Medium
F.78 on Glow-worm Energy Regular

Your boiler is struggling to communicate with your hot water controller, which is preventing it from heating your water correctly.

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

Interruption to DHW outlet sensor at external controller. UK link box is connected, but hot water NTC not bridged

From this model's manual
Verified against the Glow Worm Energy Regular installation & service manual, page 30.
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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