Thermostat emits a buzzing or humming noise when calling for heat

Safety: Turn off power at the breaker before removing the thermostat or opening any covers.

Steps to reduce buzzing:

• 1. Confirm source: Place your ear near the thermostat and then near the heater to determine where the noise originates.
• 2. Tighten mounting: Ensure the thermostat is firmly mounted to the wall plate and that the wall plate is securely attached to the electrical box.
• 3. Check wiring: With power OFF, verify that all wires are tightly secured and not vibrating against the thermostat housing.
• 4. Inspect heater: Some Stelpro heaters can buzz if elements are slightly loose. Tighten accessible mounting screws on the heater (power OFF).
• 5. Replace thermostat: If the noise clearly comes from the thermostat relay or triac and is loud or worsening, replace the thermostat.

Note: A faint click or very light hum is normal; loud or new noises warrant investigation.