BoilerFaultCodesYour boiler is struggling to light its flame or detected a failed start, which may be due to a temporary issue with the gas flow or ignition.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: All Boilers
What causes this fault?
This fault occurs when the boiler's internal computer tries to light the burner but fails to detect a stable flame after several attempts. The most common reasons are a lack of gas reaching the unit, a dirty or worn spark electrode, or a sensor that is unable to confirm the flame is actually lit.
This fault can appear more frequently during the first cold snap of autumn when a boiler has been idle for months and debris or air has settled in the gas line.
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 5P1 — no call-out fees, no surprises.
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Could it be time for a new boiler?
If repair costs are adding up, a new energy-efficient boiler could be the smarter long-term choice.
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