High Lockout
S.13 on Glow-worm Flexicom cx

Your boiler is struggling to light the burner properly, which is preventing it from heating your water and radiators.

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

ignition

What causes this fault?

This fault occurs when the boiler's control board sends a signal to start the heating process, but it fails to detect a successful flame within the required timeframe. The most common reasons are a worn-out spark electrode that can no longer ignite the gas, or a faulty gas valve that isn't releasing enough fuel into the burner.

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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