BoilerFaultCodesYour boiler has reached an unsafe temperature and has shut itself down to prevent damage.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Overheating (Water system / Temperature control)
What causes this fault?
This fault occurs when the water inside the boiler gets too hot, causing a safety switch to cut the power to prevent internal damage. The most common reasons are a failed pump that isn't moving water away from the boiler quickly enough or a buildup of sludge and debris blocking the internal pipework.
This issue often surfaces during the first cold spell of autumn when the heating is turned back on after being idle all summer, which can cause internal pumps to seize.
DIY fix possible
Check that all radiator valves are fully openEnsure the system pressure is within the normal rangePress the manual reset button once the unit has cooled down
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 Indicator sequence: Slow Flashing — no call-out fees, no surprises.
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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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