f1
Moderate
Rheem · HVAC Systems & Water Heaters
False Flame Detection (Tankless Water Heater)
Quick Answer
Error code F1 on your Rheem HVAC Systems & Water Heaters means: False Flame Detection (Tankless Water Heater). This is usually fixable — see the step-by-step guide below.
Likely Causes
How to Fix It
1
Shut off the gas supply to the tankless unit immediately
2
Check for gas odor near the burner chamber using a combustible gas detector
3
Inspect the flame rod wiring for shorts to ground or other circuits
4
Disconnect the flame rod and verify the error clears
5
If gas is leaking, the gas valve must be replaced. This repair requires a licensed HVAC or plumbing technician
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
Gas valve assembly
Flame rod
Control board
Related Error Codes