The most basic thermostat has 2 wires; usually a red and a white wire. Two wire thermostat wiring is used for furnaces only and usually doesnt need a “C” or “Common” wire. Thats why we only need two wires: Red wire for power (24h).

What are the 7 thermostat wires?

Thermostat Color Code R, Rc and Rh are red power wires. A blue or black wire is usually marked C, while the a white wire is likely marked W. The wire marked E is likely a brown one, and Y and Y2 are usually yellow. A wire marked G is typically green, while O is orange and B is blue.

What is a 2 wire thermostat?

If we put it simply, a 2 wire thermostat is one which has only 2 wires coming out of its backside. When it comes to low voltage systems, a 2 wire thermostat is usually known as a “heat only thermostat” and is used for systems like a gas furnace (with only heating option).