BoilerFaultCodesYour boiler has failed to ignite or stay lit after several attempts and requires a manual reset and investigation by a professional.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Final fault code (Refer to section 7.11)
What causes this fault?
This fault occurs when the boiler's control system attempts to start the burner multiple times but cannot confirm that a stable flame has been established. The most common reasons include a lack of gas supply to the unit, a worn-out ignition spark, or a sensor that can no longer detect the heat of the flame. It essentially acts as a safety shutdown to prevent unburnt gas from building up inside the appliance.
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
Find a Gas Safe engineer
Search the official register for a qualified engineer in your area.
Gas Safe Register →Protect yourself from future repair bills
A boiler cover plan would cover faults like 04 — no call-out fees, no surprises.
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Parts for discontinued models can be hard to find and expensive. A new A-rated boiler could save you money on both repairs and energy bills.
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