High
Lockout LED on Potterton Promax

Your boiler has detected a safety issue and stopped working to protect itself, meaning you currently have no heating or hot water active.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed

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

Indicates that the boiler has locked out. The boiler is fitted with several protection devices and operation of any of these will cause the boiler to 'Lockout'.

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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Related fault codes

E119View →E125View →E133View →

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