9 flashes
Moderate
Rheem · HVAC Systems & Water Heaters
Polarity Issue
Quick Answer
Error code 9 flashes on your Rheem HVAC Systems & Water Heaters means: Polarity Issue. This is usually fixable — see the step-by-step guide below.
Likely Causes
How to Fix It
1
Use a multimeter to verify proper polarity at the furnace power connection
2
Check voltage between hot and neutral (should be 120VAC)
3
Verify less than 2VAC between neutral and ground
4
Inspect the disconnect switch and junction box wiring for any reversed connections
5
A licensed electrician should correct any upstream wiring issues
Pro Tip
This fix requires some technical knowledge. If you're unsure about any step, consider contacting support or a qualified technician.
Parts You May Need
Wire connectors
Ground wire
Disconnect switch (if faulty)
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