TP-Link Kasa Relay Chatter or Electrical Noise

Thermostat emits buzzing or clicking noises frequently

This repair may involve working with high voltage components or water connections. Always unplug the appliance before removing any panels.

If you are not confident in your ability to perform this repair safely, we strongly recommend contacting a professional technician.

Possible Causes

Unstable 24V supply, Loose low-voltage connections, Failing relay on thermostat, Electrical interference from nearby equipment

Safety: Turn off HVAC power before tightening wiring.

Tighten wiring: At thermostat and furnace board, tighten all low-voltage terminal screws.
Check transformer: Have a technician verify the 24V transformer output is stable and not dropping under load.
Relocate wiring: Keep thermostat cable away from high-voltage lines or motors that can induce noise.
Replace thermostat: If buzzing persists and is localized to the thermostat, the internal relay may be failing and the thermostat should be replaced.

Medium 3/5

Thermostat Relay Module / 24V Transformer

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