BoilerFaultCodesTechnical description
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What causes this fault?
This sequence occurs when the boiler is first switched on or regained power after a cut, signalling that the internal control board is testing its electronic components. It is a standard self-diagnostic phase where the system verifies everything is safe before allowing the burner to light. No physical part has failed; the boiler is simply conducting a required safety handshake.
DIY fix possible
Wait for approximately 30 to 60 seconds for the sequence to finish.If the code persists for more than 5 minutes, turn the power off and back on at the fused spur.Ensure the boiler condensate pipe is not frozen if this occurs during extreme cold weather.
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