Noritz Error 12: Flame Loss / Flame Failure During Operation
The burner lit but the flame was lost or could no longer be sensed while the unit was running, so the control shut down combustion. Often related to flame-sensing or an unstable gas/air mixture. We diagnose and repair it across Greater Vancouver — same-day and after-hours.
The burner lit but the flame was lost or could no longer be sensed while the unit was running, so the control shut down combustion. Often related to flame-sensing or an unstable gas/air mixture.
Noritz fault codes can vary by model and series. Use this as a guide — the same code can have more than one cause. Our Technical Safety BC–licensed technicians read the code, confirm it against your unit's manual, and diagnose the true cause before any repair.
Likely causes of Noritz error 12
- Dirty, corroded, or misaligned flame sensor (flame rod) losing flame signal
- Intermittent or low gas pressure during firing
- Restricted intake/exhaust venting causing flame instability
- Cracked or fouled burner affecting flame
- Gas valve or control board fault
What you can safely check
- Confirm the gas supply is on and other gas appliances are working normally
- Check that vent terminals outside are unobstructed
Beyond these checks, do not open the unit or touch gas/electrical parts — BC law requires a licensed gas fitter. Call us for a proper diagnosis.
Error 12 usually leaves you without heat or hot water and can indicate a safety-related fault. Don't keep resetting it — call for priority after-hours Noritz repair.
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For your safety and to keep your manufacturer warranty valid, BoilerPart.ca does not sell loose boiler parts over the counter or for self-installation. Under BC regulations, gas appliance components must be installed by a licensed gas fitter. Every part we source is genuine OEM and is professionally fitted, tested, and certified by our Technical Safety BC–licensed technicians as part of a complete repair or installation.
Parts often behind Noritz error 12
Genuine Noritz parts we supply and professionally install — never for DIY.
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Noritz Error 12 Repair Across Metro Vancouver
Frequently Asked Questions
Fix Noritz Error 12 Today
Licensed Noritz diagnosis and repair with genuine parts — same-day and after-hours across Greater Vancouver.
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