OVERHEAT HIGH LIMIT High

Johnson Starley OVERHEAT HIGH LIMIT Fault Code

Also written as OVERHEATHIGHLIMIT — same fault.

The Johnson Starley OVERHEAT HIGH LIMIT fault code means: your boiler has switched itself off because it has become too hot and needs time to cool down safely.. It appears on 1 Johnson Starley 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: Heater has exceeded temperature limits. Requires wait for pump over-run and cooling before reset. Includes checks for overheat limit switch continuity, PCB replacement, pump/valve operation, and strainer/filter clarity.
Typical repair cost £120-350 (including labour)

DIY fix possible

Turn the boiler power off and wait at least 30 minutes for the unit to cool down.Check that all radiator valves are fully open and there are no blockages in the air grilles.Press the manual reset button on the control panel once the system is cool.

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Johnson Starley models that show the OVERHEAT HIGH LIMIT fault code

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

Source

Johnson Starley OVERHEAT HIGH LIMIT 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