High Lockout
E133 on Potterton Promax Combi HE Plus

Your boiler has failed to light because it isn't receiving enough gas or cannot sense the flame.

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

What causes this fault?

This fault occurs when the boiler tries to ignite multiple times but fails to establish or maintain a steady flame. The most common reasons are a temporary interruption in the gas supply, a blocked pipe, or a worn-out internal component that can no longer create a spark or detect the heat.

This fault is frequently seen during freezing winter temperatures, as the external condensate drainage pipe can freeze and back up, preventing the boiler from lighting.

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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