Icon
Reliable Heating and Cooling Solutions – Quality Service, Fair Prices, Guaranteed Satisfaction!

Rinnai Error Code 341: DHW inlet thermistor fault (Combi Boiler)

Updated · by Aurora Star Tech Inc.

Rinnai error code 341 on a combi boiler means: DHW inlet thermistor fault. It is also called Rinnai diagnostic code 341.

Medium severityCombi BoilerI-Series Plus 150K and smaller · I-Series Plus 175K and higher

Homeowner? What Rinnai code 341 means for you

Check, then call Your combi boiler is reporting: DHW inlet thermistor fault. This is often caused by something simple. Try the safe checks below; if the code returns, book a service call before it turns into a no-heat or no-hot-water emergency.

Safe things you can check yourself

  • Check the thermostat: right mode (Heat or Cool), set a few degrees past room temperature, and fresh batteries if it uses them.
  • Make sure the unit has power: its on/off switch (often looks like a light switch near the unit) is ON and the breaker in the electrical panel is not tripped.
  • Look at the pressure gauge on the boiler. If it reads much lower than usual or near zero, or water is leaking, call a technician.
  • Outside, make sure the intake and exhaust pipes or vent cap are not blocked by snow, ice, leaves or a nest.
  • Check that the boiler gas valve is open (handle in line with the pipe).
  • Try one reset: turn the power off for 30 seconds, then back on. If the code comes back, stop resetting and call a technician.
  • If only hot water is missing, check that the hot water tap is open far enough to start the heater.

Call (647) 657-2977Book a service call

Licensed technicians serving Vaughan, Toronto and the GTA.

What does Rinnai error code 341 mean?

Fault detected in the inlet thermistor, which relates to domestic hot water only.

Applies to: I-Series Plus boilers — 150K BTU and smaller and 175K BTU and higher (Combi)

Common causes of Rinnai code 341

  • Loose, broken or damaged thermistor wiring/connectors
  • Thermistor unplugged (reads -40)
  • Scale or deposits on the thermistor

A technician checks these and 2 other possible causes on site before replacing any part.

Safety: Gas, electrical and refrigerant work must be done by a licensed technician. Turn off power and gas before servicing, never bypass a safety control, and always follow the manufacturer's manual for your exact model.

Rinnai models that use code 341

IP060160CIP090099CIP090160CIP090199CIP120199CIP150199CIP175199CIP199199C

Other Rinnai Combi Boiler codes

CodeMeaning
220Gas valve position not detected (reed switch)
250Condensate pump switch tripped (accessory)
303Secondary system thermistor fault
310Freeze protection thermistor fault
321Outgoing (DHW) water temperature thermistor fault
331Plate heat exchanger thermistor fault (DHW)
353CH supply thermistor fault
363CH return thermistor fault
380Exhaust thermistor fault
393Outdoor temperature sensor fault
400Water pressure sensor communication fault
430High or low system water pressure

All Rinnai Combi Boiler error codes →

Rinnai code 341: homeowner questions

What does Rinnai code 341 mean?

DHW inlet thermistor fault. Fault detected in the inlet thermistor, which relates to domestic hot water only.

Is it safe to keep using my combi boiler with code 341?

It depends on the cause. This is often caused by something simple. Try the safe checks below; if the code returns, book a service call before it turns into a no-heat or no-hot-water emergency.

Can I reset Rinnai code 341 myself?

You can try one reset (power off for 30 seconds, then on). If Rinnai code 341 comes back, the cause is still there and a licensed technician should check it.

Who can fix Rinnai code 341 near me?

Aurora Star Tech Inc. repairs Rinnai combi boilers in Vaughan, Toronto and across the GTA. Call (647) 657-2977 or book a service call online.

Homeowner help: Tankless Water Heater No Hot Water: What to Check · Boiler Not Heating: What to Check

Source: Rinnai Troubleshooting I-Series Plus Boiler Diagnostic Codes (800000375), p.20. Written in our own words as a summary; always check the original manual.

General guidance for qualified technicians. The manufacturer's installation and service manual and local codes always take priority. Aurora Star Tech is not affiliated with, endorsed by or sponsored by any equipment manufacturer; brand and model names are used only to identify equipment and belong to their owners.

Emergency HVAC Service

647-657-2977