Rinnai Non-SENSEI Code 52
Modulating solenoid valve (POV) signal fault. Rinnai gives this code a different name on this generation. Here it is "Modulating Solenoid Valve Signal Abnormal (POV)" — the proportional valve that modulates gas flow, checked by unplugging the POV valve and measuring the coil resistance against the technical data sheet for that model, then checking voltage to it while the unit tries to fire. On the SENSEI generations the same number is the gas valve as a whole, with its own reset sequence on the controller; there is no such reset here.
Call a proThe verdict
Call a licensed plumber
A gas valve component. This is the expensive end of the Rinnai code list — an open coil means replacing the gas valve — and nothing about it is a homeowner job.
Typical cost: $400–$1,100
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 Non-SENSEI — not averaged across the brand.
Source: Rinnai Troubleshooting Tankless Water Heater Diagnostic Codes (100000652) (p. 46), 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.
- If you smell gas, leave the area and call your gas utility from outside. Do not restart the unit.
- Get a written quote that says whether the gas valve is being replaced or only the board — the difference is most of the cost.
- Book a licensed professional.
Frequently asked questions
Is there a reset for code 52 on my unit?
Not on this generation. Rinnai publishes a button sequence on the temperature controller to clear code 52 after a gas valve replacement on the SENSEI and SENSEI RX/CX series only. The Non-SENSEI procedure ends at replacing the valve or the PC board.
Code 52 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:
Don't confuse this with
2 other Rinnai Non-SENSEI codes point at a valve too. They are different components in different places, and ordering a part against the wrong one is the most common way this fault gets expensive: