Rinnai SENSEI Code 61
Combustion fan motor fault. The fan supplying combustion air is not turning, not turning freely, or not reporting correctly. Rinnai checks the wiring harness, whether the blower wheel spins freely, debris in the fan housing, the check valve behind the fan sticking closed, and then motor winding resistance.
Call a proThe verdict
Call a licensed plumber
A real part at a real price, sitting in the combustion air path. Rinnai's own warning on this code is never to plug or unplug the motor with power connected. If the motor checks out, the next suspect is the PC board.
Typical cost: $250–$900
US estimate for parts and labor. Prices vary by region and by who does the work — see how we estimate costs.
What the manual says
The meaning above is transcribed from the manufacturer's diagnostic documentation for the SENSEI — not averaged across the brand.
Source: Rinnai Troubleshooting Tankless Water Heater Diagnostic Codes (100000652) (p. 52), read Aug 2026 — the manufacturer's own documentation for this exact series.
What you can safely check
Before anything else: if you smell gas, stop here, leave, and call your gas utility.
- Turn the unit off at the controller and at the breaker.
- Note whether you heard anything unusual before it failed — a rattle or a whine points at the blower wheel or bearings.
- Book a licensed professional.
Frequently asked questions
Could it just be debris?
Sometimes. Rinnai's steps include inspecting the blower wheel and housing for debris preventing it turning, and the check valve behind the fan sticking closed — both cleaning jobs, but both still need the unit opened with power and gas off.
Code 61 on other Rinnai series
The same code number can mean something different on another series — make sure you're reading the page for your exact unit: