BoilerFaultCodesYour boiler is failing to light the gas to create a flame, meaning you will not have any 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: Refer to fault finding section on Page 30 (displayed when control fails to detect flame after ignition attempts).
What causes this fault?
This fault occurs when the boiler tries to light the gas three times but fails to detect a steady flame, causing the system to shut down for safety. The most common reasons are a worn-out ignition spark, a dirty sensor that can't 'see' the flame, or a blockage in the gas supply preventing fuel from reaching the burner.
This issue is more frequent during the first cold snap of autumn, as components like the gas valve or electrodes can seize or fail after being dormant over the summer.
DIY fix possible
Check that your gas supply is turned on at the meterPress the 'Reset' button on the control panel to attempt a restartIf you have a prepayment meter, ensure you have active credit
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 A03 — 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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