High Lockout
E133 on Potterton Promax HE

Your boiler has failed to light, which means it cannot provide the gas flame needed to heat 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 fault

What causes this fault?

This fault occurs when the boiler tries to light but fails to detect a stable flame after several attempts. The most common reasons include a lack of gas reaching the burner, a failure in the spark system that ignites the fuel, or a blockage that prevents the flame from staying lit.

This fault is frequently seen during freezing winter spells, as the external condensate pipe can freeze and back up, preventing the boiler from successfully igniting.

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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