High Lockout
S.03 on Glow-worm Flexicom cx

Your boiler is struggling to light the flame correctly, meaning your heating and hot water may not work reliably.

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 attempts to start up but fails to establish or maintain a stable flame during the ignition sequence. The most common reasons are worn-out sparks that cannot light the gas or a faulty sensor that fails to detect the flame once it is 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.

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