BoilerFaultCodesYour boiler has detected that the water pressure is either too low or the sensor that monitors it is not communicating correctly.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Water transducer – check system water pressure
What causes this fault?
This fault occurs when the boiler's internal sensor detects that there isn't enough water pressure to safely heat your home, or if the sensor itself has developed an electrical fault. The most common reason is a gradual loss of water through a small leak or from bleeding your radiators, which drops the pressure below the required operational limit. When this happens, the boiler shuts down as a safety precaution to prevent the internal components from overheating.
This fault is slightly more common in autumn when homeowners turn their heating back on after the summer, as the change in temperature can highlight pressure drops or minor leaks that developed while the system was idle.
DIY fix possible
Locate the pressure gauge on the front of the boiler or via the digital screen.If the pressure is below 1 bar, use the filling loop underneath the boiler to carefully top it up to 1.5 bar.Restart the boiler to see if the error clears once the pressure is stable.
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A boiler cover plan would cover faults like E040 — no call-out fees, no surprises.
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Could it be time for a new boiler?
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