High Lockout
LED2 on PCB 37 on Ideal Classic FF

Your boiler is trying to light but the flame is cutting out almost immediately, which is usually caused by a dirty sensor or a problem with the gas supply.

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

Goes off during an ignition trial period.

What causes this fault?

This fault occurs when the boiler's control system fails to detect a stable flame after it attempts to light. The most common reason is a coating of carbon or dirt on the sensing probe which prevents it from 'seeing' the fire, or a restriction in the gas supply preventing a strong enough flame from forming.

This issue can be more frequent during the first cold snap of autumn when debris has settled on the electrodes after a summer of inactivity.

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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