Applies to: SENSEI SENSEI RX/CX Non-SENSEI
What you can safely check
- No user fix – call a technician.
What a technician will look at
Everything past the checks above involves gas pressure, live electrical parts or opening the sealed cabinet. That work is for a licensed gas or plumbing professional. For code 72, Rinnai’s service steps cover:
- flame rod (cleaning or replacement) and wiring
Smell gas? Don’t touch switches or try to reset the heater. Leave the building and call your gas supplier or 911 from outside.
Source: Rinnai, Troubleshooting Tankless Water Heater Diagnostic Codes (document 100000652), page 60. The code name is Rinnai’s; the explanation is ours. Codes differ between series – check the model on your heater’s rating plate. This site is independent and not affiliated with Rinnai.