BoilerFaultCodesWhat the manual says
Manufacturer manualIncorrect sensing of flame. Flame detector defective
What causes this fault?
This fault occurs when the boiler's internal sensors detect a flame after the burner should have already shut off, or before it has even started. The most common cause is a moisture buildup or carbon deposits on the sensing electrode, which creates a false electrical signal that tricks the control board into thinking a fire is present.
This fault can be more frequent during periods of heavy rain or high humidity, as moisture entering the flue can interfere with the sensitivity of the electrical ignition components.
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.
Avoid the next call-out bill
A cover plan would handle faults like F.27: no call-out fees, no surprise bills.
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