BoilerFaultCodesTechnical description
No flame signal with high output
What causes this fault?
This fault happens because the boiler’s control system cannot detect a steady flame while the burner is trying to run at full power. It is often caused by a restricted gas supply, a worn-out ignition probe that can no longer sense the flame, or a physical blockage in the burner or flue system. Because the boiler cannot confirm it is burning fuel safely at high speeds, it shuts down as a protective measure.
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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