BoilerFaultCodesTechnical description
Fault: Flame signal unstable - Flame monitor reports an unstable flame signal
What causes this fault?
This fault occurs when the boiler's control system cannot detect a consistent, healthy flame after the burner has ignited. The most common reasons are a worn-out sensing probe that can no longer 'see' the flame, or a gas valve that isn't delivering a steady flow of fuel to keep the burner lit.
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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