Safety thermostat (overheat) High

Grant Safety thermostat (overheat) Fault Code

Also written as SAFETYTHERMOSTATOVERHEAT — same fault.

The Grant Safety thermostat (overheat) fault code means: your boiler has detected that it is running too hot and has automatically shut down to prevent damage or dangerous overheating.. It appears on 1 Grant 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: Automatically switches off the boiler in the case of a control malfunction causing overheating.
Typical repair cost £120-250 (including labour)

Engineer required

This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.

Find a Gas Safe engineer

Search the official register for a qualified engineer in your area.

Gas Safe Register →

Grant models that show the Safety thermostat (overheat) fault code

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

Source

Grant Safety thermostat (overheat) 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