BoilerFaultCodesTechnical description
Loss of flame during calibration
What causes this fault?
This fault occurs when the boiler's internal computer tries to fine-tune the burner for efficiency but loses the flame signals mid-process. It is usually caused by a dirty or worn-out sensing probe that can no longer 'see' the flame, or a gas valve that isn't providing a steady enough flow for the calibration to complete. In some cases, a blocked flue or unstable gas pressure from the meter can also interrupt this delicate balancing act.
Engineer required
This is a high severity fault. Stop using the boiler and call a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
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