Is C wire required for Nest?

With a Nest Thermostat E or Nest Learning Thermostat, you’ll need to install a C wire if the thermostat has power issues or its battery often drains.

What happens if Nest doesn’t have C wire?





In a system with a C-wire, the Nest charges itself from the C-wire’s current and all is fine. In a system without a C-wire, though, Nest recharges its battery when the heating or cooling runs. It diverts a little bit of the power to itself and charges its own battery.

Where is the C wire on a Goodman furnace?

Quote from the video:
Quote from Youtube video: The wire coming from outside from the condenser unit is only going to have two wires a red and a white looking like this. And those two are going to go to y. And c common on that terminal strip.

How do I connect Nest without C wire?

Quote from the video:
Quote from Youtube video: For the common wire. So what you would do is go to your nest thermostat. Take off the G wire. Usually. It's going to be the green wire going to G. So you press on it you pull it out and before.

Can you use G wire for C wire?

If there is no hidden C-wire, you can use a G-wire instead. However, you will not be able to use your fan independently when the heating or cooling isn’t running. Also, many HVAC systems are incompatible with this solution, including: HVAC systems using electric heat.

Do all Wi-Fi thermostats require C wire?





The good news is, some of the best smart thermostats do not require the power from the C wire to work. In fact, some of the best smart thermostats like the Google Nest Thermostat have no requirement for the C wire as they contain rechargeable batteries or other technology that removes the need for one.

How do I bypass the C wire on my thermostat?

Quote from the video:
Quote from Youtube video: Connect the extra wire to the C terminal of Union thermostat trace the extra unused wire from the thermostat to the furnace board make sure it's connected to the C.

How do I connect the common wire to my Nest Thermostat?

Quote from the video:
Quote from Youtube video: So here in my old wiring you can see that i have the y1. Gw1 rh and the c-space is missing that c wire. So here i definitely could use the c wire now that we have determined we need to add the c wire.

Can I use a Nest thermostat with only 2 wires?

The Nest Thermostat is compatible with 2 wire low voltage HVAC systems that are either heat only systems or cooling only systems.

What color is the C wire?



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.

How do I know if C wire is live?

Quote from the video:
Quote from Youtube video: Begin by putting one probe whichever probe you want on the rh wire and test every other wire with the other probe. One of the wires will show up is 24 volts and that is your c wire.

Why is Nest not compatible with stranded wires?



Your Nest thermostat might not sense your wiring if the wires for your heating and cooling system are too thin. Nest thermostats require wires between 18 and 22 gauge, which is standard for residential heating and cooling systems. Anything smaller than 22-gauge wire could be too thin for a Nest thermostat to detect.

Does Nest Thermostat E work without C wire?

Nest claims that you can use the Nest Thermostat without a C-wire. While this is true, it would be advisable to have a C-wire. A lot of Nest users have had problems when they use the thermostat without a C-wire. In the absence of a C wire, your thermostat battery charges itself by using the power from your HVAC system.

What wires work with Nest?

Nest thermostats can work with systems that use Service Light (L) wires. While L wires can’t be connected to the Nest thermostat, it doesn’t need them.

What is the C wire on a thermostat?

C-wire is an abbreviation for “common wire,” although it is not so common as you may expect. By closing the circuit, it delivers constant 24-volt power to your thermostat.

Is RC the same as C wire?



No the Rc is the red wire. You need 5 wires or more for this to run with all the functions. You can use one of the other wires but you have to drop control of the fan. It will only come on when furnace comes on.

Is com 24v the same as C wire?

Thanks! Yes, it’s the same. “Common” or Com or C is a commonly used term for the neutral conductor in low voltage AC circuits.