BoilerFaultCodesYour boiler has stopped working because the water pressure is either too high or too low to operate 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 out of range
What causes this fault?
This fault occurs when the boiler's internal sensor detects that the system's water pressure has moved outside of the safe operating window. It is most commonly caused by either a leak in the pipework leading to low pressure, or a failure in the expansion vessel causing the pressure to spike too high when the heating is on.
This issue often appears in autumn when the central heating is first turned on after summer, as the change in temperature can highlight existing pressure losses or failing expansion components.
DIY fix possible
Check the pressure gauge on the front of the boiler or via the digital display.If the pressure is below 1.0 bar, use the filling loop valves to top it up to 1.5 bar.If the pressure is too high, bleed a radiator to release small amounts of water until the gauge returns to 1.5 bar.Reset the boiler once the pressure is within the correct range.
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