High Lockout
Low neon light on Glow-worm EnergySaver

Your boiler is struggling to maintain a strong flame, which is why it keeps turning off or failing to heat up properly.

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

Low flame indicator.

What causes this fault?

This fault occurs when the boiler's internal sensor detects that the flame is too weak or unstable to safely heat the system. The most common reasons are a worn-out ignition electrode that can't spark correctly or a gas valve that isn't delivering the right amount of fuel to stay lit.

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.

Find a Gas Safe engineer
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