I Figured It Out! The C Wire! Nest Thermostat

[@ricanrolla85]

Common wire is just to keep your thermostat charged. Your thermostat will work perfectly without it, you’ll just need to charge every other month or so.

[@ShoresLife]

That was the case at our old apartment which had no C wire. I'm not sure what was up with our current one in the home we're renting now, but it would not kick on the cold air until the C wire was connected. It's been a year and everything has been working great, even in this 106 degree heat!

[@threestans9096]

@@ShoresLifeyeah ive heard on the internet ones, they need the C. its caused lots of headaches for techs i guess.

[@mandyhaven4290]

A lot of hvac professionals are advising not to use nest . My hvac guy was out today . We put in nest thermostat 2 weeks ago no c wire . I was hearing like a clicking noise after while was running and it also sounded as if fan was losing power at times . Anyways our control board went out coincidence idk but there are a lot of claims that nest is breaking furnaces especially when you run without c and do there work around to steal power

[@sot8343]

​​@@mandyhaven4290yeah our nest has fresh batteries and functions most of the time but it's always acting up and throwing warnings about power issues. Sucks when it goes offline. Definitely not satisfied with Nest.

[@The-adventurer112]

Clearly install a c wire and it would fix the problems…

[@empirre6]

Thank you so much you don’t know how much you helped me cause other videos they didn’t even have a blue wire

[@Hvacr123]

Did u guys strip them wire with teeth?

[@ShoresLife]

Ha, maybe the previous homeowners did!

[@deenyc1049]

I have 2 nests and no C wire and they've been working for 3 years now. I ran into an issue once where the power died, I manually charged it for 30 minutes and it hasn't given me trouble again.

[@brianmahoney154]

You need a hot wire and neutral to run something. That’s using batteries in most thermostats. But you need more power to run this thermostat so instead of using two 1.5 DC volt batteries you use the R for hot and the C for your neutral to power the thermostat. If you didn’t want the set back features you wouldn’t need any power. Old thermostats used mercury switches. Now they use bi-metals.

[@Zee20Ate]

A lot of wrong info in the comments. A c-wire is NOT required for a nest thermostat. Exactly the reason o went with the nest because I didn’t have one. It operates properly and has never lost charge. You can check online to see if your current wiring setup is compatible.

[@electricianron_New_Jersey]

I think you have the wrong info. The C wire should be hooked up to the common terminal at the furnace/ air handler.

[@Zee20Ate]

Still no issue with power. It’s been installed over a year now.

[@garzdiva]

When there's no C wire, the Nest leeches power off Cooling or Heating when they kick on to recharge its battery. Sometimes it causes issues sometimes it doesn't. It's just up to luck if your system will be stable running without the C wire.

[@koriwest]

If you have a c-wire you should connect the c-wire. If you do NOT have a c-wire the Nest is supposed to work without it, but you will eventually get error codes for it not getting enough power to run all its spyware. So then you either have to pay to have a c-wire installed or buy and install their power adapter. Google really shouldn’t be selling this to people who don’t have a c-wire.

[@Zee20Ate]

@@koriwest still working. Years now with no errors. No real problems. I did have to charge it once this spring when I didn’t need heat or a/c for a long time. After that one charge with usb cable I haven’t touched it since.

[@dieselstar5]

How’s the heat working?

[@ShoresLife]

Working good, thankfully! It’s 20 degrees tonight in San Antonio!

[@johny1220]

Getting my Nest in tomorrow, I saw an unused C wire as well, will definitely connect it with the nest. Thanks! 😄

[@ShoresLife]

no problem! glad i could help!

[@Dachamp2001]

C is common Y1 is for basic AC. Y2 is for 2 stage cooling. C basically completes the circuit so it keeps your thermostat charged & if you wanna add like a humidifier.

[@ShoresLife]

awesome, appreciate that extra info! That explains why our thermostat would die during the winter at our old apartment. We had no C wire there, so I believe it only charged when the unit was on.

[@Dachamp2001]

@@ShoresLife W/O the C wire the thermostat will not charge regardless if the AC or furnace is running. You would have to manually charge the batteries or replace them. 😉 The thermostat is a relay it will bridge the R wire with Y1 for AC or W1 for heat. The hvac system has its own ground except the thermostat when the C wire isn't connected.

[@Andrew-w2p]

So I'm putting in a new thermostat, nothing fancy. the old one has a blue wire but not connected. Im just trying to figure out if I should hook it up when I put the new one on?

[@ShoresLife]

@@Andrew-w2p from what I've read, the blue wire is not always the C wire. I found out mine was after looking up the model number of our inside AC unit and finding that it did have a C wire connection, and then ruling out all the other wires. If it is a C wire, sometimes it won't be connected because the thermostat is battery operated (the C wire provides power to the thermostat). The thermostat that was connected at our place before I installed the Nest had 2 double A batteries which is why they didn't connect the C wire. I'm no professional, but if you can find the model number of the inside unit, that'd be your best bet to see what wire connections it has.

[@calebsonger4552]

What is stage 2 cooling?

[@miguelpadilla9188]

No c wire will ruin your furnace if an hvac tech and idk but these nest go crazy out of nowhere and cause crazy behavior on the system because it starts to pull power from anywhere in your furnace board

[@seangilbert19658]

Thanks for the explanation guys, because I’m looking on buying the third generation Google nest, and mine does have the C wire. And I am going to connect it to the terminal. 👍

[@MMcAfro]

So,.....if there is no c-wire on the old wiring i suppose that you can just jam a length of blue wire in the wall and connect it to the c terminal? "Once I put that c-wire in there" 🙄

[@ShoresLife]

If the unit has a C wire connection to begin with, then I'd think so. What made me realize that the blue wire on mine was the C wire is I pulled out the manual taped to my unit and it specifically showed on a diagram where the C wire connection was (which had the blue wire connected to it)

[@dsantostv3711]

I spoke to an expert and he told me you don’t need a c wire on the nest thermostat ❤

[@dsantostv3711]

I have 2 nest thermostats and I’m not using a c wire. No problemas for 5 years ❤

[@ShoresLife]

Just to be clear, I’m using the c wire now at our place we’ve lived in for about a year, but our old apartment had no c wire. The worst that would happen was during the winter when the unit was barely used and our nest would run out of battery because it was only being charged with the R wire when the unit was on. I’d just pull the nest off and charge it with the micro-usb plug for a bit and it’d be fine.

[@werlder]

@@dsantostv3711this is not true. Heating-only systems specifically require a common wire.

[@coryemanuel176]

Exactly what I needed to know! My connector comes in today and hopefully will have everything back working before my wife leaves me.

[@ShoresLife]

🤞🏼it drove me crazy for a couple of days until I figured it out. Going strong for over a year now!

[@carinatu8634]

We just installed Nest Thermostat with R (red wire), O/B (white), Y(yellow), G (green), C (blue wires). Not sure why our ac compressor is turn on when heat is on. Please help.

[@ShoresLife]

Hey Carina, I'm not an expert by any means, but I think our outside compressor still kicks on occasionally with the heat one. Any experts out there, feel free to chime in!

[@lawnside82]

Thats called heat pump. When the temp outside is over 32 , hp licks in. Its the ac running backwards. When outside temp is under 32, emergency heat kicks in. That expensive heater coils heat up. Similar to a space heater. It works but uses a ton of electricity.

[@ShoresLife]

@@lawnside82 thanks for the explanation!

[@quintin993]

Common wire to the thermostat is to provide permanent power to the thermostat , it doesn’t affect the unit opperation. For people that are upgrading thermostat if your c wire is not hooked up and you do have an extra wire you just need to make sure inside the unit is conected to the c conections most of the time blue or brown low voltage wires, always turn the power off before doing anything ,you can easily blow a fuse or even damage the transformer

[@luiscruz-ui7uq]

Do these use batteries?

[@ShoresLife]

From what I understand they have a rechargeable battery that can be charged when your unit is running if you don’t have a c wire. If you have a c wire, then it receives constant power

[@jimeagle1155]

The C wire has absolutely nothing to do with the air conditioning, the air conditioning compressor is controlled by the Y wire in the blower motor is controlled by the G wire. The blue C wire is a generic common ground just there to let your thermostat power off of the Rh or Rc wire.

[@FutureAIDev2015]

I thought the official instruction video doesn't use the C wire...

[@radousa]

I have the 3rd gen and I don't have the C wire. Yellow wire to Y1 for A/C, green wire to G for fan, red wire to Rh for power and white wire to W1 for heat. A/C works without the C wire.

[@plainandsimple1]

Most people will jump the rh and rc wire as well behind the thermostat

[@SundownCamry]

​@@plainandsimple1I believe with the nest thermostat it's already jumped behind it.

[@devora455]

You definitely not need the C wire to use the nest thermostat. You might need to charge the thermostat every couple weeks maybe. That's how i use my nest thermostat.

[@jessiemadrid9543]

How long do you charge it for? Currently having this problem where ac turns in but shuts off right away

[@samlopezjr5533]

Same issue ​@@jessiemadrid9543

[@J-O-H-N]

Seems like if you have a wifi thermostat, they dont take batteries and require common but when the wifi option is removed, you have the battery option. Guess we can't have both at the same time...

[@christophertosado9961]

I have the same setup and kept getting an error. It said there was no power to the C wire... I disconnected the C wire, and now it's working fine. Any thoughts?

[@ShoresLife]

unfortunately, I'm not an expert on this, but hopefully someone with HVAC experience can chime in. It was weird for me because before I connected the C wire, it would turn on, but not get cold or blow out air with any force. As soon as I connected the C wire, everything just worked.

[@Fedali-h7o]

I need help. I think I have the C wire,I connected everything perfectly 👌, but I am still getting hot 🔥 🥵 air instead of cold. I removed it,installed the old one, the same way, and cold 🥶 air is working perfectly. What do I miss? Using the Amazon thermostat. Help

[@jimeagle1155]

You have to go to the furnace area and see how the wires are hooked up, just because the wire is the right color doesn't mean it's hooked up the right way, it sounds like your yellow wire and white wire are not connected properly at the furnace control board.

[@krisj2391]

Having the same issue now. No C wire and my AC won’t cut on

[@plightn]

What’s the orange wire for?

[@DJV94022]

If youre outside unit is a heat pump type meaning if its a carrier,lennox,trane,goodman etc etc once the thermostat passes 24 volts to orange wire it makes your unit go into cooling..if orange doesnt get 24v and the unit is running then its in heat mode and youll def feel the room heating up..all this is truth except for rheem and rue ..those brand come stuck in cooling out of the box. When you apply power to orange it goes into the heat

[@whyYoustalking]

That's the common wire. The red R wire is wire with the electricity . Common-wires are always needed

[@Mia-ht8oi]

We paid a technician to install this thermostat. After couple mins it stopped blowing cold air. He then blamed it on the board stating I need to change the board. Called google nest and they told me abt the C-wire, which obs we didnt have since previous one was battery operated. Might need to call another tech to take care of this. Was was the cost estimate for installing C wire?

[@ShoresLife]

ours already had a c wire installed and sticking out where the thermostat was, but it wasn't previously connected to the prior thermostat. There was a manual next to the blower unit inside the house and after looking through it I saw a diagram that showed a C wire was already wired. I simply connected it and bam, it started blowing cold air.

[@Mia-ht8oi]

@@ShoresLife Thank you for the response! We've made appt w/On Tech, for next week-earliest availability and that's who Google Nest recommended "partnering vendor for Nest". What a mess! Now having to pay another technician, but this time hopefully they get it right. 😅

[@ShoresLife]

@@Mia-ht8oi good luck! 🤞🏼

[@AJD-LsUp]

My wife is wanting to buy a nest for us, but we only have heat no central air I only have three wires green white and red. The red is connected to the R but jumped into the RC from the chat connect them together. My green wire goes into the G and my white wire goes into the W that’s all it’s connected. Can I buy the nest as is or do I need this $24 c wire adapter I have a honey will battery operated digital thermostat right now

[@ShoresLife]

I'm not a pro, so I'm hoping a pro reads this comment, but I remember when I purchased my Nest it was very specific that it didn't need a C wire and could run off the R wire, but it would only charge through the R wire when the unit was on. We had to set it up that way at our last home because it didn't have a C wire. There were a few times during the winter (it doesn't get super cold in San Antonio) when our unit wouldn't need to turn on because the temp was comfortable, and I'd have to pull the thermostat off and charge it manually.

[@howardkey6152]

I don’t understand this thermostat. I have red white and blue wires. Blue being labeled C. When I hook everything up nothing works. When I unplug it from the dock the thermostat will turn on. Put it back on the wall it shuts off and does nothing.

[@mcpain2006]

Tldr: read the install instructions, especially if you are a newb

[@TheBsmanatwork]

The c wire is to power the thermostat it’s not true that the ac related

[@gabrielavaldes1185]

I have a thermostat with four wire/ and batteries, no black wire, we connected the nest but no cold air would come out, could it be that it needs the “c” wire? Outside pipe started getting frozen, so we removed the nest and put the old one

[@zazenchuch]

How do you recharge it is not the red wire

[@ShoresLife]

from what I've read on the Nest site, if you have a C wire, the C wire gives the Nest a constant power source whether it's running or not (which has been my experience for the last year at our new place). If you don't have a C wire, then the red wire charges the Nest whenever the AC/heat kicks on, which explains why our Nest died a few times during the winter at our last home (it didn't have a C wire). Hope this helps!

[@eternal4633]

So the c wire is the blue one and it needs to be connected?

[@ShoresLife]

What I found out on my AC is the blue wire was the C wire, but it’s best to look up the manual online for your AC model number and confirm it has a C wire connection at the main unit

[@threestans9096]

the C wire is whatever color your wire is that is connected to the C terminal. Terminals are color blind.

[@JimEverette]

My battery 🔋 operated emerson blue light thermostat my blue common wire is not connected my ac isn't working, and furnace blows out 3 amp fuse

[@ShoresLife]

at my old place, my Nest could run ok without the C wire, but would only charge when the AC/heat came on (I think it used the R wire). During the winter when it didn't run a lot, the Nest would sometimes die on me. At our new place, I couldn't get the AC to run cold until I connected the C wire. No blown fuses, but just low pushed air through the vents that wasn't cold. What really helped me discover that this AC had a C wire was there was an instruction manual stuck to the side of the blower in the house and it had a diagram showing the C wire.

[@erickincaid9779]

This doesn't really seem like a tip.

[@mikemc4340]

Wasted a day with this and had to go to the old thermostat to get Ac. Very disappointed and will return

[@SundownCamry]

Have you tried charging your new thermostat on its own?

[@spudth]

Still doesn't splain it.

[@Ringowasthewalrus]

Wow those wires are embarrassing to look at

[@ShoresLife]

Yep! Looks like someone had chewed the plastic off before we moved in

[@thaolee192]

Bruh😂

[@fireflyaries]

Thank you! Just fixed my a/c w/this tip. Service call canceled! I’m in Texas so it’s been hotter than a mf in hell👿🔥☄️

[@ShoresLife]

Awesome! You made my day! Glad it helped. I’m in TX too, so I totally understand!

[@Dachamp2001]

No problem

[@Mariner687]

Don’t buy Nest

[@DJV94022]

Yup if a ac company recommends or pushes to sell it because they know theyll be back in couple of months selling you a ecobee or another ac part thats not damaged

[@leroyjenkins1380]

What if you don't have central air?

[@ShoresLife]

unfortunately, I don't have the answer. I did Google it real quick and it looks like it's compatible with different systems, but it suggests to call a professional to install

[@michaellupo3480]

If you want a smart tstat you need a C all the time. If its just a heat tstat u have right now it probably only has 2 wires. So you would need to install a common maker

[@ShoresLife]

@@michaellupo3480 interestingly enough, at our old apartment we didn’t have a C wire, but the Nest app ended up walking me through and using the R wire to charge the thermostat only when it was running the air though (which is all the time during the Texas summer 😁) We did have a couple times during the winter though when our unit wouldn’t run cuz the temps were fine, and the thermostat battery would die. Glad to have a C wire now though!

[@michaellupo3480]

@@ShoresLife yea exactly cause its giving a call for the ac to run so its gonna charge by the 24v power it got sent to it just by the ac. Up in the northeast so many people wanna just plug and play those things. And call for no heat. And it says recharge battery cause they dont have the constant power