BoilerFaultCodesYour boiler has stopped working because it cannot accurately tell if there is enough water pressure in the system 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: Low Pressure Sensor Error
What causes this fault?
This fault occurs when the boiler's internal computer loses communication with the sensor that monitors water levels. The most common reason is an electrical failure within the sensor itself or a loose connection in the wiring, meaning the boiler shuts down as a safety precaution because it cannot verify if it is safe to fire up.
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
Find a Gas Safe engineer
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A boiler cover plan would cover faults like P21 — no call-out fees, no surprises.
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Could it be time for a new boiler?
If repair costs are adding up, a new energy-efficient boiler could be the smarter long-term choice.
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