80 High

Keston 80 Fault Code

The Keston 80 fault code means: your boiler has stopped working because it is unable to accurately read the temperature of the water or the exhaust gases, forcing it to shut down for safety.. It appears on 1 Keston model in our database.

Call an engineer soon

Book a Gas Safe engineer within 24 to 48 hours. Your boiler may be unsafe or could break down completely if left.

Technical description: FLOW & FLUE THERMISTOR FAULT
Typical repair cost £150-250 (including labour)

Engineer required

This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.

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Keston models that show the 80 fault code

Click a model for the full fault code list and model-specific repair notes.

Source

Keston 80 fault code information on this page is sourced and cross-checked against the official Keston service / installation manuals for each affected model.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 7 July 2026