How much does it cost to fix Grant error code Safety thermostat?

Typical repair cost for the Grant Safety thermostat fault is £90-180 including labour.

Safety thermostat High

Grant Safety thermostat Fault Code

Q: What does the Grant Safety thermostat fault code mean?

Your boiler has switched itself off because its internal temperature has become too hot, triggered by a safety sensor to protect the system.

Also written as SAFETYTHERMOSTAT — same fault.

The Grant Safety thermostat fault code means: your boiler has switched itself off because its internal temperature has become too hot, triggered by a safety sensor to protect the system.. It appears on 1 Grant model in our database.

Technical description: Your boiler is fitted with a safety overheat thermostat which will automatically switch off the boiler in the case of a control malfunction causing overheating.

Typical repair cost £90-180 (including labour)

DIY fix possible

Locate the high-limit thermostat reset button, which is usually found behind the front casing or under a small plastic screw cap.Press the button firmly once to reset the safety switch.Check that your radiator valves are open and that the system pressure is between 1.0 and 1.5 bar.

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Grant models that show the Safety thermostat fault code

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

Vortex Blue / Vortex Outdoor Repair: £90-180

Source

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

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 27 April 2026