Blue wires are for heat pumps, like orange wires. This wire connects to terminal B on your thermostat.

What is the blue wire in thermostat wiring?

The Rh wire connects to the heating system. This wire may be red without an “H” attached, in some cases. Blue. The blue wire on the thermostat is the Common or “C” wire.

Where does the blue wire go on a 4 wire thermostat?

4 Wire Thermostat Wiring Color CodeRed Wire = Rh = Power.White Wire = W = Heating Wire.Yellow Wire = Y = Cooling Wire.Green Wire = G = Fan Wire.Blue Wire = Y = Cooling.12 Jun 2019

Why does my thermostat have a blue wire?

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. Blue wires are for heat pumps, like orange wires. This wire connects to terminal B on your thermostat.

Where does blue wire go in nest?

If your thermostat doesnt have a separate connector labeled C and youre not sure what type of system you have: A brown wire is mostly likely a heat pump wire and should be connected to the O/B connector on the Nest thermostat. If the B wire is blue, it should most likely be connected to the C connector.

Where does the blue wire go on a thermostat?

C wires or varying colors apply to every thermostat, but blue C wires belong to thermostats attached to a heat pump. Blue wires are for heat pumps, like orange wires. This wire connects to terminal B on your thermostat.

Do blue and black wires go together?

The black and blue wires need to be connected. You will be able to control your fan and lights with a single switch. You should twist the black and blue wires the same way you did the previous wires.