BoilerFaultCodesTechnical 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.
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.
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