Where does blue wire go on nest?

Asked By: Betty Chrifi | Last Updated: 1st March, 2020
Category: home and garden smart home
4.9/5 (194 Views . 19 Votes)
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.

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Similarly, what is the blue wire on a thermostat?

The blue wire, or C-wire, is known as the common wire. It's there to provide power to the thermostat. Older thermostats usually don't have a C-wire because they either don't need power or, if they do, they get it from a battery.

Similarly, where does the C wire connect on furnace? Since that wire is clearly Y, the other wire in the cable going to the condenser (the white wire, since it's a two-wire cable) must be your C wire, and you can connect the blue wire in the thermostat cable there (after turning the power to the furnace off and stripping the wire end back, of course).

In this regard, does Nest require C wire?

In most cases, a Nest Thermostat can work without a common wire. Without a common wire it charges its internal battery using power from the heating and cooling wires. With some HVAC systems, such as micro-controller-based systems and certain gas valves, will require a C-wire to work with Nest Learning Thermostat.

What does a blue wire mean?

Blue and yellow Yellow and blue electrical wires are also used to carry power but are not for wiring the outlets for common plug-in electrical devices. These colors are used for the live wire pulled through conduit. You'll use blue mainly as a traveler for a three-way or four-way switch.

27 Related Question Answers Found

Is the blue wire the C wire?

There are no standards for wire color!
Here are common uses for wire colors: Blue or Black – C – Common wire, may be unused by your existing thermostat. Enables continuous power flow from the Red wire. Red – R – 24VAC power from the furnace's transformer.

Is RC the same as C wire?

Though it is a common notion, it may be incorrect to state that the C-wire powers the thermostat. Typically, the wires that give the power supply (usually termed as the 'hot' wires) are marked Rc (for cooling) and Rh (for heating). They give a 24-volt power supply from the HVAC system's control panel.

What color is the common wire?

The "common" is the "neutral" or "ground" wire, depending on the type of circuit. In normal US residential wiring, you'll have a black "hot" wire, a white "neutral" or "common" wire, and a green or bare "ground" wire.

What color is AC wire?

Y wire (yellow, for air conditioning). W wire (white, for heat). C wire (blue or black, common for 24-volt power to the thermostat).

How do I install a WIFI thermostat without C wire?

To add a C-wire to your furnace, follow these steps:
  1. Turn off the breaker for the furnace.
  2. Remove the access panel and locate the wires that connect to the thermostat.
  3. Disconnect the thermostat wire from the G terminal.
  4. Note: If you have both central heat and air, then you'll need to make a jumper using an 18 AWG wire.

What do the different color thermostat wires mean?

The white wire is usually connected to the “W” terminal. The thermostat acts like a switch, like a light switch. The Red to white switch turns on the heat. Red to Green turns on the fan, Red to Yellow turns on the air conditioner.

How many wires does a thermostat need?

In the most basic system, this functionality is provided by use of a fan center relay, and the low voltage wiring to the thermostat now will require a minimum of three wires (for heat only units) and four wires (for heat / cool / fan) for control.

Do I need to charge my Nest thermostat before installing?

The Nest thermostat keeps its internal battery charged using your heating and cooling system wires, but if there's a problem the battery may drain. Usually your thermostat will take about half an hour to recharge. But if the battery is fully drained it can take as long as two hours to recharge.

What is C wire required?

A common wire (C-Wire) provides Wi-Fi thermostats continuous power by connecting it to a heating and cooling system (e.g. furnace). C-Wires are required on most Honeywell Wi-Fi thermostats, with the exception of the Smart Round Thermostat (formerly known as the Lyric Round).

How do I know if I have C wire?

It is easy to see if you already have a c-wire connected to your system. Simply remove your current thermostat face from its baseplate and look for the terminal labeled with the letter “c.” If this terminal has a wire attached to it, you have an active “c-wire.”

Will a Nest thermostat work with two wires?

Nest thermostats can work with systems that use Service Light (L) wires. While L wires can't be connected to the Nest thermostat, they don't need them. The Nest thermostat and Nest app will show you system status information without connecting L wires.

How much does it cost to install c wire?

If you need a C wire run, expect the installation costs to be roughly double, at $170 to $200 for the job. Including the cost of a new thermostat and installation, the total cost is around $300 on average.

How many wires can be connected to the C terminal at the furnace?

Technically, there should only be one wire connected to the screw terminal. However, it's common practice in the HVAC industry to connect more. If you want to do it the proper way, you should use a twist-on wire connector (or other connector), and a length of scrap wire to make a pigtail.

How do you wire a C wire to a furnace?

Start by removing the access panel on the furnace, and locating the thermostat wires. Remove the wire from the G terminal, and connect it to the C terminal. Using a short piece of 18 AWG wire, make a jumper and connect it between the Y and G terminals (this is only required if you have both heat and central air).

What is the difference between nest and nest E?

The major difference you need to know is that the Nest E doesn't support Nest's Farsight tech. It's the feature that can sense you walking in the door, will wake up the thermostat, and can override any energy-saving settings you might have programmed for the times you're not home.

What is common wire?

A common wire is a more general term and simply refers to the 0 Volt wire of a circuit, either electrical or electronic.