High Lockout
F9 on Glow-worm 30ci Plus

Your boiler has stopped working because it cannot correctly detect the water pressure, which is usually caused by a faulty internal sensor rather than a leak.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed

Call an engineer soon

Book a Gas Safe engineer within 24 to 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 water pressure sensor or receives an illogical reading from it. The most common reason is that the sensor itself has developed an electrical failure or has become blocked with debris, meaning the boiler can no longer verify that it is safe to fire up.

Engineer required

This is a high severity fault. Stop using the boiler and call a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.

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Related fault codes

F8View →

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