![Old thermostat has only these three wires. How do I hook up a Sensi Smart Thermostat? : r/electrical Old thermostat has only these three wires. How do I hook up a Sensi Smart Thermostat? : r/electrical](https://i.redd.it/old-thermostat-has-only-these-three-wires-how-do-i-hook-up-v0-ij8f74hihda81.jpg?width=3024&format=pjpg&auto=webp&s=863a25bc5c6dd3129f9f09546f0d3172e06f2eb7)
Old thermostat has only these three wires. How do I hook up a Sensi Smart Thermostat? : r/electrical
![Amazon.com: Refrigerator Bimetal Defrost Thermostat by AquaMonica Fridge Freezer Defrost Temperature Control Switch (-5℃ Three-Wire (Square)) : Appliances Amazon.com: Refrigerator Bimetal Defrost Thermostat by AquaMonica Fridge Freezer Defrost Temperature Control Switch (-5℃ Three-Wire (Square)) : Appliances](https://m.media-amazon.com/images/I/71LcHqgy0CL._AC_UF894,1000_QL80_.jpg)
Amazon.com: Refrigerator Bimetal Defrost Thermostat by AquaMonica Fridge Freezer Defrost Temperature Control Switch (-5℃ Three-Wire (Square)) : Appliances
![wiring - How to figure out how to wire a 2 wire furnace to 3 wire thermostat - Home Improvement Stack Exchange wiring - How to figure out how to wire a 2 wire furnace to 3 wire thermostat - Home Improvement Stack Exchange](https://i.stack.imgur.com/2GD2h.jpg)
wiring - How to figure out how to wire a 2 wire furnace to 3 wire thermostat - Home Improvement Stack Exchange
![Current thermostat has W, B and R wires. Not sure which one is common. We only have a boiler heater no cooling. : r/Nest Current thermostat has W, B and R wires. Not sure which one is common. We only have a boiler heater no cooling. : r/Nest](https://inspectapedia.com/heat/TT_T87F_0002_3W2_DJF.jpg)