High Lockout
4.13 on Ideal Logic Max Heat

Your boiler has lost power or the screen has failed, meaning it will not operate and you cannot see any settings or status messages.

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

No Display

What causes this fault?

This fault occurs when the electrical connection between the boiler's internal computer and the front screen is broken or lost. The most common reason is a failure of the display circuit board itself, or a blown fuse on the main control board caused by an internal electrical surge.

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 guides you might find useful

Boiler won't turn on — 9-step checklist

Work through these before the call-out.

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 →