High outgoing temperature (safety shutdown)
Displayed as: 16
Rinnai's RU series installation and operation manual lists diagnostic code 16 as "High Outgoing Temperature (safety shutdown because water heater is too hot)". The manual's checks are to confirm the fan motor is functioning correctly and to replace the gas valve assembly.
Hot water and scalding
- Water above 49 °C at a tap can scald in seconds, and children and older adults are at most risk. BC's plumbing code limits shower and bathtub water to 49 °C.
- Storage tanks are normally kept hotter (Health Canada advises 60 °C) to limit Legionella growth, with a thermostatic mixing valve tempering the water to the fixtures.
- Never bypass or remove a mixing valve, thermostat or high-limit control to get hotter water.
Official guidance: Government of Canada on water temperature and scalds and HealthLinkBC.
Applies to
This code and wording come from manual 100000467 for the RU series. The cross-series document 100000652 applies the same code across SENSEI and non-SENSEI 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
The unit shut down because the outgoing water temperature exceeded its safety limit. The manual's two directions are airflow (a failing combustion fan lets heat stack in the exchanger) and fuel delivery (the gas valve assembly passing too much gas). Both checks are technician work, and the manual directs replacing the gas valve assembly after the fan is confirmed good.
Same code, other equipment
- Rinnai non-SENSEI series: Same meaning per troubleshooting document 100000652. Source
Safe things to observe
- Note whether the water at the taps was hotter than its setting before the shutdown.
- Check the vent termination for blockage, which can produce the same overheating pattern.
Do not
- Do not reset the unit repeatedly and continue drawing hot water.
- Do not raise the temperature setting to work around the shutdown.
- Do not replace the gas valve before the fan check is done.
How professional service helps
- A technician confirms the combustion fan motor and airflow, then tests and replaces the gas valve assembly per the manual.
- Venting and the temperature sensors are verified at the same visit.
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
What should I do if the water was scalding hot before code 16?
Stop using the hot water, confirm the unit is off, and call. A tankless unit that overshoots its safety limit needs fan and gas-valve testing before it is relied on again.
Is code 16 the same as code 14?
Both are overheat codes but different sensors: code 14 is the heat exchanger overheat switch, code 16 is the outgoing-temperature safety shutdown.
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
Facts checked September 7, 2026. Last updated September 7, 2026. Technical reviewer: not yet assigned.