What color wire goes to C on a thermostat?
Blue wires
Blue wires are also called “C” wires because they are the Common wire. C wires are necessary for any “smart” thermostat that needs to be connected to a power source 24/7, regardless of your heat pump type.
What are the S1 and S2 terminals for on a thermostat?
S, S1, S2: These wires run directly outside and provide outdoor temperature information to the thermostat.
What is the difference between RC and RH on a thermostat?
There is no standard for the colour of the RH wire, but most units use a red one. The RC wire, on the other hand, refers to “red cooling”. It’s the same with the RH wire in that it powers the thermostat. For the RC, it powers the cooling system.
Do I need both RC and RH?
If you have both an Rh (Red-heat for powering the heating) and an Rc (Red-cool for powering the cooling), then the R wire can be connected to either Rh or Rc. If you only have a single R wire, then it will only have an R connector, which is the connection you’ll use.
Do I need a jumper between RH and RC?
Instead of using jumper wires, Nest Learning Thermostats use an internal jumper between the Rh and Rc connectors. A Nest Learning Thermostat will automatically use this internal jumper if your system needs it. Important: Never put more than one wire into a Nest thermostat connector.
What are the two wires on a thermostat?
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 doesn’t need a “C” or “Common” wire. That’s why we only need two wires: Red wire for power (24h). White wire for heating.
What is the Red Wire on a thermostat?
Red wire or “R” wire is the power wire. They originate in the transformer (air conditioners; in the air handler) and provide the 24-hour volt AC power. All air conditioner thermostats have a red wire for power. You may also have Rc or Rh terminals for dual transformer systems; these are special cases in thermostat wiring.
Where is the C wire on a smart thermostat?
More often than not, the black or blue wire connected to the C terminal is found in the newer “smart” thermostats. The older thermostats may not have the “C” wire; they function on-demand while the new ones function all the time (continuously 24/7).