How to Fix / Troubleshooting

Safety first: No high-voltage work is needed for configuration changes.

Steps to troubleshoot:

In the thermostat installer settings, adjust the control algorithm (e.g., change from on/off to PWM or adjust cycle rate) according to the heating type (radiator vs underfloor).
Enable and correctly configure the floor sensor for underfloor heating to limit floor temperature and reduce overshoot.
Relocate the thermostat away from direct sunlight, radiators, or drafts that can mislead the sensor.
Reset any temperature offset to 0 and recalibrate by comparing with a reliable thermometer.
If overshoot persists despite correct settings and location, the internal sensor may be inaccurate; replace the thermostat.

Thermostat overshoots set temperature significantly; room becomes too hot before heating turns off

Possible Causes