BoilerFaultCodesYour boiler is unable to start its pilot flame or has shut down to prevent the system from getting too hot.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Pilot fails to light. Overheat thermostat not operating.
What causes this fault?
This fault occurs when the boiler's internal safety sensors detect that the unit has become dangerously hot or when the pilot light fails to stay lit. The most common reason is a failing thermocouple that can no longer sense the flame, or a tripped overheat thermostat caused by a circulation issue like a pump failure.
This issue is more common during the first cold spell of autumn, as pump blockages or airlocks often occur after the heating has been switched off all summer.
DIY fix possible
Locate the overheat thermostat reset button, usually hidden under a small plastic cap on the front or bottom panel.Press the reset button firmly until you hear a click.Attempt to relight the pilot light following the instructions on the boiler's internal door.
Find a Gas Safe engineer
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A boiler cover plan would cover faults like A.(6) — no call-out fees, no surprises.
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