Medium
d.17 on Glow-worm Ultimate3 Combi

Your boiler is struggling to communicate with your heating controls, meaning it may not be receiving the signal to turn your radiators on when you want them to.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed

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

Heatingcontrol

From this model's manual
Verified against the Glow Worm Ultimate3 Combi installation & service manual, page 41.
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

d.18View →d.22View →

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