Boiler intermittently shuts down with E012, often during high demand
Safety Warning
This repair may involve working with high voltage components or water connections. Always unplug the appliance before removing any panels.
If you are not confident in your ability to perform this repair safely, we strongly recommend contacting a professional technician.
Possible Causes
How to Fix / Troubleshooting
Safety first: Shut off gas and power before accessing burner or gas components. Combustion adjustments must be done by qualified personnel.
- Step 1 – Check vent and air supply: Ensure intake and exhaust are clear and that the boiler has adequate combustion air (no tightly sealed room without make‑up air).
- Step 2 – Clean burner and flame rod: Remove and clean the burner surface and flame rod as described for E003. Ensure all burner ports are clear.
- Step 3 – Gas supply verification: Have a licensed technician measure gas pressure at the inlet and manifold during operation. Correct any supply issues or regulator problems.
- Step 4 – PCB and wiring: Inspect flame rod wiring to the PCB. If wiring is intact and gas/air are correct, the PCB flame sensing circuit may be faulty and require replacement.
Do not continue resetting the boiler repeatedly without addressing the underlying combustion issue.
Repair Difficulty
Required Part
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