46 High

Johnson Starley 46 Fault Code

The Johnson Starley 46 fault code means: your boiler has lost communication with a sensor that monitors the temperature of the exhaust gases, causing it to shut down for safety reasons.. It appears on 5 Johnson Starley models 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: Flue gas temperature sensor open circuit, Temperature sensor not connected or failed
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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Johnson Starley models that show the 46 fault code

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

Source

Johnson Starley 46 fault code information on this page is sourced and cross-checked against the official Johnson Starley service / installation manuals for each affected model.

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