Rinnai Error Code E12: High limit stat open (Boiler)
Rinnai error code E12 on a boiler means: High limit stat open. It is also called Rinnai diagnostic code E12.
Homeowner? What Rinnai code E12 means for you
Call a technician Your boiler is reporting: High limit stat open. The boiler has locked out or cannot run properly. One reset is fine; if the code comes back, it needs a licensed technician to find the cause.
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.
Call (647) 657-2977Book a service call
Licensed technicians serving Vaughan, Toronto and the GTA.
What does Rinnai error code E12 mean?
Lockout: the supply temperature got too high and the high limit tripped.
Applies to: E50CRN; E75CRN; E75CRP; E110CRN; E110CRP
Common causes of Rinnai code E12
- Air in the system
- Dirty pump impeller
- Dirty internal filter
A technician checks these and 1 other possible causes on site before replacing any part.
Other Rinnai Boiler codes
All Rinnai Boiler error codes →
Rinnai code E12: homeowner questions
What does Rinnai code E12 mean?
High limit stat open. Lockout: the supply temperature got too high and the high limit tripped.
Is it safe to keep using my boiler with code E12?
It depends on the cause. The boiler has locked out or cannot run properly. One reset is fine; if the code comes back, it needs a licensed technician to find the cause.
Can I reset Rinnai code E12 myself?
You can try one reset (power off for 30 seconds, then on). If Rinnai code E12 comes back, the cause is still there and a licensed technician should check it.
Who can fix Rinnai code E12 near me?
Aurora Star Tech Inc. repairs Rinnai boilers in Vaughan, Toronto and across the GTA. Call (647) 657-2977 or book a service call online.
Homeowner help: Boiler Not Heating: What to Check
Troubleshooting guides
- No heat or some zones cold All brands · Boiler
- Automatic de-aeration program (A xx, 17 min) Rinnai · Boiler
- Central heating works, no domestic hot water Rinnai · Boiler
- Change a parameter in the PARA chapter Rinnai · Boiler
- DHW temperature drops Rinnai · Boiler
- Force the burner on for combustion checks (SERV function 1) Rinnai · Boiler
- Heating system warms without a call Rinnai · Boiler
- Hot water works, no central heating Rinnai · Boiler
- Ignition safety test (forced E02 lockout) Rinnai · Boiler
- Insufficient hot water quantity Rinnai · Boiler
- Open the installer level (code C123) Rinnai · Boiler
- Open the parameter settings menu on the PC board Rinnai · Boiler
- Radiators not hot enough or slow to heat Rinnai · Boiler
- Read the technical read-out and error history Rinnai · Boiler
- Reset the SERVICE reminder (8000 h counter) Rinnai · Boiler
- Restore factory parameters (Copy) Rinnai · Boiler
- Venturi reset on the PC board (code 170) Rinnai · Boiler
- View the last nine error codes (DHW + Up) Rinnai · Boiler
Source: Rinnai E-Combi Series Installation & Servicing Instructions (8U516009 V0116), p.71-76 (15.1, 15.3). 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.