Medium
S.39 on Glow-worm Easicom3 Combi

Your boiler is signalling that it cannot detect an active connection to your underfloor heating system, meaning that part of your home heating may not be working.

Book a service

This fault should be looked at by a Gas Safe engineer within the next week or two. It may get worse if left.

What the manual says

Manufacturer manual

Underfloorheatingcontactopen

Shared across the Easicom 3 range
This code is shared by the boilers in this range, which use the same control board. It may not be printed in this exact variant’s manual.
Plain-English guidance below. Severity, DIY steps, costs and parts are our interpretation to help you act, not text from the manual.

Engineer required

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

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Related fault codes

All 90 fault codes on the Easicom3 Combi

Seeing a different code? Every code this model can display, in one place.

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