Applies to: SENSEI Non-SENSEI RH180 hybrid
What you can safely check
- Switch power to the heater off and back on, then open a hot tap. If the code returns, it needs service.
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 05, Rinnai’s service steps cover:
- bypass valve
- related venting and air filter checks (see code 10)
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 10. 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.