Air supply or exhaust blockage, or full condensate trap
Displayed as: 10
Rinnai's RU series installation and operation manual lists diagnostic code 10 as "Air Supply or Exhaust Blockage / Condensate Trap is Full". The manual's checks are: ensure the condensate line is not blocked; ensure the internal air filter is clean with no obstructions (indoor units); ensure the high-altitude setting is correct; ensure the combustion-air and exhaust vents are not blocked and that approved venting materials are used (indoor units); ensure the vent length is within limits (indoor units); check the fan for debris and that the wheel turns freely; and verify the check valve is not stuck between the fan casing and burner body.
If a carbon-monoxide alarm sounds
- Leave the building immediately and get fresh air.
- Call 911. Do not go back inside until emergency services say it is safe.
- Have every fuel-burning appliance and its venting inspected before use.
Official guidance: Health Canada on carbon monoxide.
Applies to
This code and wording come from manual 100000467, which covers the indoor RU199i, RU180i, RU160i and RU130i and the outdoor RU199e to RU130e. Rinnai's cross-series troubleshooting document 100000652 applies the code across the SENSEI and non-SENSEI tankless generations.
- Rinnai SENSEI RU (Super High Efficiency Plus condensing)
- Rinnai RU130iN
- Rinnai RU160iN
- Rinnai RU180iN
- Rinnai RU199iN
Control platform: Rinnai PC board with digital controller display. Source manual: 100000467 (rev. 07 on rinnai.ca) (2020–2021).
Why a code is not a diagnosis
Code 10 groups three families of cause: a blocked or frozen vent termination, a full or blocked condensate trap or drain line, and a fan or check-valve fault. The code does not say which; the manual's checks walk through them in order, and several are technician procedures.
Same code, other equipment
- Rinnai non-SENSEI series (V, RL, RUCS/RUS): The same number means the same air-supply or exhaust fault family per troubleshooting document 100000652, with the same checks. Source
- Navien and other brands: Code numbers are brand-specific; a 10 on other equipment is read against that unit's own manual.
Safe things to observe
- Look, without touching anything, for a blocked or iced vent termination outside and clear debris you can see from ground level only if safe.
- Check the unit's condensate line for a visible kink or blockage at the drain point.
- Note whether the code clears after a reset and returns only after a period of running, which points to a recurring airflow or condensate cause.
Do not
- Do not run the unit with a blocked vent or bypass the condensate trap.
- Do not open the fan housing or burner to clear debris yourself.
- Do not extend the vent run beyond the manual's length tables.
How professional service helps
- A licensed gas fitter checks the vent run and termination against the manual's length and material tables and clears any blockage.
- The condensate trap and drain are cleaned and verified, and the internal air filter is cleaned or replaced.
- The combustion fan, wheel and check valve are tested, and the high-altitude setting is verified against the installation altitude.
Diagnostic visit
Repair visits carry a diagnostic service fee that CANRO states is credited toward the repair if you proceed. The amount is confirmed by phone; it is not published. Source, checked September 7, 2026.
Where CANRO provides on-site service
On-site service is currently offered across Metro Vancouver: Vancouver, Burnaby, Richmond, Surrey, Coquitlam, North Vancouver, West Vancouver, New Westminster, Delta, Langley, Port Moody, Port Coquitlam, Maple Ridge, Pitt Meadows, White Rock, Tsawwassen; plus Anmore, Belcarra, Lions Bay, Bowen Island, Abbotsford with travel or ferry arrangements confirmed by phone. Everything else on this site is reference information you can use anywhere in Canada.
Frequently asked questions
Can code 10 be caused by winter weather?
Yes. An iced or snowed-over vent termination blocks the exhaust path and produces exactly this code. Clear the termination if you can do so safely, then reset the unit once.
Is code 10 a carbon-monoxide risk?
The unit locks out rather than running with a blocked vent, which is the safe direction. If a carbon-monoxide alarm is sounding, leave the building and call 911; otherwise the blockage checks come first.
What is the difference between codes 10 and 17?
Code 17 is documented as venturi blockage: if the code 10 solutions do not correct the problem, the venturi itself is checked. Code 10 is the broader airflow and condensate family.
Locked out with no hot water? Call with the code ready.
The brand, model and this code are passed along when you request service online, so the technician arrives prepared.
On-site service in Metro Vancouver, BC. Call to check availability.
Sources and verification
- Rinnai RU series Installation and Operation Manual, section 5.6 Diagnostic Codes · 100000467 · accessed September 7, 2026
- Rinnai Troubleshooting Tankless Water Heater Diagnostic Codes · 100000652 · accessed September 7, 2026
- Rinnai Canada — RU199iN product page · Canadian source · accessed September 7, 2026
Facts checked September 7, 2026. Last updated September 7, 2026. Technical reviewer: not yet assigned.