- Turn off the power to the air handler at the breaker box.
- Pull the top of the thermostat off the wall.
- Remove and label each wire attached to the bottom plate. Label wires according the code on the terminal from which it was removed.
- Remove the bottom plate completely. Mount the new bottom plate.
- Connect the wires according to the labels on the bottom plate. For example: Y for yellow wire, W for white wire, R for red wire and G for green wire.
- Snap on the thermostat to the bottom plate.
How to Wire a Trane Baystat 305
Thermostats regulate the air in your home or office. Modern thermostats provide many more options than thermostats from a few years ago. Some consumers are not ready to welcome the technological advances thermostats have to offer, says Alan Boleware, an air-conditioning service technician in Indian Harbour Beach, Fla. Boleware says many of his older clients prefer the simple nondigital thermostats like the Trane Baystat 305. The Trane Baystat 305 is made simple with only four wires to connect.