Thermostat makes clicking or buzzing noises when turning the heater on or off.

Safety first: Turn OFF power at the breaker before removing the thermostat if you need to inspect it.

Steps to evaluate:

• Determine noise type: A single soft click at on/off is normal. Loud, repeated clicking or buzzing is not.
• Check load type: Ensure the connected heater is a resistive load and not an inductive motor or fan that can cause relay chatter.
• Inspect mounting: Make sure the thermostat is firmly mounted to the wall plate and the wall box is secure; vibration can amplify normal sounds.

Persistent loud buzzing or rapid clicking usually indicates a failing relay or incompatible load. Replace the thermostat and verify the heater type is supported.