BoilerFaultCodesYour boiler has shut itself down for safety because it tried to light several times but couldn't maintain a steady flame.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Lockout due to several flame failures
What causes this fault?
This fault occurs when the boiler's control system fails to detect a consistent flame after several ignition attempts, causing it to shut down for safety. The most common reasons are a worn-out sensing probe that can no longer 'see' the flame, or a blockage in the internal drainage system that causes water to back up into the burner.
This issue is more frequent during very cold spells, as frozen external drainage pipes can prevent the boiler from clearing waste water, leading to a flame failure.
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 E04 — no call-out fees, no surprises.
Affiliate links — we may earn a commission at no extra cost to you.
Potterton Powermax HE 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.
Affiliate links — we may earn a commission at no extra cost to you.