BoilerFaultCodesYour boiler is heating up too quickly and has shut down to prevent damage from overheating.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Excessive temperature rise
What causes this fault?
This fault occurs when the water inside the boiler heats up at an unnaturally fast rate, causing the sensors to trigger a safety shutdown before the unit overheats. The most common reason is a lack of water flow, often caused by a failing internal pump or a blockage in the system that prevents heat from being moved away from the burner quickly enough.
This issue often appears when the heating is first turned on after summer, as the circulation pump can seize up after long periods of inactivity.
DIY fix possible
Check that all radiator valves are fully openEnsure the central heating system pressure is between 1.0 and 1.5 barPress the reset button once the boiler has cooled down
Find a Gas Safe engineer
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A boiler cover plan would cover faults like b25 — no call-out fees, no surprises.
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Vokera Hydra 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.
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