BoilerFaultCodesYour boiler has reached an unsafe temperature and has shut itself down to prevent damage to the internal components.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Overheating
What causes this fault?
This fault occurs when water cannot circulate through the boiler quickly enough to carry heat away, causing the internal temperature to spike. The most common reasons are a failed pump that isn't pushing water, a blockage caused by sludge buildup, or air trapped within the system.
This issue is more frequent when heating is first turned on after summer, as the pump can seize up during long periods of inactivity.
DIY fix possible
Check if any radiator valves have been accidentally closed and open them fullyEnsure your system pressure is between 1 and 1.5 bar on the pressure gaugeGently bleed your radiators to remove any trapped air that might be blocking water flow
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 54 — no call-out fees, no surprises.
Affiliate links — we may earn a commission at no extra cost to you.
Worcester Bosch WR325 RSF 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.