BoilerFaultCodesYour boiler has reached an unsafe temperature because the water is not circulating correctly through the system.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Flow/return valves closed, Stuck pump. Boiler has overheated.
What causes this fault?
This fault occurs when the water inside the boiler gets too hot because it cannot flow away from the heat source quickly enough. The most common reasons are a pump that has seized up or internal valves being accidentally left closed, which traps the heat and triggers a safety shutdown.
This fault is more common in autumn when heating systems are switched back on for the first time after being idle all summer, which often leads to the pump seizing.
DIY fix possible
Check that the isolation valves under the boiler are in the open positionEnsure all radiator valves (TRVs) are turned up to fullTry resetting the boiler using the control knob to see if the pump clears the blockage
Find a Gas Safe engineer
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A boiler cover plan would cover faults like 02 — 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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