Takagi Condensing Code 341
Exhaust thermistor fault. The sensor in the exhaust path is not reporting correctly, so the unit no longer knows how hot its flue gas is — the reading behind code 941.
Call a proThe verdict
Call a licensed plumber
The part is cheap; where it sits is what makes this professional. It is in the exhaust path of a gas appliance and it is the sensor that protects against an overheating flue.
Typical cost: $150–$600
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 Condensing — not averaged across the brand.
Source: Takagi Condensing Models On-Demand Water Heater Troubleshooting Guide (p. 13), 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.
- Check the vent terminal outside for obstructions.
- Leave the unit off and book a licensed professional.
Frequently asked questions
How is 341 different from 941?
341 says the exhaust sensor is faulty. 941 says the sensor works and the exhaust temperature is genuinely abnormal. Same sensor, opposite conclusions.
Don't confuse this with
3 other Takagi Condensing 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: