Rinnai Non-SENSEI Code 32
Outgoing water temperature thermistor fault. The sensor that reads the temperature of the water leaving the unit is out of range or not reporting. Rinnai's procedure is the standard thermistor one: check the harness, drain the unit, pull the sensor and clean any scale off it, then compare its resistance against the published curve — 11.4 to 14K ohms at 59°F, falling as it warms.
Part replacementThe verdict
Replace a part
A sensor, not the heat exchanger. Cleaning scale off it sometimes fixes it outright, which is a hint about the water rather than the part. The component is inexpensive; most of the cost is the visit.
Typical cost: $150–$450
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. 37), read Aug 2026 — the manufacturer's own documentation for this exact series.
What you can safely check
- Note when the unit was last descaled. Rinnai's own procedure starts by cleaning scale off this sensor, so a scaled unit makes this fault more likely to return.
- Book a service call — the sensor sits in the water path and the unit has to be isolated and drained to reach it.
Code 32 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
3 other Rinnai Non-SENSEI codes point at a thermistor 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: