High Lockout
E29 on Potterton Powermax HE

Your boiler has detected an internal electrical connection problem that is preventing it from monitoring the system pressure correctly.

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

Fault in link on 6-way plug J11. Replace (pressure sensor) cable assy. Part No. 5107534

What causes this fault?

This fault occurs when the boiler's main control board loses its physical electrical link with the water pressure sensor. It is typically caused by a loose connection at the plug or a break in the internal wiring harness that monitors the system's safety levels. Because the boiler can no longer verify if there is enough water to operate safely, it will shut down as a precaution.

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
Search the official register →

Related fault codes

E28View →

Related guides you might find useful

Boiler keeps losing pressure

Six most common causes of dropping pressure.

Read →

Boiler keeps cutting out

Lockout fault with a reset-needed pattern.

Read →

Yellow or orange flame — CO safety

Safety-critical — turn off, read this.

Read →