High Lockout
E168 on Potterton Promax

Your boiler has detected an internal electrical error that is preventing it from running safely, and it usually means the main control board is confused or failing.

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

Printed circuit board (PCB) lockout

What causes this fault?

This fault occurs when the boiler's internal computer becomes confused or fails to monitor its own electronic signals correctly. The most common reason is a failing printed circuit board (PCB) that can no longer communicate with the boiler's components, often triggered by power surges or aging electrical components. In some cases, external electrical interference from a faulty pump or loose wiring can also cause the system to shut down for safety.

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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Related fault codes

E110View →E119View →E160View →

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