How can i figure out which wires go where, if the colors at the furnace don’t match the thermostat?

What color wires go where on a furnace?

This is the most typical thermostat wiring style, and it applies to systems that regulate both heat and air conditioning. The wires are typically arranged as follows: red for 24-volt hot, white for heat, yellow for cooling, green for the fan, and blue for common (although the common wire may be a different color).

How do you identify thermostat wires?

Look for connectors that have labels that are the same as your thermostat. For instance, you might find labels like R, W, G, Y, C or O/B. You should find wires attached to these connectors that are the same color as the wires that connect to your thermostat.

What happens if you wire a thermostat wrong?

Potential consequences of improper installation could include: Electric shock. Blowing a circuit breaker. Damaging the thermostat unit, the electrical system or even the AC/furnace unit itself.

How do I know if my wire is O or B?

Check the configuration. The heat pump is ‘O’ if it energizes in cooling and ‘B’ if it energizes on heating. Thermostats use the B terminal in systems with a reversing valve that turns on with heat mode. The system uses the O terminal if the reversing valve turns on while running cooling mode.

What color wires go together?

See Table below. The protective ground is green or green with yellow stripe. The neutral is white, the hot (live or active) single phase wires are black , and red in the case of a second active.



US AC power circuit wiring color codes.

How do you read a furnace wiring diagram?

Quote from the video:
Quote from Youtube video: So the connection diagram on this side is used to just basically find the components okay and then and then also trace the wires.

What color is the common wire 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.

Does red wire go to RC or RH?

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.

Where does blue wire go on thermostat?

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

What color wire goes in o B?

Dark Blue Wire

Dark Blue Wire For B (O/B)



When it comes to the dark blue wire, it can reverse valve heating. Some models require a dark blue or B-wire for the t-stat terminal when the heating mode is on. Keep in mind that the dark blue wire and the orange wire are interchangeable.

Is my heat pump O or B?

On many other thermostats, the O wire is typically connected to a terminal marked W on one side and O or O/B on the other side; the W is for use with a conventional system (furnace) while O/B is for use with a heat pump.

What is the OB wire?

O, B, O/B: These wires are responsible for switching the changeover valve in a heat pump system. The O wire reverses the valve from heating to cooling, and the B wire switches the valve from cooling to heating. Sometimes it might be a single O/B wire instead of two separate wires.

How do you wire a furnace thermostat?

Quote from the video:
Quote from Youtube video: Inside the furnace you see that we have a W and R a Y a G and a C and so those are located on the control board inside the furnace the terminals for the thermostat or W. That's for heat Y.

What is the Y wire on a furnace?

Y – This is the terminal for cooling or air conditioning and goes to the compressor relay. Typically a thermostat wire pull is made to the air handler on split systems and then this wire is spliced for the separate wire pull which is made to the condenser.

What does W1 and W2 mean on a thermostat?

W/W1 and W2. In a conventional system, W/W1 controls your heating system and, where applicable, W2 controls your heating system’s second stage, which helps warm the home faster.

Can you jump W1 and W2 on thermostat?

If W1 is only wired up, it will always run in 1st stage, 2nd won’t come on unless W2 is wired to a two stage t-stat, or jumper to it.

Does white wire go to W1 or W2?

Thermostat White Wire (“W1” or “W2” Wire)



W wires go directly to the source of heating; that may be a furnace (gas, electric, oil, you name it) or heat pumps (mini-split heat pumps included). W2 is designated for two-stage heating. Most heat pumps include second-stage heating and require the white W2 wire.

What color is W2 wire on thermostat?

General Thermostat Wiring Color Code

Are R and RH wires the same?

R , Rh , and Rc are all the same, but not. In general terms, the R terminal is where you connect the signal voltage source. In low voltage controlled systems, there will be a step down transformer that provides the power to the control circuitry.

What letter is the black wire on a thermostat?

C