High Lockout
RED NEON on Glow-worm Fuelsaver Complheat 40 55

Your boiler has stopped working because the water pressure in the central heating system is too low.

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

Fill central heating system, pressure 0.7bar min.

What causes this fault?

This fault occurs when there isn't enough water circulating in your central heating system to operate safely. The most common reasons are a slow leak from a radiator valve or pipework, or simply that the system needs topping up after you have bled air from your radiators.

This issue is frequently seen in autumn when homeowners turn their heating back on for the first time after summer, revealing pressure drops that occurred while the system was idle.

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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