Thermostat makes loud clicking noises frequently, disturbing occupants

Safety first: No need to open the thermostat for settings changes.

Steps to troubleshoot:

• Increase the temperature differential/hysteresis in the thermostat settings to reduce switching frequency.
• Change control mode from PWM to simple on/off if recommended for your heating system.
• Consider replacing the thermostat with a Tuya model that uses a solid-state relay (triac) for silent operation, especially for underfloor heating.
• If clicking becomes irregular or accompanied by heating failures, the relay may be failing and the thermostat should be replaced.