E.04 – .12 High
Your boiler has detected a flame signal when there shouldn't be one, or it is running too hot to operate safely.
Technical description: Permanent fault. False flame signal, short-term fluctuation of the mains, ionization current present even though there is no flame, the burner remains very hot (CO2 too high) or defective gas/air unit.
Typical repair cost: £120-350 (including labour)
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
Protect yourself from future repair bills
A boiler cover plan would cover faults like E.04 – .12 — no call-out fees, no surprises.
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Parts commonly replaced
- Ionisation electrode
- Gas valve
- PCB (Main control board)
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