BoilerFaultCodesYour boiler has stopped working because it cannot detect the necessary water movement to start the heating process safely.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: No pressure change detected when starting the pump
What causes this fault?
This fault occurs when the boiler's internal computer tries to start the pump but doesn't see the expected jump in water pressure to prove water is moving. The most common cause is a sensor that has become blocked with sludge or debris, though it can also happen if the pump itself has seized or failed. Essentially, the boiler shuts down as a safety precaution because it cannot confirm that water is circulating correctly through the heat exchanger.
This issue is more frequent in autumn when the heating is turned on for the first time after summer, as the pump and sensor are prone to sticking after long periods of inactivity.
DIY fix possible
Check the pressure gauge and top it up to 1.5 bar if it is lowReset the boiler using the flame/reset buttonEnsure all radiator valves are open
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A boiler cover plan would cover faults like F.75 — no call-out fees, no surprises.
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