High Lockout
E85753 on Potterton Powermax HE

Your boiler's internal valve is unable to switch between heating your radiators and providing hot water, likely because the motor controlling it has failed.

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

Actuator Head

What causes this fault?

This fault occurs when the small electric motor responsible for moving the internal valve becomes jammed or fails electrically. Over time, the internal components can wear out or become stuck due to debris in the heating water, preventing the boiler from switching between heating your home and warming your water.

This fault often becomes apparent during the first cold spell of autumn when the boiler is suddenly required to switch frequently between hot water and central heating modes.

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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