High Lockout
Neon 1 NOT lit on Glow-worm Fuelsaver Complheat 40 55

Your boiler is not receiving electrical power or has shut down because there is not enough water pressure in the system.

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

Fault with mains supply, PCB fuse or low water pressure switch.

What causes this fault?

This fault occurs when the boiler's internal computer loses electrical power or detects that the water level has dropped too low to operate safely. It is often caused by a simple blown fuse on the control board or a leak in the system that has drained the pressure. Without this power or water pressure, the boiler shuts down completely to prevent any internal damage.

This issue often appears in autumn when the heating is turned on for the first time, as cold pipes and radiator bleeding can cause the system pressure to drop.

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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