High
F12 on Glow-worm Xtramax HE

Your boiler's main control board has lost connection with the display screen, meaning the system cannot receive instructions and has stopped working.

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.

What the manual says

Manufacturer manual

User interface (display) communication error.

From this model's manual
Verified against the Glow Worm Xtramax He installation & service manual, page 33.
Plain-English guidance below. Severity, DIY steps, costs and parts are our interpretation to help you act, not text from the manual.

What causes this fault?

This fault occurs when the digital conversation between the boiler's internal computer and the front display screen is interrupted. It is usually caused by a loose wiring connection or a component failure on one of the circuit boards, preventing the boiler from receiving your temperature settings.

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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