I've used glow rods. They're rigid yet flexible. They also glow in the dark. They're helpful if there is insulation in the wall. Also, you might want to add that ppl kill the power to their furnace before working on it. I know it's only 24 volts but shortening out the board of the furnace is still a possibility
As someone going to school for hvac you really shouldn't mess with your ac unless you know what your doing you can cause some pretty big problems with small mistakes. Examples I didn't hear you saying anything about shutting off power to the air handler before messing with the t-stat wire also the way your stripping the t-stat wire is incorrect cutting into the insulation for the group of wire can cause shorts my preferred method is to grip the green wire and pull it down the length of the wire then cutting away the rest of the insulation but again most people should not be messing with this there's a reason people got to school for this
@@baconbot3106 I mean yea, there's ways to mess anything up in life. People go to school to be auto mechanics, but how many people do their own brakes or oil changes. You could say the same thing there. This is basic 101 type stuff. Any man with half a brain could do this. Now hvac installations and serious electrical work, yes, that should be left to the professionals. But this is not serious. Just take the proper precautions, and you'll be just fine.
I’m so glad I found this video as my Nest was losing Wi-Fi every day when the battery ran down. I went to look at my wiring and there was actually a fifth wire already running from thermostat to hvac that just wasn’t being used. It was super simple to connect it to the C wire in the basement and just plug it into the thermostat. 30min of research, about 3min of work, and my thermostat is back online! Thanks!!
It should be noted for anyone attempting this, that this can be extremely easy and can also be extremely difficult. If there is even just ONE staple inside the wall holding the original wiring it will cause you nothing but grief. Let’s say there is a staple but it isn’t completely tight to the wire. You’ll think that you are good to pull the new using the old, but it’s not only possible but very likely that once your tape joint connecting the old and new reaches that staple it will snag. Your first urge would be to tug a little harder and then uh oh, it comes apart and now you’ve got two loose ends inside a wall or floor cavity, neither of which is connected to your HVAC system. This can also happen with a hard 90 degree turn, or a hole that was only drilled wide enough for the smaller harness. As soon as that tape joint/splice meets resistance, you’re snagged. The only recourse is to start knocking out drywall to finish the job. Not trying to scare anyone, but I do this for a living, and I’ve seen it happen
Dropping wires should not be under rated in complexity. Good info and tape well, tight, and properly staggered with 3M super 88. A poorly taped end will also come apart easily leaving you up SHITE creek without a pull wire!
When I had a furnace replaced years ago, they had to run a whole new wire to a new location further down the hall because the original wires were probably stapled and wouldn't come out and it was too tight to get a new wire up to the original thermostat location.
One of your BEST tech videos. Upgrading my thermostat to Alexa enabled, I knew I needed a C wire, but your video showed me how easy it was to work with. I didn't have to pull any cables, and my system had an unused wire so I connected it to the thermostat and the a/c and I was done. Great video. (FYI I don't have a nest)
Two suggestions... 1. Agree with many comments below that thermostat wire may be secured in most instances by staple(s). So before snaking have someone hold low end and someone hold high end, pull back and forth to assess whether there is free play. 2. Use wiring lube to make sure that the "snaked" wire pulls through any holes... its $5 at any supply house or homey.
Mine isn't even run through the inside of the wall. It runs straight up from the furnace, into the stairwell, and through the wall behind the thermostat. It's just encased in plastic wire tracking.
Haha!! You know I have been trying to figure out how to fish a c wire and 5 seconds before you showed it I realized what you were about to say and got a huge smile on my face! Thx man!!
Thanks Brett. I was wondering why stringing a new wire wouldn't work. Now I feel comfortable buying a Nest. I will be putting the thermostat in a new location. My old wiring is not so easy to get at. Thanks Again
@@gloriahansen6727 the only time there was an issue was when I had a new furnace installed and power was off. Bat got a little low and internet disconnected for about 15 min until power was back on.
Hopefully my story will help someone. Last fall we installed a Nest thermostat at my sons house. The replaced thermostat was using 4 wires (no C), so we hooked the Nest with the same configuration. The furnace and Nest worked fine all winter. When my son switched to AC in early summer, there was a consistent clicking sound from a relay on the control board. It clicked nearly once a minute, and was aggravating. Though the AC seemed to run fine and shut off at temp. An HVAC guy came out and said that we had a bad control board. We replaced the board and the problem was still there. After watching this video, I decided to hook up a C wire. My sons existing thermostat cable had 8 conductors. So we hooked the unused blue wire up to C on the back of the Nest and then hooked the blue wire to C on the control board. The AC has run for over 24 hours with no clicking from a relay in control board.
Great tip on “reset”. We had a brief power outage of a few seconds that caused Nest to not recognize the c-wire! I didn’t have to do the full factory reset, just a restart! Thanks
Just wanted to say thank you for your video. I was helping out a neighbor with a new Nest Thermostat and found a blue wire unused. Connected both ends (furnace "C" terminal and the thermostat "C" terminal. It is no longer asking for the power connector.
Mine also needed the "C" wire. Without it I could not manually control the fan. But, I did not have to run any new wire. There were several unused wires inside the cable coming out of the wall. I simply connected the unused blue wire at each end. Now, my NEST is 100% functional.
Even easier way to do this. Just use the green wire to the city. Most people leave the fan in auto. The green wire is used to energize the fan when the fan is "on". As an hvac tech I have done this many times before. Replacing the state wire is not always as easy as shown. A lot of times the state wire is stapled to the wall studs. When we are working on a new construction job we run a 5 wire.
Thanks for the this, I noticed that there is now a 'Update Wiring' option on the Google Home App -> Thermostat -> Settings > Theromstat -> Wiring -> Update Wiring. So you shouldn't need to factory reset anymore.
Sadly, my Nest _appears_ to have a C wire connected, yet for some reason the fan runs randomly even though it's not setup to turn the fan on, which is annoying when it's cold out and it's blowing right on you. But thankfully you made this video which makes it really easy to see what sort of work it would take to set it up again (or at least know what to look at in order to fix it). Thanks!
Thank you very much, I was thinking of installing this since several months, end up installing it yesterday. Rewired as the c wire was missing.Had to cut one hole in the drywall. Didn't removed the old wire, lets see how it runs for few months and then no need to go back.
If you are lucky, sometimes there will be an unused conductor on the existing wire. You'll need to figure out where to connect the free wire on the furnace controller board C. Sometimes the original installer prefers to just use a battery thermostat rather than connecting to C. I was able to add C wire to my Nest in my first house and never had any issues. I actually did it for my parents as well, without issue. It's generally recommended to always use the C wire anyway, as there could be temperature inaccuracies or triggering delays when the thermostat achieves the set points.
Thanks for the video! in the end, I did not need the C wire. The Nest seems to work perfectly and has the motion sensing. Not sure why some systems need it and not others. Also, your wire was super easy. Mine is stapled inside the wall. That is code here, so you are not able to just pull it through the wall. As a FYI to everyone, before installing a new wire, I would see if you already have a C wire. It may not be hooked up at your furnace or on your current thermostat, but it may be there. For example, at my furnace, I can see the C wire. It was coiled around the other wires just to remove the excess. If you look at the wire in the wall, it too may have been coiled around the other wires and sits inside the wall, not pulled out through the wall. Unfortunately for me, the C wire as I said, was coiled up in the furnace, but I could not find it anywhere within the wall with the other wires. I cut open a pretty big hole, 4 inches by 2 inches to look down the wall, and it is not there. I wonder if they cut it away when they sent it up the wall because the wires have been removed from the main brown cable insulation and the individual wires were sent up the wall, which is very strange as they typically send the whole wire up in the main insulation and only remove what they need to send the individual wires out of the wall. Luckily, as stated above, I do not have a C wire error, so it seems my system can power it without the C wire!
That is great news and I should have put more emphasis on the fact that some systems just don't need it. The Nest Thermostat detects if it is needed or not depending on your system. It's great to hear you didn't have to go through the hassle of adding it.
I think you have the Nest and not the Nest E. His is the cheaper version Nest E from the looks of it. The regular Nest that retails for $250 doesn't need the C wire and everything works. I even had it connected with only 2 wires and everything works.
@@nicolaslocke1433 I have the newest version as was in this video with the glass screen (Nest Thermostat). The Nest E was a cheaper version than the Learning Nest which was 3rd generation. It was white with a foggy looking screen.
@@nicolaslocke1433 I have the same thermostat as you and it only worked with no C-wire for about a day for me. Some people 2 weeks, some people 18 months before they had to recharge it.
@@Mikegee63 I think that's because the 2 wires supplies very low voltage, and the boiler needs to stay on. I do notice my Nest on the boiler had a low battery indicator, but when checked, it still have a voltage of 3.724 ish. If I leave it alone and don't constantly bring the screen up, it went up to 3.79 eventually. Can't seem to get it to 3.8. the Nest on my AC does have a charge of 3.8 and never shown a low battery, but that uses 3 wires, Y, G, and Rh. But thanks for letting me know. I'll keep an eye on it to see if I ever need to unplug it and recharge it, as I only had these for a month.
I'm adding 18/8 so I can have my thermostat control the whole house humidifier as well (it only needs 1 or 2 additional wires for this, depending on the humidifier)
I first installed the Google Nest Thermostat on my Mr. Heater garage heater, without the C wire. The heater would continuously cycle until I installed the C wire.
WARNING: try this at your own risk! I tried this, but the taped connection was too thick to go through a point (I imagine it being a hole that's just big enough for the wire itself). I had to pull the new cable back out from the thermostat hole, and I broke the taped connection. Now I have the old wire dangling somewhere inside the wall that I can't see and don't know where. What a disaster!
Update: after a few days of trying, I was able to fish out the lost old wire in my wall with the help of a flexible rod, a homemade hook, and an endoscope camera. I carefully redid the joint between the old and new wire to make sure it's not thicker than the wire itself and I was able to make it through. The spirit of my story is that you want to make sure the joint is not thicker than the wire itself so it won't get caught inside your wall because most likely the wire goes through some small holes.
Forgot to mention to turn off power before removing wires. Or cutting into wires. Turn power back on last. If wires touch 24 volt will or could burn up your board
Highly recommended, my Nest was great the first week and then it starting pulsing my furnace during its recharge draws causing the furnace to turn on and off rapidly which is definitely not healthy for long term life. If you have the means, get the common connected.
@@misterpro7903 Awwww that's cute of you to respond and I appreciate that. Older versions of Nest Learning Thermost such as the recent 3rd Gen do NOT use AAA or AA batteries but a rechargeable lithium-polymer battery.
@@misterpro7903 you seem to be oblivious of this yourself which is quite humorous making your reply further worthless and you should be ashamed in yourself with such a petty retort. I am happy to hold your hand on this one though. This video is clearly about using a c-wire with a Nest in general, regardless of the generation and your reply offered nothing in regards to this as the c-wire reduces the need to rely on any battery functionality in the first place. Further more, the pulsing issue is a well known and documented issue which is covered in major reddit threads and articles and occurs with the newest version here as well. For example: myfyveproducts.com/blogs/news/no-c-wire-install-a-nest-thermostat-at-your-own-risk
@@Davideturner You only look like a fool trying to justify your mistake. Either state the exact model in your original post or erase it so you don't mislead anyone. That's all lmao
You can update the wiring in your home app on mobile. You don’t need to do a factory reset. Steps to do this on your mobile : Select your thermostat on home app >> settings (gear wheel) >> thermostat (under device features) >> Wiring (at the bottom section) >> Update Wiring
This is exactly what I was looking for. I have a Sensi WiFi thermostat, with essentially the same problem. I can use batteries for WiFi, but they don’t last long. My thermostat is directly over my furnace as well so it should be an easy project. Thanks!
@@Blackdog4818 I have an Emerson Sensi thermostat, which requires 2 AA batteries. Before running the new wire, I had to replace the batteries about once a month. The WiFi would really drain it.
Yes, a C-Wire will save your a lot from the hassle of not having one. Without a common wirre the thermostat pulls power from both hearing and cooling. If the AC unit has it's power shutoff for winter or you have dual zone a Common wire is recommended.
What I have been told, and actually verified by my own experience about "pulling" wire is: Don't!! May sometimes be O.K with small cables, but on a bit bigger ones you have to PUSH and then only Collect whatever loose length there is. That is particularly true when the cable has to go into a conduit. If you pull, one or other of following things happen. First, you peel the cable insulation and risk a short circuit. Second, you pull the conduit along with your cable. Third, with multiple cables in one conduit, at least the last one wedges between the existing ones and then all are locked in -- no pushing or pulling releases them any more.
What pisses me of is my system actually has 5 wires at the furnace but it appears the common wire was chopped off behind the existing thermostat. I can't run a new wire without relocating it due to how it was stapled down inside the plenum.
You show a forced air furnace system c wire install only, can you kindly do a video on an instant hot water/boiler radiant system c wire install please?
I had an interesting problem with our Nest Thermostat; any load I placed on our two-wire system started the furnace (think; the power it drew to run the Nest). Let me explain further… I started out with a two-wire system, Red and White, Red=Power, White=Call-for-Heat, the legacy thermostat was a standard mercury bi-metal coil. I installed the Nest and I tried placing Red on Rh and the White wire on W1, but the furnace ran constantly. So I ran and added a ‘C’ wire, I kept Red on Rh, the White on W1 (Call for heat), and the C wire, or common to the furnace. The furnace still ran constantly. The Nest thermostat functions by using a small amount of current from the furnace to, 1. Operate, and 2. Keep the batteries charged. I did some testing and ANY current draw over 6 milliamps starts the furnace. Testing with a ‘C’ (Common) wire still drew a small current and fired up the furnace. I found the markings on the furnace to be very clear, Power, Common, and Call for Heat. To be clear, W1 on the Nest is ‘Call for Heat’, the ‘C’ is common and R1 is 24 vac or power. This is not rocket science, if I draw any current from any of the wires it starts the furnace. I’m thinking there must be something screwy with the vintage furnace, vintage 1995. My initial solution was to remote the 24vac power and supply the Nest power from it, however simply placing the ‘Call for Heat’ wire (W1) on the Nest (along with the common wire), the furnace would start. Finally, I remoted the entire mess, I added a small relay and 24vac transformer in a project box near the thermostat and ran five wires up to where the Nest is mounted. Now everything works well… The takeaway here is, not all furnaces are created equal…
Hi Brett and thanks for the helpful video! I see you have what appears to be a swamp cooler fan switch on the wall next to the Nest. Have you connected that to the Nest? If so, how does one do that? Thanks!!😀
Just finished installing 2 of these and running new wiring plus c wire in a house built in the 1800s. Talk about a “fun” job. 95% of these thermostats need a common wire. Even if you install it without out one eventually you’ll be calling a tech back out bc of issues occurring I.e battery or function issues. The other 5% is that a customer has a older control board like a ewc-st-2e with seperate O and B wired and have to be upgraded.... a complain I have is that this newer model has to be added through the google home app which for some reason never goes through smooth while setting it up. Takes several attempts to sync up. I feel the nest app connects easier to nest products. But that’s going away smh.
If you get the error "e294 Red wire not connected", and the "skip the blue" wire trick did nothing. I did this: I had W, G, C, Y, and R wires. During the install process, the app will ask you what wires you have. On my 8th attempt to solve this error code, I unchecked the box next to R and checked the box for Rh. You made need to factory reset the thermostat and start the install over from the beginning if you get the e294 error code just so you can get the wire select screen in the app. The Google Home online help is worthless.
appreciate the video.. very helpful but I returned my Nest as I'm not going into my ceiling and run wire... or hire someone to do this... this should be solved by Nest...
Went round and with nest technicians for months. They never said that we had to spend more money to rewire our home. They just should have told us we were screwed from the start. Wasted so much time and money. Nest folks should be ashamed.
This video is very helpful- just have a quick question- we are basically replacing the old wire with a new one? The new one has the extra for the C wire? Thank you!
Correct. My install was pretty easy because of the location of the furnace and the Thermostat and yours might not be so simple. What Thermostat are you using? There is now an option to get a connector so you don't need to rewire. Here is the one for the new Nest Thermostat: th-cam.com/video/tgAiEBqUXIk/w-d-xo.htmlsi=SH75zYyJEW-3n2Es
@@TechWithBrett Thank you! My furnace is close to my thermostat because I live in a condo so I've looked and seems easy to do. I have a nest learning pro- I'll check out the other video thanks!
Oh crap I got the blue one and didn't know that it was c wire im gonna hook that up today after work and its funny I'm not getting the notification for it either
After watching your install video, happy to see that you did this video, too. Thanks! So, to confirm, if you have TWO Nest thermostats (upstairs and downstairs), one would need a C wire for both, no?
I’ve tried installing a C-wire adapter on my Trane furnace/ac for my Honeywell thermostat and have been unsuccessful. When I re-wire everything the thermostat has power and air will blow, but it’s not cool air as I want and the outdoor unit doesn’t run… any idea what I might be doing wrong?
I have a Question. I am installing a lock case and need to remove the nest thermostat so I can screw in the backplate of the lock case. Do I need to reset the nest to do that? Thanks. Great video btw.
Don't forget to turn off power to your furnace before removing the thermostat. If you short the wires to ground you'll be wondering why your furnace doesn't work anymore. Hint it's hopefully just the 24v fuse in the furnace.
Yes, the white single pole service switch that was shown actually was “on” in the up position, maybe the circuit was turned “off” at the circuit breaker.
Is this for real? In most cases thermostat wire is secured in the wall. What is shown here is not normal and won't be the case for vast majority of people
WHAT IS A C WIRE? I disconnected my old thermostat and there was a blue wire and a yellow wire NOT connected. The only connected wires were Red, White and Green. Are one of the yellow or blue wires a C wire?? What is a C wire for??
If you have a powered thermostat system would you still have to use batteries with this device. I’m planning on buying one but I don’t wanna have to constantly put batteries in it when an a common/power wire is in place.
This process ended up being a lot easier than I thought. Do you have any tips for routing a new cable that is in a more difficult spot?
I've used glow rods. They're rigid yet flexible. They also glow in the dark. They're helpful if there is insulation in the wall. Also, you might want to add that ppl kill the power to their furnace before working on it. I know it's only 24 volts but shortening out the board of the furnace is still a possibility
As someone going to school for hvac you really shouldn't mess with your ac unless you know what your doing you can cause some pretty big problems with small mistakes. Examples I didn't hear you saying anything about shutting off power to the air handler before messing with the t-stat wire also the way your stripping the t-stat wire is incorrect cutting into the insulation for the group of wire can cause shorts my preferred method is to grip the green wire and pull it down the length of the wire then cutting away the rest of the insulation but again most people should not be messing with this there's a reason people got to school for this
@@baconbot3106 I mean yea, there's ways to mess anything up in life. People go to school to be auto mechanics, but how many people do their own brakes or oil changes. You could say the same thing there. This is basic 101 type stuff. Any man with half a brain could do this. Now hvac installations and serious electrical work, yes, that should be left to the professionals. But this is not serious. Just take the proper precautions, and you'll be just fine.
Don't install a nest read my post
You comment on google video of video google home
I’m so glad I found this video as my Nest was losing Wi-Fi every day when the battery ran down. I went to look at my wiring and there was actually a fifth wire already running from thermostat to hvac that just wasn’t being used. It was super simple to connect it to the C wire in the basement and just plug it into the thermostat. 30min of research, about 3min of work, and my thermostat is back online! Thanks!!
I'm so glad this could help!
Thank you for sharing your story same situation so thankful !!
It should be noted for anyone attempting this, that this can be extremely easy and can also be extremely difficult. If there is even just ONE staple inside the wall holding the original wiring it will cause you nothing but grief. Let’s say there is a staple but it isn’t completely tight to the wire. You’ll think that you are good to pull the new using the old, but it’s not only possible but very likely that once your tape joint connecting the old and new reaches that staple it will snag. Your first urge would be to tug a little harder and then uh oh, it comes apart and now you’ve got two loose ends inside a wall or floor cavity, neither of which is connected to your HVAC system. This can also happen with a hard 90 degree turn, or a hole that was only drilled wide enough for the smaller harness. As soon as that tape joint/splice meets resistance, you’re snagged. The only recourse is to start knocking out drywall to finish the job. Not trying to scare anyone, but I do this for a living, and I’ve seen it happen
Drywall is easy! I live in an old house and the walls are plaster and furring strips.
Solid, good sound suppression.
Pain in the neck to work with!
Dropping wires should not be under rated in complexity. Good info and tape well, tight, and properly staggered with 3M super 88. A poorly taped end will also come apart easily leaving you up SHITE creek without a pull wire!
Agreed 100% …. People definitely need to be aware of this
Hahahaha (eternal laughter). No thanks
When I had a furnace replaced years ago, they had to run a whole new wire to a new location further down the hall because the original wires were probably stapled and wouldn't come out and it was too tight to get a new wire up to the original thermostat location.
One of your BEST tech videos. Upgrading my thermostat to Alexa enabled, I knew I needed a C wire, but your video showed me how easy it was to work with. I didn't have to pull any cables, and my system had an unused wire so I connected it to the thermostat and the a/c and I was done. Great video. (FYI I don't have a nest)
You have an Ecobee, and don't need a C wire, it comes with an adaptor kit.
I have been following you for years, there is no one better than you explaining and giving solutions, thanks for your videos ...
Two suggestions... 1. Agree with many comments below that thermostat wire may be secured in most instances by staple(s). So before snaking have someone hold low end and someone hold high end, pull back and forth to assess whether there is free play. 2. Use wiring lube to make sure that the "snaked" wire pulls through any holes... its $5 at any supply house or homey.
yellow 77
hehehehehe..... lube
Holy crap, that looks way easier then I thought it would be. Thanks for the vid!
Dude you rock... I just saved $120 for an hvac tech to come out and install c wire. Thank you so much!
Damn that’s cheap people trying to charge me 175-500
You were VERY lucky you fished that line through so easily. My luck mine will have been stapled to the studs all the way down. 🤦🏻♂️
Brutal
Mine isn't even run through the inside of the wall. It runs straight up from the furnace, into the stairwell, and through the wall behind the thermostat. It's just encased in plastic wire tracking.
@@pthibault630 u do know they have an official adapter now.
@@FaiyazC Yep. This is cheaper and easier though.
@@FaiyazC can I attach the adaptor to the best hookup instead of the furnace?
Thanks. You just made a cold day warm again for my family. Only took an hour including the trip to the store
Haha!! You know I have been trying to figure out how to fish a c wire and 5 seconds before you showed it I realized what you were about to say and got a huge smile on my face! Thx man!!
Thanks Brett. I was wondering why stringing a new wire wouldn't work. Now I feel comfortable buying a Nest. I will be putting the thermostat in a new location. My old wiring is not so easy to get at. Thanks Again
Had mine installed over a year without a c wire and still working great!
Does it ever get disconnected from the wifi or the battery dies faster?
@@gloriahansen6727 the only time there was an issue was when I had a new furnace installed and power was off. Bat got a little low and internet disconnected for about 15 min until power was back on.
I have 4 wire. Worked fine for a year then suddenly gave e298 error.
Hopefully my story will help someone. Last fall we installed a Nest thermostat at my sons house. The replaced thermostat was using 4 wires (no C), so we hooked the Nest with the same configuration. The furnace and Nest worked fine all winter. When my son switched to AC in early summer, there was a consistent clicking sound from a relay on the control board. It clicked nearly once a minute, and was aggravating. Though the AC seemed to run fine and shut off at temp. An HVAC guy came out and said that we had a bad control board. We replaced the board and the problem was still there. After watching this video, I decided to hook up a C wire. My sons existing thermostat cable had 8 conductors. So we hooked the unused blue wire up to C on the back of the Nest and then hooked the blue wire to C on the control board. The AC has run for over 24 hours with no clicking from a relay in control board.
Great tip on “reset”.
We had a brief power outage of a few seconds that caused Nest to not recognize the c-wire! I didn’t have to do the full factory reset, just a restart! Thanks
Just wanted to say thank you for your video. I was helping out a neighbor with a new Nest Thermostat and found a blue wire unused. Connected both ends (furnace "C" terminal and the thermostat "C" terminal. It is no longer asking for the power connector.
Great job explaining! This is exactly my issue and I’m going to try this tomorrow. Thank you!!!
Mine also needed the "C" wire. Without it I could not manually control the fan. But, I did not have to run any new wire. There were several unused wires inside the cable coming out of the wall. I simply connected the unused blue wire at each end. Now, my NEST is 100% functional.
Even easier way to do this. Just use the green wire to the city. Most people leave the fan in auto. The green wire is used to energize the fan when the fan is "on". As an hvac tech I have done this many times before. Replacing the state wire is not always as easy as shown. A lot of times the state wire is stapled to the wall studs. When we are working on a new construction job we run a 5 wire.
Thank you!!
It's a good idea in case you afraid of losing the cable when you pull through the wall
Glad I saw this video. Wasn't sure how I was going to feed the new wire.
Didn’t even think of using the old cable to fish the new one. Smart!
Thank you for the wiring walk through, i was able to rewire the unit properly and the heat is on!! thanks again Brett.
Great to hear!
Thanks for the this, I noticed that there is now a 'Update Wiring' option on the Google Home App -> Thermostat -> Settings > Theromstat -> Wiring -> Update Wiring. So you shouldn't need to factory reset anymore.
Sadly, my Nest _appears_ to have a C wire connected, yet for some reason the fan runs randomly even though it's not setup to turn the fan on, which is annoying when it's cold out and it's blowing right on you. But thankfully you made this video which makes it really easy to see what sort of work it would take to set it up again (or at least know what to look at in order to fix it). Thanks!
Thank you very much,
I was thinking of installing this since several months, end up installing it yesterday.
Rewired as the c wire was missing.Had to cut one hole in the drywall.
Didn't removed the old wire, lets see how it runs for few months and then no need to go back.
Great vid! Good to know to factory reset after the C is installed. 👍
99 out of 100 times the wire has been run through studs or has a staple that will prevent it from being pulled back. You got LUCKY.
If you are lucky, sometimes there will be an unused conductor on the existing wire. You'll need to figure out where to connect the free wire on the furnace controller board C. Sometimes the original installer prefers to just use a battery thermostat rather than connecting to C. I was able to add C wire to my Nest in my first house and never had any issues. I actually did it for my parents as well, without issue.
It's generally recommended to always use the C wire anyway, as there could be temperature inaccuracies or triggering delays when the thermostat achieves the set points.
Also remember if it’s too hard on one end , you can always try to pull from the board to the thermostat end . One way is always easier than the other
Photos...especially of the furnace panel, are really important. I thought I fried the motherboard, but I had connected one wire wrong.
Happy ThanksGiving Bred
Happy Thanksgiving to you!
Thanks to the front man of Queens of the Stone Age, I now know how to connect the C wire!
Actually, no one knows.
Great video. Made this mystery less mysterious. Really appreciate it.
Thanks for the video! in the end, I did not need the C wire. The Nest seems to work perfectly and has the motion sensing. Not sure why some systems need it and not others.
Also, your wire was super easy. Mine is stapled inside the wall. That is code here, so you are not able to just pull it through the wall.
As a FYI to everyone, before installing a new wire, I would see if you already have a C wire. It may not be hooked up at your furnace or on your current thermostat, but it may be there. For example, at my furnace, I can see the C wire. It was coiled around the other wires just to remove the excess. If you look at the wire in the wall, it too may have been coiled around the other wires and sits inside the wall, not pulled out through the wall.
Unfortunately for me, the C wire as I said, was coiled up in the furnace, but I could not find it anywhere within the wall with the other wires. I cut open a pretty big hole, 4 inches by 2 inches to look down the wall, and it is not there. I wonder if they cut it away when they sent it up the wall because the wires have been removed from the main brown cable insulation and the individual wires were sent up the wall, which is very strange as they typically send the whole wire up in the main insulation and only remove what they need to send the individual wires out of the wall.
Luckily, as stated above, I do not have a C wire error, so it seems my system can power it without the C wire!
That is great news and I should have put more emphasis on the fact that some systems just don't need it. The Nest Thermostat detects if it is needed or not depending on your system. It's great to hear you didn't have to go through the hassle of adding it.
I think you have the Nest and not the Nest E. His is the cheaper version Nest E from the looks of it. The regular Nest that retails for $250 doesn't need the C wire and everything works. I even had it connected with only 2 wires and everything works.
@@nicolaslocke1433 I have the newest version as was in this video with the glass screen (Nest Thermostat). The Nest E was a cheaper version than the Learning Nest which was 3rd generation. It was white with a foggy looking screen.
@@nicolaslocke1433 I have the same thermostat as you and it only worked with no C-wire for about a day for me. Some people 2 weeks, some people 18 months before they had to recharge it.
@@Mikegee63 I think that's because the 2 wires supplies very low voltage, and the boiler needs to stay on. I do notice my Nest on the boiler had a low battery indicator, but when checked, it still have a voltage of 3.724 ish. If I leave it alone and don't constantly bring the screen up, it went up to 3.79 eventually. Can't seem to get it to 3.8. the Nest on my AC does have a charge of 3.8 and never shown a low battery, but that uses 3 wires, Y, G, and Rh. But thanks for letting me know. I'll keep an eye on it to see if I ever need to unplug it and recharge it, as I only had these for a month.
From what I understand, from both Google documentation and forums, you have to do a factory reset to make the Nest itself detect the C wire.
Much appreciated! I just installed mine today with your instruction.
Hey Brett, love your videos. Can you make an updated smart home tour video for the end of 2020?
That would be great.
That's the plan! Somebody just needs to come clean my house first.
I'm adding 18/8 so I can have my thermostat control the whole house humidifier as well (it only needs 1 or 2 additional wires for this, depending on the humidifier)
I first installed the Google Nest Thermostat on my Mr. Heater garage heater, without the C wire. The heater would continuously cycle until I installed the C wire.
U can use the neutral of the transformer for your c wire from your mr heater. Hook a wire up to it and to your tstat c terminal
Great video, thank you
WARNING: try this at your own risk! I tried this, but the taped connection was too thick to go through a point (I imagine it being a hole that's just big enough for the wire itself). I had to pull the new cable back out from the thermostat hole, and I broke the taped connection. Now I have the old wire dangling somewhere inside the wall that I can't see and don't know where. What a disaster!
Update: after a few days of trying, I was able to fish out the lost old wire in my wall with the help of a flexible rod, a homemade hook, and an endoscope camera. I carefully redid the joint between the old and new wire to make sure it's not thicker than the wire itself and I was able to make it through. The spirit of my story is that you want to make sure the joint is not thicker than the wire itself so it won't get caught inside your wall because most likely the wire goes through some small holes.
@@genegene2417 put the thermostat in a different location.. it uses WiFi to control.. can be ANY WHERE in the house
Coming from Hvac you got lucky it’s a 50/50 shot every time some aren’t stapled anywhere some are 100’ long and stapled 50 times in the run lol!
Forgot to mention to turn off power before removing wires. Or cutting into wires. Turn power back on last. If wires touch 24 volt will or could burn up your board
This was VERY, Very helpful. Many thanks!
Highly recommended, my Nest was great the first week and then it starting pulsing my furnace during its recharge draws causing the furnace to turn on and off rapidly which is definitely not healthy for long term life. If you have the means, get the common connected.
Google nest uses 2 non rechargeable AAA batteries so how can there be a recharge draw lol
@@misterpro7903 Awwww that's cute of you to respond and I appreciate that. Older versions of Nest Learning Thermost such as the recent 3rd Gen do NOT use AAA or AA batteries but a rechargeable lithium-polymer battery.
@@Davideturner Well this video is not about a 3rd gen or older versions so why even comment
@@misterpro7903 you seem to be oblivious of this yourself which is quite humorous making your reply further worthless and you should be ashamed in yourself with such a petty retort. I am happy to hold your hand on this one though. This video is clearly about using a c-wire with a Nest in general, regardless of the generation and your reply offered nothing in regards to this as the c-wire reduces the need to rely on any battery functionality in the first place. Further more, the pulsing issue is a well known and documented issue which is covered in major reddit threads and articles and occurs with the newest version here as well. For example: myfyveproducts.com/blogs/news/no-c-wire-install-a-nest-thermostat-at-your-own-risk
@@Davideturner You only look like a fool trying to justify your mistake. Either state the exact model in your original post or erase it so you don't mislead anyone. That's all lmao
Very good my friend for your help I will do that to my one tomorrow
You can update the wiring in your home app on mobile. You don’t need to do a factory reset.
Steps to do this on your mobile :
Select your thermostat on home app >> settings (gear wheel) >> thermostat (under device features) >> Wiring (at the bottom section) >> Update Wiring
Thanks for the info. It looks like that was updated since the video released.
I just bought a 2020 google nest thermostat - Charcoal, Appreciate your tips before I install the device.
This is exactly what I was looking for. I have a Sensi WiFi thermostat, with essentially the same problem. I can use batteries for WiFi, but they don’t last long. My thermostat is directly over my furnace as well so it should be an easy project. Thanks!
Wait, I have to put a battery in my Nest? Mine just came in the mail, and I thought the red wire was the power?
@@Blackdog4818 I have an Emerson Sensi thermostat, which requires 2 AA batteries. Before running the new wire, I had to replace the batteries about once a month. The WiFi would really drain it.
Okay so it's a rechargeable battery with the 3rd generation Nest thermostats. So luckily, it recharges whenever the furnace power goes on.
Simply use ADD A WIRE DEVICE or disconnect G wire and connect on C terminal
Yes, a C-Wire will save your a lot from the hassle of not having one. Without a common wirre the thermostat pulls power from both hearing and cooling. If the AC unit has it's power shutoff for winter or you have dual zone a Common wire is recommended.
Thanx for the video and all the info in the comments👍
What I have been told, and actually verified by my own experience about "pulling" wire is: Don't!! May sometimes be O.K with small cables, but on a bit bigger ones you have to PUSH and then only Collect whatever loose length there is. That is particularly true when the cable has to go into a conduit. If you pull, one or other of following things happen. First, you peel the cable insulation and risk a short circuit. Second, you pull the conduit along with your cable. Third, with multiple cables in one conduit, at least the last one wedges between the existing ones and then all are locked in -- no pushing or pulling releases them any more.
Appreciate your help explaining patiently and easy to follow 👍
This helped me so much. Thank you!
Very clear and helpful, thanks
Except most installers staple the HVAC control wire to the studs and beams! Good luck getting a good home run pull, if that is the case...
What pisses me of is my system actually has 5 wires at the furnace but it appears the common wire was chopped off behind the existing thermostat. I can't run a new wire without relocating it due to how it was stapled down inside the plenum.
Very informative. Thank you so much.I am going to install soon. My motion sensor is not working due to C wire missing in Nest thermostat 2020.
My motion sensor worked fine without a c wire.
Great video didn't expect that.
You show a forced air furnace system c wire install only, can you kindly do a video on an instant hot water/boiler radiant system c wire install please?
Also, make sure you pull a couple extra feet of spare cable for a service loop, on both sides of the run, your future self will thank you!
I had an interesting problem with our Nest Thermostat; any load I placed on our two-wire system started the furnace (think; the power it drew to run the Nest). Let me explain further… I started out with a two-wire system, Red and White, Red=Power, White=Call-for-Heat, the legacy thermostat was a standard mercury bi-metal coil. I installed the Nest and I tried placing Red on Rh and the White wire on W1, but the furnace ran constantly. So I ran and added a ‘C’ wire, I kept Red on Rh, the White on W1 (Call for heat), and the C wire, or common to the furnace. The furnace still ran constantly.
The Nest thermostat functions by using a small amount of current from the furnace to, 1. Operate, and 2. Keep the batteries charged. I did some testing and ANY current draw over 6 milliamps starts the furnace. Testing with a ‘C’ (Common) wire still drew a small current and fired up the furnace. I found the markings on the furnace to be very clear, Power, Common, and Call for Heat. To be clear, W1 on the Nest is ‘Call for Heat’, the ‘C’ is common and R1 is 24 vac or power. This is not rocket science, if I draw any current from any of the wires it starts the furnace.
I’m thinking there must be something screwy with the vintage furnace, vintage 1995. My initial solution was to remote the 24vac power and supply the Nest power from it, however simply placing the ‘Call for Heat’ wire (W1) on the Nest (along with the common wire), the furnace would start. Finally, I remoted the entire mess, I added a small relay and 24vac transformer in a project box near the thermostat and ran five wires up to where the Nest is mounted. Now everything works well…
The takeaway here is, not all furnaces are created equal…
Well Done. Thank you
People are looking for a solution to just having 2 wire that is not able to be required wish there was a video that explains that
Hi Brett and thanks for the helpful video! I see you have what appears to be a swamp cooler fan switch on the wall next to the Nest. Have you connected that to the Nest? If so, how does one do that? Thanks!!😀
Just finished installing 2 of these and running new wiring plus c wire in a house built in the 1800s. Talk about a “fun” job. 95% of these thermostats need a common wire. Even if you install it without out one eventually you’ll be calling a tech back out bc of issues occurring I.e battery or function issues. The other 5% is that a customer has a older control board like a ewc-st-2e with seperate O and B wired and have to be upgraded.... a complain I have is that this newer model has to be added through the google home app which for some reason never goes through smooth while setting it up. Takes several attempts to sync up. I feel the nest app connects easier to nest products. But that’s going away smh.
You missed showing us how to connect the A/C unit
Another great video... thanks!
very good information thanks
Great video! Clear and concise!
My nest worked fine for a year. 4 wire. Motion sensing was fine. It suddenly started with the e298 error. Reverted back to programmable unit.
If you get the error "e294 Red wire not connected", and the "skip the blue" wire trick did nothing. I did this: I had W, G, C, Y, and R wires. During the install process, the app will ask you what wires you have. On my 8th attempt to solve this error code, I unchecked the box next to R and checked the box for Rh. You made need to factory reset the thermostat and start the install over from the beginning if you get the e294 error code just so you can get the wire select screen in the app. The Google Home online help is worthless.
Awesome job
appreciate the video.. very helpful but I returned my Nest as I'm not going into my ceiling and run wire... or hire someone to do this... this should be solved by Nest...
Went round and with nest technicians for months. They never said that we had to spend more money to rewire our home. They just should have told us we were screwed from the start. Wasted so much time and money. Nest folks should be ashamed.
This video is very helpful- just have a quick question- we are basically replacing the old wire with a new one? The new one has the extra for the C wire? Thank you!
Correct. My install was pretty easy because of the location of the furnace and the Thermostat and yours might not be so simple. What Thermostat are you using? There is now an option to get a connector so you don't need to rewire. Here is the one for the new Nest Thermostat: th-cam.com/video/tgAiEBqUXIk/w-d-xo.htmlsi=SH75zYyJEW-3n2Es
@@TechWithBrett Thank you! My furnace is close to my thermostat because I live in a condo so I've looked and seems easy to do. I have a nest learning pro- I'll check out the other video thanks!
Thanks man
Nice info great tutorial.👍
Oh crap I got the blue one and didn't know that it was c wire im gonna hook that up today after work and its funny I'm not getting the notification for it either
They made a new device called Nest Power Connector. It's easy to install at the furnace end and doesn't need the C wire.
After watching your install video, happy to see that you did this video, too. Thanks!
So, to confirm, if you have TWO Nest thermostats (upstairs and downstairs), one would need a C wire for both, no?
Nice job
Adding new wire option is in the app only. No need to reset.
I’ve tried installing a C-wire adapter on my Trane furnace/ac for my Honeywell thermostat and have been unsuccessful. When I re-wire everything the thermostat has power and air will blow, but it’s not cool air as I want and the outdoor unit doesn’t run… any idea what I might be doing wrong?
Nice video brett
never run a 18/5 always use 18/8 you will thank me later especially if ya plan to replace your unit with a two stage or you end up having a bad wire
Good job
I have a Question. I am installing a lock case and need to remove the nest thermostat so I can screw in the backplate of the lock case. Do I need to reset the nest to do that? Thanks. Great video btw.
I have only 2 wires. Hooked it up in Summer worked fine till today . Any help appreciated.
Don't forget to turn off power to your furnace before removing the thermostat. If you short the wires to ground you'll be wondering why your furnace doesn't work anymore. Hint it's hopefully just the 24v fuse in the furnace.
Yes, the white single pole service switch that was shown actually was “on” in the up position, maybe the circuit was turned “off” at the circuit breaker.
This is true starting from Gen 1. They just didn't tell anyone about it.
Is this for real? In most cases thermostat wire is secured in the wall. What is shown here is not normal and won't be the case for vast majority of people
WHAT IS A C WIRE? I disconnected my old thermostat and there was a blue wire and a yellow wire NOT connected. The only connected wires were Red, White and Green. Are one of the yellow or blue wires a C wire?? What is a C wire for??
What if you thermostat doesn't have a C wire port?
FYI, Google released a C wire substitute for Nest thermostats: The Nest Power Connector.
I cannot include a link in the comments. Oh, well...
I don't have the c wire installed and everything works fine
I don't have a C wire and My Motion sensing works and no battery issues. I have an OB wire so not sure if that mattered.
If you have a powered thermostat system would you still have to use batteries with this device. I’m planning on buying one but I don’t wanna have to constantly put batteries in it when an a common/power wire is in place.
My blue wire goes to Y on the houses thermostat. Is that correct?
I'm doing this instead of buying the nest power connector... thoughts??
If you have easy access and don't have to spend a ton on cable it might be worth it, but the Nest Power connector is pretty simple to install.
Hi
What is E260 error? I don't have a C wire and I get this error which prevents the thermostat from being connected to my phone or wifi.