BoilerFaultCodesYour boiler has detected an issue with the sensor that monitors water pressure, which means it cannot verify if there is enough water to run safely.
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 fault
What causes this fault?
This fault occurs when the boiler's internal computer loses communication with the sensor that measures water levels within the system. The most common reason is that the sensor has suffered an electrical failure or has become blocked by debris and sludge, preventing it from sending a reliable reading. Because the boiler cannot confirm there is enough water to operate safely without overheating, it shuts down as a precaution.
DIY fix possible
Check the pressure gauge on the front of the boiler; it should be between 1.0 and 1.5 bar.If the pressure is too low, use the filling loop underneath the boiler to carefully top it up.Press the reset button (usually marked with a flame or 'reset') once the pressure is corrected.
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A boiler cover plan would cover faults like F9 — no call-out fees, no surprises.
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