BoilerFaultCodesWhat the manual says
Manufacturer manualBoiler at Lock-Out
What causes this fault?
This fault occurs when the boiler has tried to ignite several times but failed to establish or detect a stable flame. The most common reasons are a lack of gas reaching the burner, a worn-out ignition spark, or the internal control board failing to recognize that the boiler has successfully lit.
This fault is slightly more common in winter when increased demand on the gas network or freezing temperatures can affect gas pressure and component reliability.
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 (Flashing): no call-out fees, no surprise bills.
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All 9 fault codes on the Envoy
Seeing a different code? Every code this model can display, in one place.