Applies to: Non-SENSEI
What you can safely check
- Make sure the gas supply valve to the heater is fully open.
- On propane, check the tank actually has gas in it.
- Protect the heater and its pipes from freezing (power must stay on for freeze protection to work).
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 02, Rinnai’s service steps cover:
- inlet gas pressure and gas type setting
- igniter and ignition wiring
- gas valve and PC board
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 6. 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.