Medium
F.91 on Glow-worm Energy Regular

Your boiler has lost the ability to read the temperature of your hot water cylinder because of a faulty connection or wiring issue.

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

Short circuit: Cylinder temperature sensor

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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Related fault codes

F.90View →F.92View →

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