Connection High

Glow-worm Connection Fault Code

Also written as CONNECTION — same fault.

The Glow-worm Connection fault code means: your boiler's internal control screen is unable to talk to the main computer brain, meaning it cannot receive the instructions needed to heat your home.. It appears on 3 Glow-worm models in our database.

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 communication between the printed circuit board (PCB) and the user interface
Typical repair cost £180-350 (including labour)

Engineer required

This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.

Find a Gas Safe engineer

Search the official register for a qualified engineer in your area.

Gas Safe Register →

Glow-worm models that show the Connection fault code

Click a model for the full fault code list and model-specific repair notes.

Source

Glow-worm Connection fault code information on this page is sourced and cross-checked against the official Glow-worm service / installation manuals for each affected model.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 27 April 2026