Thermostat emits a burning smell or feels unusually hot to the touch.

Immediate safety warning: If you smell burning or the thermostat is very hot, turn off power to the HVAC system at the breaker immediately.

Steps:

• Do not continue using: Remove the thermostat from the wall after power is off and allow it to cool.
• Inspect wiring: Check for signs of melted insulation or miswiring (e.g., line voltage wires connected to low-voltage terminals).
• Do not attempt repair: A thermostat with internal burning damage must be replaced, not repaired.
• Have wiring inspected: Before installing a new thermostat, have a qualified technician verify that the low-voltage wiring and transformer are correctly configured and not supplying excessive voltage.