Medium
d.40 on Glow-worm Compact

Your boiler is reporting that the water temperature inside the heating system has risen higher than expected.

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

Heating flow temperature

From this model's manual
Verified against the Glow Worm Compact 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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d.41View →F.22View →

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