Medium
Cylinder Thermistor Fault on Keston Heat 45

Your boiler has lost the signal from the sensor that monitors the temperature of your hot water cylinder, meaning it does not know when your water is hot enough.

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

Check Cylinder Thermistor Wiring, Check Cylinder Thmr

From this model's manual
Verified against the Keston Heat 45 installation & service manual, page 53.
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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