Thermostat emits buzzing or humming noise when calling for heat

Safety first: Isolate power before touching the thermostat or receiver.

Steps:

• 1. Identify source: Place your ear near the thermostat and RF receiver to determine which unit is buzzing.
• 2. Tighten mounting: Ensure the receiver is firmly fixed to the wall and not resonating against a hollow surface.
• 3. Check supply voltage: Measure voltage at the receiver; low voltage can cause relay chatter. Correct any supply issues.
• 4. Replace noisy component: If the relay itself is buzzing and the unit is old, replace the RF receiver or thermostat.