High Lockout
F.73 on Glow-worm Energy

Your boiler has lost signal from its internal water pressure monitor, meaning it cannot confirm if there is enough water to run safely.

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 not connected or has short-circuited

What causes this fault?

This fault occurs when the boiler's main control board loses electrical communication with the water pressure sensor. The most common reason is a loose or damaged connection in the internal wiring, or the sensor itself has developed an electrical fault and failed. Without this signal, the boiler shuts down as a safety precaution because it cannot confirm there is enough water to operate without overheating.

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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