BoilerFaultCodesWhat the manual says
Manufacturer manualThere is excessive temperature difference between the flow and return thermistors OR there is a flame signal without there being a flame present.
From this model's manual
Verified against the Glow Worm Energysaver Combi installation & service manual, page 30.
What causes this fault?
This fault occurs when the boiler's internal sensor incorrectly detects a flame after the burner has been told to switch off. This is most commonly caused by a carbon-coated or damaged sensing probe sending a false electrical signal, or a moisture-damaged control board misreading the system's status.
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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