High Lockout
S.23 on Glow-worm Flexicom cx

Your boiler is struggling to light because it cannot detect a steady flame after starting up.

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 successfully creates a spark and ignites the gas, but the flame goes out almost immediately or isn't recognized by the system. The most common reasons are a worn-out sensing probe that can no longer 'see' the flame, or a gas valve that isn't delivering enough fuel to maintain a steady burn.

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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