Medium
84 on Keston Heat 45

Your boiler has lost the signal from the sensor that monitors your hot water tank temperature, meaning it cannot accurately control your hot water heating.

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

CYLINDER THERMISTOR FAULT

From this model's manual
Verified against the Keston Heat 45 installation & service manual.
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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