How much does it cost to fix Johnson Starley error code OVERHEAT?

Typical repair cost for the Johnson Starley OVERHEAT fault is £90-280 including labour.

OVERHEAT High

Johnson Starley OVERHEAT Fault Code

Q: What does the Johnson Starley OVERHEAT fault code mean?

Your boiler has become too hot and has automatically shut down to prevent damage to the internal components.

The Johnson Starley OVERHEAT fault code means: your boiler has become too hot and has automatically shut down to prevent damage to the internal components.. It appears on 1 Johnson Starley model in our database.

Technical description: Appliance requires cooling down. Includes checks for overheat sensor, service valve positions, water levels, and air in the system.

Typical repair cost £90-280 (including labour)

DIY fix possible

Ensure all radiator valves are fully open and not turned off.Check that your system water pressure is at the correct level (usually 1.0 to 1.5 bar).Bleed your radiators to remove any trapped air that might be blocking water flow.

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Johnson Starley models that show the OVERHEAT fault code

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

Warmcair DW Repair: £90-280

Source

Johnson Starley OVERHEAT 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