Rinnai 72 Error Code: Flame rod
Updated October 2026 · Sourced from Rinnai documentation
🛑 Turn it off and call a licensed pro
The flame rod or its wire has a fault. The manual says to check the flame rod and wire and verify the heat exchanger is not leaking.
Is it safe to keep running? No. Turn it off and get it checked. Call a trained and qualified professional (or Rinnai customer support). Do not open the unit.
72 at a glance
| Code / how it shows | Meaning | Applies to |
|---|---|---|
| 72 Code shown on the temperature controller display | Flame rod | SENSEI N Series residential condensing: RU199i, RU180i, RU160i, RU130i (indoor) and RU199e, RU180e, RU160e, RU130e (outdoor) |
Check this first
Only steps a homeowner can do safely. Do not open electrical panels or the burner area.
- Turn off the unit; do not open it.
🛑 Stop and call a licensed pro if
- Call a trained and qualified professional (or Rinnai customer support). Do not open the unit.
- You smell gas. Leave the house, do not touch switches, and call your gas utility from outside.
- Codes for flame failure, overheating, venting or the control board that return after one reset.
- Water leaking from the heater, the relief valve discharging, or scorching around the burner area.
- A carbon monoxide alarm sounds. Get everyone outside and call 911 or the fire department.
Safe first steps for any Rinnai code
- Write down the exact code shown on the controller or the number of status light flashes.
- Turn the water heater power off and back on (or press the reset button the manual describes) once. If the code comes back, stop resetting.
- Make sure the gas supply valve to the heater is open and other gas appliances in the home are working.
- Make sure the cold water supply valve is fully open and hot water taps are not partly closed.
- Look at the outside vent terminal for snow, ice, leaves or anything blocking it (look only).
Source: Rinnai SENSEI N Series Residential Installation and Operation Manual (100000467), 5.6 Diagnostic Codes, p.75. Codes are series-specific, so your unit's own manual is the final word. Reviewed October 2026.
Ryan Giles · Red Seal Certified Plumber · Ask a plumber · Ask an HVAC technician
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