BoilerFaultCodesJohnson Starley NO DISPLAY Fault Code
Also written as NODISPLAY — same fault.
The Johnson Starley NO DISPLAY fault code means: your boiler has lost power entirely, which is usually caused by a tripped switch at the fuse box or a fault with the electrical supply to the unit.. It appears on 2 Johnson Starley models in our database.
Technical description: Lack of 230V AC supply to heater or loose wiring between terminal block and main PCB.
DIY fix possible
Check your home's main consumer unit (fuse box) to see if any circuit breakers have tripped.Ensure the boiler's fused spur switch (usually a switch near the boiler) is turned on.Check the fuse inside the boiler's external switch if you are comfortable doing so.
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Gas Safe Register →Johnson Starley models that show the NO DISPLAY fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Johnson Starley NO DISPLAY 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 27 April 2026