Outside Sensor Fault Low

Keston Outside Sensor Fault Fault Code

Also written as OUTSIDESENSORFAULT — same fault.

The Keston Outside Sensor Fault fault code means: your boiler has lost the connection to the weather sensor outside, so it is currently relying on default internal settings rather than adjusting your heating based on the temperature outdoors.. It appears on 5 Keston models in our database.

Monitor it

This is a minor fault. Keep an eye on it and mention it at your next annual boiler service. Reset the boiler and see if it clears.

Technical description: Fault detected in the external temperature sensor
Typical repair cost £120-200 (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 Outside Sensor Fault fault code

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

Source

Keston Outside Sensor Fault 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