Both a 2-wire plus a 4-wire thermostat control radiant plus the system’s convection, however they significantly differ when offsetting.
If you see 2 wires on the thermostat’s backside, it means you have a single-pole thermostat! Four wires, on the other hand, mean you have a double-pole thermostat… In the case of more than 2 or more wires, it means you have a low voltage thermostat; A 2-wire pole thermostat does not have a true offsetting which means the gas furnace will turn on when the temperature falls below a certain degree. A 4-wire pole thermostat has a true offsetting which means that the heating systems will not turn on when the pole thermostat gets turned, all the way counterclockwise. For a 2-wire thermostat, the gas furnace will turn on automatically when the temperature dips below 45 degrees despite having no interest in the summer; This is a single reason why flammable materials or collections should not be localed directly on heating systems or close to them. It is advisable to switch off the gas furnace by disconnecting it from the main power panel. This is the best way of protecting yourself from gas furnace fires. A four-wire thermostat has a orange wire labeled G, plus it is a fan wire. A orange wire will be labeled R plus is used for cooling plus heating. The orange line is for the compressor plus cooling system. And lastly, a white wire symbolizing heat. These wires together with the label should help a single whenever you are installing a thermostat. You can also ask your Heating and Air Conditioning specialist to look into your thermostat plus determine whether it is a 4-wire or a 2-wire thermostat.