An extra unused wire in the wall can be used as the C wire for your new thermostat. The extra wire will also need to be connected to the C (common) terminal at the heating and cooling system. This will provide power to your new thermostat.
Why does my thermostat have 6 wires?
If your system has six wires, it’s because it features second-stage heating, second-stage cooling or heat-pump cooling but not all three. The extra wire signals the additional function to come on. If your system has second-stage heating and cooling as well as a heat pump, then the thermostat needs eight wires, not six.
Why do I have two thermostat wires?
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).
Why does my thermostat have 4 wires?
The concept is that when you adjust your thermostat its like flipping a switch, and you are providing power to the your HVAC system to work, it’s just that in a typical 4 wire thermostat the thermostat decides where to route the power to turn on your HVAC system to make it heat, cool or run the fan.
Why do thermostats have 3 wires?
Some older thermostats do indeed have three connections: 2 for switching and one (neutral feed)to power a heating resistor to act as an “anticipator”. However if you are using two 2-port motorised valves, then you need the third wire to isolate the valves from each other.
What is the B wire on a thermostat?
The O wire reverses the valve from heating to cooling, and the B wire switches the valve from cooling to heating.
How many wires does a thermostat need?
Most systems today require a minimum of 5 wires when both heating and air conditioning equipment is included in the system. Our pro recommendation is to use 18/8 wire.
How do you wire a 4 wire to a 2 wire?
The first option is to use the black wire of the 12-3 cable as the hot wire. Connect the black wires of both cables together, and connect the common white wires together. Cap the red wire and leave it untouched in the junction box. Place plastic twist caps on all splices.
How do I install Honeywell thermostat with 3 wires?
Quote from the video:
Quote from Youtube video: To do this connect all wires to their designated letter terminals at your wall plate except the wire labeled g. Instead insert the g wire into the c terminal on your wall. Plate.
What is the green wire on a thermostat?
The green wire underneath your thermostat connects to the fan of your furnace or air handler. It terminates at the air handler or furnace. The green wire connects to terminal G on your thermostat.
Is G wire necessary?
As you mentioned, you don’t usually need a G wire for heating mode, but you do for cooling. In special circumstances a relay could be wired up inside of the air handler to make the fan come on with a call for cooling, but normally it’s the thermostat that makes the connection that makes the fan come in in cooling mode.
What is the blue wire on thermostat?
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 do the colored wires mean on a thermostat?
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).
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.
What is the GREY wire on a thermostat?
Other Wire Colors: Gray wire: may be Aux emergency heat, mayu connect to E. The temperature actuated on off switch in a thermostat is actually a single pole double throw switch which will have either the heating or the cooling side closed at all times.
