BoilerFaultCodesYour boiler has shut down because water is not moving through the system properly, causing it to overheat.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Permanent fault. Critical flow temperature reached, non-existent or insufficient circulation.
What causes this fault?
This fault occurs when the water inside your boiler gets too hot too quickly because it isn't moving through the pipes as it should. The most common reasons are a failed internal pump that can no longer push the water, or a blockage such as a build-up of sludge or debris within the system.
This issue is frequently seen when heating is first turned on in autumn, as internal pump parts can seize up after being inactive during the summer months.
DIY fix possible
Check if your radiator valves are openEnsure the boiler pressure gauge is between 1 and 1.5 barCheck for frozen condensate pipes during cold weatherTry resetting the boiler using the selector switch
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 E.04 – .03 — no call-out fees, no surprises.
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Could it be time for a new boiler?
If repair costs are adding up, a new energy-efficient boiler could be the smarter long-term choice.
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