BoilerFaultCodesYour boiler is temporarily cooling itself down after finishing a heating or hot water cycle, which is a normal part of its operation.
This is a minor fault. Keep an eye on it and mention it at your next annual boiler service. Reset the boiler and see if it clears.
Technical description: pump / fan overrun
What causes this fault?
This status occurs when the boiler has just finished heating your home or water and needs to dissipate excess heat from the internal heat exchanger. The internal pump and fan continue to run for a few minutes to circulate water and air, preventing the components from overheating or being damaged by 'heat soak'. This is a built-in safety feature rather than a mechanical failure.
DIY fix possible
Wait for 5 to 10 minutes for the boiler to complete its cooling cycleCheck that your radiator valves are open to allow heat to dissipateIf the code persists for hours, try resetting the boiler
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 S.05 — no call-out fees, no surprises.
Affiliate links — we may earn a commission at no extra cost to you.
Glow-worm Ultracom 24cx 30cx 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.