BoilerFaultCodesJohnson Starley 43 Fault Code
The Johnson Starley 43 fault code means: your boiler has detected an electrical fault with the internal sensor that monitors the temperature of the air returning to the unit, causing it to shut down for safety.. It appears on 4 Johnson Starley models in our database.
Technical description: Return air temperature short circuit. Temperature sensor shorted to. Check wiring connections not shorting to earth. Check sensor resistance.
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 43 fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Johnson Starley 43 fault code information on this page is sourced and cross-checked against the official Johnson Starley service / installation manuals for each affected model.
- Johnson Starley C10d manual (PDF)
- Johnson Starley C16d manual (PDF)
- Johnson Starley C16u manual (PDF)
Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 7 July 2026