R
c7
Moderate
Rheem · HVAC Systems & Water Heaters
Flame Rod Issue (Tankless Water Heater)
Quick Answer
Error code C7 on your Rheem HVAC Systems & Water Heaters means: Flame Rod Issue (Tankless Water Heater). This is usually fixable — see the step-by-step guide below.
Likely Causes
  1. Flame rod dirty or oxidized reducing flame detection sensitivity
  2. Flame rod positioning incorrect relative to the burner flame
  3. Flame rod insulator cracked allowing current leakage
  4. Low gas pressure producing a weak flame that the rod cannot detect reliably
How to Fix It
1
Remove the flame rod and clean it with fine emery cloth or Scotch-Brite pad
2
Inspect the flame rod ceramic insulator for cracks or damage
3
Verify the flame rod is positioned correctly per the manufacturer's installation guide
4
Measure flame current during operation (should be above 1.0 microamps)
5
Check gas pressure at the unit's gas inlet and compare to the specified minimum
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
Flame rod
Flame rod gasket
Emery cloth
Related Error Codes
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