High Lockout
E133 on Potterton Promax System HE Plus

Your boiler has failed to light because it either cannot get enough gas or cannot detect a flame once ignited.

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

Interruption Of Gas Supply or Flame Failure (Gas supply interrupted, ignition failed or flame not detected)

What causes this fault?

This fault occurs when the boiler attempts to ignite but cannot establish or maintain a steady flame. The most common reasons include a lack of gas reaching the burner, a faulty ignition spark, or a sensor that is too dirty to detect that the flame has successfully lit.

This fault is more frequent during extreme cold spells because the external condensate pipe can freeze, causing a backup that prevents the boiler from 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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