High Lockout
L-F on Ideal Mexico HE

Your boiler has failed to light or maintain a flame, meaning your heating and hot water have stopped working.

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

Flame failure

What causes this fault?

This fault occurs when the boiler's control system attempts to start the burner but cannot detect a stable flame. The most common reasons are a lack of gas supply to the unit, a worn-out ignition component that fails to create a spark, or a dirty internal sensor that cannot 'see' the flame once it has lit.

This fault is more common during the first cold snap of winter, as gas valves can occasionally stick after long periods of inactivity during the summer.

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
Search the official register →

Related guides you might find useful