BoilerFaultCodesYour boiler's internal sensor has detected that the water pressure is too high or the sensor itself is sending an incorrect reading.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Water pressure sensor signal in the wrong range (too high)
What causes this fault?
This fault occurs when the boiler's internal sensor detects that the water pressure is far higher than the safe operating limit. The most common reason is that the manual filling loop was left slightly open after topping up the system, or the pressure sensor itself has developed an electrical fault and is sending an incorrect high reading to the control board.
DIY fix possible
Check the digital or manual pressure gauge; if it is above 2.5 bar, you need to reduce the pressure.Ensure both valves on the external filling loop are tightly closed to prevent more water entering.Bleed water from a radiator using a bleed key into a container until the pressure gauge returns to between 1.0 and 1.5 bar.
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A boiler cover plan would cover faults like F.74 — no call-out fees, no surprises.
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