BoilerFaultCodesYour boiler has stopped working and entered a safety shutdown mode, meaning it will not provide heating or hot water until it is reset or repaired.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Boiler at Lock-Out
What causes this fault?
This fault occurs when the boiler has tried to ignite several times but failed to detect a stable flame, leading the system to shut down for safety. The most common reasons are a lack of gas reaching the burner or a worn-out component failing to spark or sense the flame correctly. It essentially means the boiler’s internal computer has lost confidence that it can burn fuel safely.
This fault can be more frequent during the first cold snap of autumn when internal components that have been sitting idle all summer are suddenly stressed or seized.
DIY fix possible
Locate the reset button or control knob on the front panelTurn the knob to the 'Reset' position or press the reset button for 5 secondsWait for the boiler to attempt to restart; if the code returns, contact a professional
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 F (Flashing) — no call-out fees, no surprises.
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Potterton Envoy 30 is discontinued — time for a new one?
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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