a generic code description.
- Verify current draw, overload status, and control signal before condemning the compressor or drive, given that low 24VAC control voltage, transformer issue, low line voltage, wiring problem, shorted th….
- Look for upstream conditions such as airflow or charge issues that may be pushing the compressor into protection, and check the next candidate on the list.
- 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 Rheem code is on?
ACLogics has guided diagnostics for 57 Rheem fault codes and asks the right questions to narrow it down.
