Low
d.91 on Glow-worm Ultimate 3 25R

Your boiler is currently trying to synchronize its internal clock with a radio signal and is not indicating a mechanical fault.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed

Monitor it

This is a minor fault. Keep an eye on it and mention it at your next annual boiler service. Reset the boiler and see if it clears.

What the manual says

Manufacturer manual

Status DCF77

From this model's manual
Verified against the Glow Worm Ultimate 3 25r installation & service manual, page 32.
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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