How To Install A Common (C) Wire: The Easy Way

[@Justin-bw8zi]

I just wanted to thank you SO much for this video. Game changer. Sounds crazy, but you really impact people's lives for the better. We have an old boiler (that works great) but doesn't have the power for the nest unit. Local contractors are not smart home educated (nor necessarily want to be) and thus we were really stuck. I am not the handiest nor have any idea re:wiring, but your example was SO simple. I bought the adaptor off your link, showed up the next day, 5min install and BOOM. PERFECT. My son was so excited it all worked. Thank you so much, real people watch these and real families benefit. Many thanks

[@PT-km9jq]

Very useful solution. I followed the instructions and fixed my problem at ZERO cost - I ran a wire from the existing door bell transformer (also 24 ACV) located in the basement right below the thermostat in the dinning room above.

[@FamilyFirst137]

So this kind of worked for me, then after a little more research and this guy has a full break down of all the different slots on the base of the nest. What some people were doing was leaving the RH wire were it was (instead of removing as he states in this video) and also placing in the transformer wire. What I did that worked for me was leave my original wires where they were, I put 1 transformer wire in C and the other in RC. He stated in the other video that RC and RH are the same exact thing but one is for cooling and one is for heating. But if you have a cooling system AND a heating system this won’t work, in my case I only have a heating system hooked up to the nest so this worked for me. Thank you to the person that created this video.

[@anon-4419]

This comment was very helpful to me because I believe it cleared up my confusion. and I wanted to say thank you for that. Just to be sure though, I have rh and w wire for heating. Instead of putting one transformer wire in rh, I can put that one in RC? (& of course the other transformer wire in the c slot)

[@FamilyFirst137]

@@anon-4419 so I’m no professional but I did a lot of trial and error and searching online. For the last 11months I have been using the 2 thermostat wires from my boiler to Rh and W1 and then my 24v transformer wires are going to C and RC. This guy has another video where he goes into a little more depth… m.kzbin.info/www/bejne/eXSxep6laM6Nf6c skip to 6:40….

[@davefolan4425]

I did the same thing. I have a forced hot water/ radiant heaters, no fan or a/c. Mine was a 2 wire, and after following your instructions, it still didn't work. I added the low voltage plug/charger. The existing Red went to RH, the existing White went to W1.The transfomer wires went to C, I pulled the Red, and put the 2nd transfomer wire to RH. The furnace would'nt start. So, I took the loose Red wire and put it in with the transformer wire to the RH port. And all works fine now. It's showing 200mA in the Technical Info setting. And the furnace turns on. Thank you, I would never have figured this out on my own.

[@scottmartinezguitarandbass]

This worked brilliantly! Thank you!!! I should say, I had a wire in my RC terminal and I needed to solder one of those transformer wires to it so both would be able to use that RC port. That worked just fine. I just tinned the transformer wire and wound it around the RC wire - touched it with a touch of solder, then plugged the RC wire into the NEST port. Worked like a charm.

[@rodtinberg6468]

Thanks for posting this. I had to do the same thing. It would not work without the existing Rc wire connected.

[@jm309767]

Just had to do the same thing. I had to add a bridge from R to Rc.

[@AnubhavShah]

this is very useful video for many people. Although it is good, you should replace it with one that actually demonstrates the installation to the wall so people could see what different scenarios would look like. For example, i have 2 wires, and will be only using one as you mentioned (the w) while the existing wire that used to go to Rc, will sit idle/unused (if i understand you correctly).

[@anon-4419]

This was my understanding as well. May I ask if you installed it and were successful?

[@AnubhavShah]

@@anon-4419 this was a while ago. let me know if you need me to check my config, but i will say it is working for me now. i only have heat, but yes it works. although note: i have switched to ecobee, and am thinking of switching to new nest thermostat perhaps this winter. I personally need to know how much time the heater is running (total hours) so i can truly gauge cost and usage. honeywell doesnt do this, and ecobee is vague at best.

[@CarlGreen01]

Thanks!

[@OneHourSmartHome]

Thank you for watching and the super thanks! It really helps support the channel!

[@ralphavoc7025]

For those with a Nest E thermostat that the transformer didn't work for them, I found a solution that works for me. When I pulled the red wire and put the 2 transformer wires in "R" and "C", the furnace fan wouldn't turn on although under "equipment" in thermostat settings showed that it was working. In desperation, I put the red wire back in the "R" hole along with the transformer wire, and low and behold, the fans work and shows under "equipment" in settings as working as well. So basically, I left all the wires in original spots and then put the transformer wires in "C" and "R" (along with the original "R" wire.) Let me know if that worked for anyone else.

[@Madrigall74]

Ralph Simmons THANK you man! I tried this fix in the video and it took my whole system offline. Using your trick worked and saved me at least $100-$200 in service calls.

[@OneHourSmartHome]

Ralph thanks for sharing the helpful information!

[@chrisscottlynn]

One Hour Smart Home I was reluctant to try this but it 100% was what my system needed. R wire from the furnace was needed. Added one of the transformer wires to it and the other to the C and nothing blew other than sweet sweet room temperature air.

[@OneHourSmartHome]

@@chrisscottlynn Glad to hear it worked! Thanks for the feedback and informative comment.

[@iamco698]

Thank you so much!!

[@bowlagravy]

Thank you so much for your great videos. One adjustment I had to make was, the transformer wire went to Rc and C and the original red wire went to Rh. Then it worked.

[@davehightower3570]

Thank you so much for sharing this video. I added that exact nest thermostat to my barn infrared heating system which was a two wire system, and needed to add the external C wire. I tried to figure it out myself and it wasn’t right. By watching your video, I was able to see that I had my two external power wires flipped around. I will now go back and reinstall it by putting the two additional wires in the correct order. Thank you for keeping it simple but well explained. I installed the latest nest system in my house and that went well, as my system had a c wire so it was an easy install. Thanks again

[@derv206385]

At 2:35 where does the RH wire from the wall connect to now?

[@bokneeza]

By far, this is the easiest way I’ve found. Thank you sir ✊🏼

[@michaelbalsamo3752]

I'm confused you show in the first part putting the transformer wire to Rh and c but than at 4:02 you say it's plugged into RC and the c wire I plugged into RH and C and it says detected no power at c. Am I missing a step?

[@thomasjohn8183]

Your videos were very informative and has also helped fix my nest thermostat. Thank you so much 👍 For this video I had followed your instruction but reading through the comments, I found out that I had to connect Rc or Rh wire along with the transformer (adaptor) wire to make it work.

[@georgelopez5369]

Decent fix, only 1 issue that could surface. Not all a/c contractors pass through the drain pan safety float switch with the yellow(cool) wire, sometimes they break the red. So if your drain lines get clogged and your pan fills up there is nothing to cut the power to your condenser. Just make sure your float switch breaks the yellow or condenser wire before you do this or you could possibly have water overflowing into your ceiling.

[@physiques]

I don't have a C wire and will be running one like you showed but I have a RH and RC wire attached in the RC and RH spot. Would I then connect one of the transfer wires with the wire already in the RC spot and the other in the C spot? I've been searching online and thankfully came across your video which is most close to my situation. I greatly appreciate any help you can offer 🙏

[@badcomma]

I thought this would get me through my latest Nest obstacle, but it didn't. The Nest says everything is good to go, no error messages, but it's not turning on my cooling. Your videos are good. I've learned more about HVAC than expected.

[@hosegooseman5]

Thanks for this information and presentation. Very easy to do. Only issue was that had to connect the R together with the power adapter R and problem solved. Any other way the Nest didn’t recognized the power adapter. 😎

[@marka.bradley8392]

Thank you for doing this video, Google Support would not help unless it was their C-Wire adapter. Following along with your video I was able to get this going. The only issue was I found out that I had to connect Rc or Rh wire along with the transformer (adaptor) wire to make it work. This was the only change that was needed and once I got this done. Everything worked like a charm.

[@mikerisner]

A Quick Additional Note: Check to see if there is a C/Blue wire in the wire bundle. In my home, I found that the installers cut the blue wire to the point where I could not see it. I dug into bundle a bit deeper and found it. YES!! So I wired it up at the thermostat and in the HVAC unit. From 20 mA input to 200 mA. Success! I gained a tremendous amount of knowledge watching this video. It really raised my confidence when modifying the wiring behind my thermostat and at the HVAC board. Thanks!

[@ysacarcampero4378]

Where did you connect it in the hvac unit?

[@arminius301]

Don't forget to mention that you should always unplug the HVAC unit first before hooking up thermostat wires etc. so the control board is not energized or you run the risk of blowing on-board fuses, capacitors or other electronics, been there done that! It'll save you a huge headache or a $200 bill in parts!

[@brandondp94]

Hi, Love your nest thermostat videos! I ordered an AC transformer/adapter like you recommended which plugs into your typical wall outlet - as I have two nest thermostats which utilize the boiler for heat (radiant on one, baseboard on the other), and utilize the A/Cs on their respective floors. So my wire set-up is the odd one you touched on briefly (Y, G, and RC. W and RH). The problem I'm having is the nest short cycles the boiler and will make it kick/click on and off repeatedly and too rapidly. I connected the A/C transformer to both RH and C, as I lack the common wire, but it didn't recognize the Common Wire. Can I connect the transformer to both the RC and RH only, and cap those existing wires? Thank you very much in advance!

[@j808010]

This is a very good video. But, I do think you will need to do some update at least in the description. Adapter is providing current to Rh from different loop than R from furnace. If you let the original R wire floating (dangling). Some machine won't work if the machine measure the 24V from it's R to ground. Although Nest doesn't recommend to add two wires in one terminal. But, I agree with some of the comment below, you will need to add the R wire and +24 from adapter together at Rh or Rc.

[@mickael486]

Can I use that transformer in his link and hook it up to C and R? My 2020 model Nest doesn't have Rh or Rc. 😔

[@TransparentUtoptia]

Finally got my Nest working, thx!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

[@OneHourSmartHome]

Great to hear! Thanks for watching and the comment!

[@marlearenee9801]

Hi I have another type of nest and mine only has 6 spots: Y C W G R *OB. I have 2 wires from my old thermostat: W and R I put a C wire in just like that one. Do I still remove my R wire? Please help

[@MatrixProHD]

I had the same problem. Unfortunately that transformer doesn’t work for that particular thermostat. That’s the main reason why im forced to upgrade to the learning thermostat

[@txjoey]

COMMENT AND QUESTION: At time stamp 3:55 you stated to connect wires from the transformer to the RC Terminal and C terminal. Per your video, I should be RH and C. A few comments say to RECONNECT RH Wire from HVAC back to the RH Terminal. IS THAT CORRECT????

[@jjs211u]

Hi, I wonder if the furnace will ever go on with Rh from the furnace not connected? Maybe your house has a cooling only system?

[@christopherlikins6321]

I have been up and down through forums and videos trying to square the circle of why some people say a fan relay is needed and others seem fine without one. Some people hear their furnace hum and buzz until they put in a relay, others put in the relay and the system doesn't work. I have a millivolt gas valve hooked up to a thermocouple that when switched on powers the valve and turns on my fireplace. I hooked up a wifi thermostat with a 24v ac adapter, wired it up and everything worked. The reason why my millivolt gas valve didn't overload is because my thermostat doesn't have a battery and so draws a constant 22-27volts from the ac power supply. I ran a multimeter at the end of the thermostat wire that hooks up to the fireplace and the voltage was in the millivolt range because the thermostat was pulling 99.9% of the available power and so there was only crumbs left to push to the gas valve. My thermostat doesn't have a battery, and I wonder if (in units with a battery) when the internal battery is charged how much load goes down the wire to the fireplace and if that could overwhelm the millivolt gas valve. In my circuit the fan relay was not functional because the thermostat took all the voltage there was not enough to trip the fan relay. I took the thermostat out of the circuit and tested the fan relay with the 24v ac adapter it functioned normally. The only concern I have is if the wifi thermostat fails and stops drawing power and the circuit to the fireplace is active could there be a chance that the 22-29 volts from the ac adapter gets shunted to the fireplace? The thermostat manufacturer seemed to think that when the unit fails all circuits are cut as a safety precaution. Would that be the case in a battery powered unit? I think I will install a small fuze inline at the fireplace so that it trips just in case the voltage gets diverted in the case of thermostat failure. Also to ensure that the fireplace works when the power is out I wired up the on off switch on the fireplace as a bypass. Hope that helps someone! edit: Thank you to everyone including the creator of this video who ran tutorials on how to install these systems. Having so many examples really helped me tease this out. It takes a lot of time and planning to put these videos together and that work deserves respect.

[@vktse]

Chris, did you use a fan relay after all? I have a minivolt heater as well and would like to have it work with Nest Thermostat 3rd Gen.

[@christopherlikins6321]

​@@vktse I want to say that I am in no way an electrician and this is based on a conversation with a technician and a theory. I did not use a fan relay. The thermostat I used consumed between 99 and 100% of the power provided by the ac adapter so when the thermostat switched to "heat on" and closed the circuit for the fireplace there was almost no voltage available to go to the fireplace and so made sure that I wasn't overwhelming the millivolt gas valve on my fireplace. I couldn't get the fan relay to work in the system because it required 24v to activate the switch and that voltage made available by the ac adapter was being consumed by the thermostat. I would hesitate to use this on a thermostat with a battery because the small voltage from the battery could increase the voltage available to the system beyond the needs of the thermostat and push more than millivolts to the gas valve. You could use a multimeter at the the ends of the wires before they connect to the fireplace to confirm though that the available voltage at that point isn't above millivolt capacity. I would also say contact the manufacturer and try to confirm that in the event of a thermostat failure the mechanism fails and disconnects all circuits. You wouldn't want a situation where the power is being supplied to the unit, but the unit malfunctions and isn't drawing power while the circuit to the fireplace is closed and then all the available voltage is being supplied to the millivolt gas valve. I had a lot of luck calling the manufacturer and running ideas past the technician, and calling local electricians and fireplace servicers to pick their brains. They were also confused as to how everyone was diy-ing these thermostats without causing more house fires, it seems the pool of voltage being almost entirely consumed by the thermostat leaving only millivolts for the millivolt fireplace is the most likely scenario. The small amount of spillover available when the circuit for the fireplace was closed ended up being perfect for my system because the millivolts in the circuit weren't enough to travel to the thermostat and back. The last little umph made the system more reliable. The KZbin comment section isn't the best place to describe something this technical so if you have any other questions let me know and maybe I could email you some diagrams.

[@harrisonfowler4461]

So what happens to the R wire we disconnected? Wasn’t that going to the furnace? How is the furnace going to turn on now?

[@dantolvtvar9767]

Ever get an answer to this? ?

[@thomaskelly5496]

Can you put both the old R wire and R wire for the AC adapter in the same spot? I'm in the same boat, my nest doesn't have Rc and Rh, only six spots to put the wires.

[@BergenInc]

Im in the same boat as well! I only had a w and r wire at the thermostat, i ran a 24v tansformwr and connected to r and c, but the nest now says it doesnt detect a W. This was installed a gas furnace.

[@bretthurlbut9159]

I actually just did this yesterday but for the 2020 google nest thermostat. I followed the instructions in the video and ended up capping and tucking away the red wire from the furnace. Welp... What happened was the thermostat was powered and no longer have me errors, but I noticed that the temp in my house was dropping and the furnace wasn't kicking it. I started looking at other smart thermostat 2 wire videos and one I found said that you can keep the red wire from your furnace in with the wire you put into the R spot from the transformer. I decided to give this a shot as the temps in my house were falling fast. And my furnace started kicking in after that, and has been working fine since. I don't want to put any damaging advice out there given that this is an important part of your home, but in my specific case it worked.

[@mikecolon7420]

@@bretthurlbut9159 I am having the same issue, two wires and won’t turn on with the original R left unhooked? Do you have a link to the video you are referring to?

[@syzygyxv3359]

so at 4:15, ur saying the (from boiler)red wire would also be in Rh with the addition of the one of the adaptors wire. or is the from boiler red wire "discarded" all together. at 3:58 you say the adaptors go in the Rc and C. But at the end you dont have the red from boiler wire and its still working. So im just alittle confused

[@rebecca285]

Thank you for the super helpful video. I'd been scratching my head over how to make it work for a while. Finally got it installed today thanks to you!

[@thomaschong3915]

Your videot gave me the confidence to do it myself. However, like some have commented, I had to leave the rH wire in place in order to get it to work. Thanks again.

[@Kpewters]

Hi James! Thank you SO MUCH for your easy to follow video!!! I just purchased the Nest Learning Thermostat to replace my “retro” two wire thermostat. I ordered a 24v transformer like the one in your video (ac/ac...?). This is for a gas boiler system for hot water baseboard heat. I hooked up the wiring as you suggested (W1, C=24v, Rh=24v leaving the furnace Rh wire disconnected) and I was unable to get heat. It wasn’t until I spliced the 24v wire with the RH wire and hooked them both into the thermostat Rh connector that I was finally able to get heat. I am SO not an electrician or HVAC person AT ALL and concerned that I may have done something wrong...? Please let me know of your thoughts.

[@Kpewters]

Btw....if you’re reading this today (and I hope you are not)....Happy Thanksgiving!!!

[@akhtarkh]

After splicing the R wires, if your nest is turning your boiler on and off as desired then you should be fine. Two wires coming into your old thermostats is just like two wires coming into a common switch to turn your light on and off. Thermostat is just a temperature controlled switch. Smart thermostats along with switching your boiler or furnace or ac on and off, needs power to run and stay connected to internet. That is why you need two power lines coming in to complete the circuit to feed power to smart thermostat.

[@Kpewters]

Makes total sense....thank you!

[@OneHourSmartHome]

Thanks for the answer comfort zone, I agree with your analysis.

[@Mikegee63]

Thanks Kathi!!! After reading how you got your system to work, I decided to give it a shot this morning because I've tried different ways of hooking up my system after watching many videos and reading the comments and the closest I got was the thermostat not sending any era codes but not actually heating. Your way was the last straw for me before I hired someone. After hooking up wiring, I put the face back on and within seconds I heard the sweet sound of hot water running through my baseboards!!!! The next time I need an HVAC person, I'm hiring you!!!!

[@PepsiManX360]

My gas steam boiler has 2 wires white and red. So would I put white to W1 & red to RH and then the transformer to RC & C?

[@udflyers87]

This was incredibly helpful and easy to follow. Thank you.

[@OneHourSmartHome]

You're welcome.

[@tonnyygames5976]

@@OneHourSmartHome without my red wire, my system wont kick in. Help me

[@NyxT-GyreX]

@@tonnyygames5976 hey how are u? Mine does not kick in either what did you ended up doing 🤔

[@k00lboricua]

I don't have an outlet near any of my 2 zones thermostat. Any solution?

[@DriftKr6l]

Great videos. I subscribed. Question: My Nest Thermostat e does not have two R terminals, only one, how can I add a C wire via a transformer in this case?

[@OneHourSmartHome]

First try the transformer with just the r and c wire. Don't connect the r wire from the hvac system. If that doesnt work connect the r wire from the hvac system and one wire from the transformer both into the nest r terminal. Then connect the other wire from the transformer to the c terminal.

[@chrisscottlynn]

See Ralph’s comment below. I was in the exact situation. His comment works perfectly. I’m sure there might be some ancient furnaces that might have an issue but mine is 20 years old and works perfectly configured as he’s written.

[@VinodKumar-hj9km]

@@OneHourSmartHome Is connecting R from HVAC to transformer right thing to do ? In case there is any voltage difference between these two, then it will cause undesired flow of current.

[@fliphusker]

I rarely ever comment on YT videos but I want to say, you are awesome!!! Local company came out and hooked up my AC after I had it moved and had them install a Nest 3 gen. Could not get anything to work, no power on the Nest. I almost did this myself but was worried about 2 wires connected to the common at the furnace. They needed to come back today and told him about your fix. He was skeptical and thought I needed a new Nest. He redid the wiring and BAM!!! Fixed. Thanks, you saved me hundreds of dollars!!!

[@OneHourSmartHome]

That is awesome! Thanks for your support!

[@SeasideSilence]

I have read that the Nest has an internal jumper between Rh and Rc. If I add this transformer, can I remove my Rc wire? Or should I leave this in?

[@1UTUBEUSERNAME]

You need to leave the jump ON between RH and RC. RH is Red Heat and RC is Red Cool. Both require voltage which is why they are connected together with the jumper.

[@steveo6420]

Great video. I watched a couple and yours was the most concise and informative. Thank you!

[@OneHourSmartHome]

That's great to hear! Thanks for watching!

[@tjn442nash5]

I ran the common like you show because my nest showed a power problem .. however the A/C and fan still won't turn on … I had to leave the red for the A/C to get it not to show a problem only heat !! any idea's

[@whodunit79]

The video for the transformer on amazon shows connecting the transformer wires to C and RC. Then you would still have the red going to RH. Then they hook a jumper from RC to RH. I haven't tried this, but it seems as if it should work.

[@handsoffanomaly7]

Aha, I've got a red wire connected to Rc, but no wire connected to Rh. I guess that's why the unit stayed charged during the summer when we moved in but lost charge when we switched to heating the house. I'll try the recommended transformer and hook it up to C and Rh. Any problems leaving the Rc hooked up as is when I add the transformer? Thanks-

[@Zarathustra-H-]

Great video. I'd appreciate some feedback please. I have my nest running a central AC unit with an R, Y and G wire. (connected to Rh, G and Y) In that configuration it would often go into a delayed mode, presumably due to insufficient power. I decided to add the 24vac transformer. Regardless of which method I hook it up with (either removing the Rh wire, and connecting the transformer to Rh and C, or leaving all three wires in, and connecting the transformer to Rc and C) once the 24vac transformer is connected, the system is not responding to the thermostat. Remove the transformer, and the system responds again. Any idea? Is it just a bad transformer somehow, or is the system not compatible? Appreciate any assistance anyone can provide.

[@Zarathustra-H-]

I should follow up. Discovered that the system was going into delay mode due to a condensation cutoff switch. The drain was clogged, and the condensate was backing up triggering the off switch. This is what was resulting in the delayed mode. Cleared the drain, no more delayed mode. Never got the transformer to work, but in the end didn't need it.

[@ttaperss]

Re: The system not responding to the thermostat when the transformer is connected. I came across the same problem and had to follow the installation for a 2-wire configuration by connecting the existing Rh wire and the second transformer wire into the same R port (either Rh or Rc). Reference kzbin.info/www/bejne/r5qYnJmkaMege80

[@johnbocelli6086]

Thanks for the informative video, instead of the plug in transformer an I run an 18 gauge wire from an existing 24 volt transformer right to the C terminal on the Nest and leave all other wires as is?

[@babysneaks2034]

Thanks for the video -- it gave me some hope. I have a Nest Learning Thermostat that had its battery drain during a three day record heatwave when the a/c was running for long stretches. I have had the Nest for three years, and I never had an issue prior to this. Google told me to spend $500 getting a C-wire installed by a Nest Pro (they did not pitch the Nest Power Connector). I thought instead I would try this solution to prepare for the next record heatwave. When I plug the transformer wires into C and Rh, I get lots of power to the thermostat but the hvac does not operate, even though the Nest indicates the heat, a/c or fan are running. When I move one transformer wire from Rh to Rc, the same thing is the case. When I have the transformer plugged into C and Rc and keep the old red wire in Rh, I get the N72 error on the Nest. No combo works. Google states the Nest bridges between Rc and Rh automatically, so it seems like I need not try removing the red wire from Rh and bridging the Rc (with one of the transformer wires in it) and the Rh. Anyone know what I am doing wrong?

[@citrusgoldfish]

i want to know the same thing!

[@michaelmarch8719]

Try what Ralph Simmons recommended in his comment below. I had exactly the same issue as you and nothing I did worked.... until I put the R wire back into the original Rh terminal (along with one of the transformer wires). The other transformer wire went in C as the video mentions. And you are right that Google says the Rh and Rc terminals are connected, so I'm not sure why shoving two wires in the Rh terminal is any different then putting one in Rh and one in Rc. But I'm not gonna complain about it now that my fan is finally running again XD (Note that Google technically says not to put two wires into the same terminal because you could damage the terminal, so try at your own risk)

[@erorr4o4]

Thanks, can we use the same on amazon Honeywell smart thermostat?

[@puttaraksaanurak8408]

I was trying yesterday and it doesn’t work. Need help

[@MimmyJoe]

Eve Alisa did you get any help?

[@yazenaswad5918]

Thank you. Can this be done for the nest thermostat in an RV?

[@neamaghobrial95]

So I have 4 wires G Y1 W1 and Rc, do I connect the transformer in C and the other in together with the red wire in arc? So Rc will have two wires?

[@briancox3501]

I have 4 thermostats (zoned heating). Could I use one transformer to power multiple thermostats (proximity for wiring is not a problem), or do I need a separate transformer for each thermostat?

[@traciwaugh2624]

I appreciate this information. I purchased the transformer, only problem is I don't have a connection in the rh terminal at the thermostat, I have connection to the rc terminal. Now I'm stuck. Help if you can

[@sylrider]

Can I connect my nest with my navien tank less water heater. The thing is running every 10 minutes night and day! It's supposed to be on smart mode. Thanks so much for your videos and your help!

[@matthewwatson5115]

The Thermostat E only has Y1/G/R/W1/C/OB* connections. How do I wire the seperate transformer to this?

[@OneHourSmartHome]

You would wire the transformer:amzn.to/31C70Hq in the R an C terminals, and you would take out the R wire from the HVAC system. But your HVAC system may not need a common wire. You should always attempt to install it without the common wire first.

[@JDMHaze]

R is same as RC/RH which Are the same thing doesnt mater which 1 it is

[@njmom829]

@@OneHourSmartHome I'm having this same issue now. I bought a transformer and realized I don't have both r and rc to plug both wires into. Wouldn't unplugging the hvac r wire and plugging in a transformer wire not allow it to turn on though?

[@guraaba]

@@njmom829 I have the same issue. Did you get any solution?

[@raymondlee0215]

@@njmom829 i am having same issue. Any solution?

[@MohamedElshorafa-e9y]

Not sure if this was already asked but would this work for an old steam boiler/radiator system? The wires I have are the "W" and "R". I just bought the Google Nest 4th Gen Thermostat but was advised that it wouldn't work great without a C-wire. Any help or comments with prior experience with this would be greatly appreciated.

[@richard_rouzeau]

FYI, Google released a C wire substitute for Nest thermostats: The Nest Power Connector.

[@fraliexb]

But you still need to mess with the furnace wiring

[@richard_rouzeau]

@@fraliexb I would say that it's still much better than running a C wire from the furnace all the way to the thermostat.

[@fraliexb]

Yeah but this video is more for people who don't want to mess with the furnace. I tried to use the plug and it didn't work for me. Sigh.

[@ricardonash944]

This was helpful...however I have have the Nest E thermostat and the battery has died a few times this year so I'm looking for a transformer to add so my battery will stay charged...how to I install the common wire transformer to the Nest E 1st gen thermostat on a boiler heat only system...any information will help...thanks.

[@eduardocortes6705]

Hi! Where you able to figure this out?

[@LBSNor1234]

Why doesn’t NEST use a couple of AA batteries to avoid this???

[@philkingmke]

Cuz they're gigantic and ugly? Silly question.

[@SAUCE206]

Nest used two tripple a’s that’s to power the controller. The common wire is to give constant power flow to and from the furnace.

[@williambracey811]

Because these smart thermostats drain batteries too quickly

[@spudth]

But this "solution" doesn't involve the furnace?!​@@SAUCE206

[@sandracormier2121]

Depends on your Nest. Newer gen has rechargeable, older ones use AAA batteries

[@kenhowell8403]

How about if the forced air heat only system has just a white and red wire? Additionally, my Nest has only Y,C,W,G,R and OB terminals? How do I hook up the power adapter? Thanks.

[@GenZyannd]

how can a dangingly R wire come a loop? don't you need 2 wires connected to the system to make a call?

[@darniusterix5774]

Found the answer from a shopper on Amazon who had the same problem. Your a life save Nancy. Here is here solution: The instructions are very vague. I have a 3rd generation Nest thermostat, since my Rc was already in used, I used the Rh instead, but I got an error and the thermostat was stuck on the error message, so I learnt the two white cables are not the same they have different polarity there's one with black lines that one is power and the other one goes on C, so I used Rh and C that gave me an error that I was allowed to ignore it, but nonetheless the error was there so I kept on researching and tried putting the power (black lines cable) on Rc with the one that was already there, that way the Nest doesn't detect anything on RH an uses the internal jumper to close the circuit, I guess I could have used the jumper that comes with it, but my solution was better in my opinion, see in the photo attached my configuration, is working perfectly 👌🏼 Customer image

[@javiervilla244]

Sounds good for a smart home installer hacker, but as an HVAC tech, you run into the risk of damaging your control board or nest thermostat. The power from the wall transformer will get mixed with power from the furnace transformer and will overheat one or the other if they are running in different frequencies. Use a NEST POWER CONNECTOR or call an HVAC tech to avoid a hack that could cost you more than what doing things right would cost, to begin with.

[@tob187sr]

No one complaining but you !!

[@BeaterBlade]

Hi James. Thanks for this video...saved my butt! It took a bit of reading down below, but in my case I had to keep the RED wire from the wall in RH and put the other Transformer wire into RC & C. Whew...the school of Hark Knock learning. Got you a cup of coffee too. Thanks much.

[@ericimi]

Where would you plug it in lol

[@bryanjackson215]

Seriously though lol

[@elixeroflife]

the wall adapter has 25ft of cord on it, can fish it through the wall along side the original thermostat wire bundle and plug it in at the furnace

[@comachocomacho6581]

Hi, if the Thermostate needs a trasmeter just to make it works as a sourse of 24 volt. can I just put a jump connection between R and C. ? thank you so much.

[@CuZn7030]

Rename this video “what a common wire does” - there is no depiction of how to actually install this adapter in this video

[@afevis]

It's literally at 2 minutes dude, watch the video instead of skipping through

[@CuZn7030]

@@afevis oh gee he explains how to connect the wires to the labeled thermostat without actually showing the furnace end. Like any moron couldn’t figure that out

[@afevis]

@@CuZn7030 The adapter doesn't connect to your furnace dude, it goes to the nest base lol

[@Zomby_Woof]

​@@afevisdon't be obtuse. Sure, one end connects your thermostat. The other end connect to the the hvac control panel on your furnace, a/c, heat pump - whatever. Thats the end he's asking about

[@afevis]

@@Zomby_Woof This video is literally for a power transformer that PLUGS INTO YOUR WALL, not your furnace controller. Those connections STAY THE SAME as they were before. If you need a guide for how those are set up, then you obviously don't know how an HVAC system works and shouldn't be touching that end to start with.

[@mickymini9147]

I have heat and cool system with R G W Y wires and want to install ecobee premium thermostat , I want to use transformer adapter shown in this as home doesnt have C wire, in which slot this transformer wire should be connected? Please if anyone can help. Thank you

[@MrOffshore]

If I was hooking this up in my RV to an LP furnace (heat only) can I run a 12V wire to power this the same way as the transformer?

[@vitaminarc0106]

Thanks for this....question.....I just bought a Nest Gen3. My thermostat is meant to only power AC (heat is separate thermostat). Old set up is RC, Y, and G. When i set up new Gen3, compressor keeps powering on and off. Does this mean that I should be installing a C wire ? Is that my issue here ?

[@epino3209]

So after I connect the two white wires from the transformer to RH & C what do I do with the original RH wire that was on the thermostat?

[@sfltrades]

Hi, thanks for this info and all others' smart gadgets, I have a question, and my AC coes do not have a common. My nest only has 6 ports ( Y1, G, R, W1, C, *OB), and only the common is open. My nest drain every year, so I charge it, I try this the other day, but I think I damage the capacitor. I am in FL, no furnace, only electric heat on aAmerican Standards/ Trane. How can I connect this power transformer? Since the red has power all the time, can I use it as a common?

[@jay9890]

QUESTION - First hi and thanks for the video. I have three Nest thermostats - two work great - they only control heat. My third Nest controls heat for the second floor and the whole home AC. This Nest is constantly losing battery during the summer. The heat and AC are separate units and the wiring to the trouble Nest is the following; heat white wire - W1, heat red wire - RH, Air red wire - RC, Air green wire - G and Air white wire - Y1. I’m hoping an AC adapter will fix my constant low battery problem in the summer. Do I need to make any changes to the Air wire set-up, or just hookup the AC adapter as you suggest? Thanks.

[@sparkwebdesign]

Around 2:10 in the video you connect to C and RH, and you said that's all you need to complete the circuit and charge the thermostat. But then at 3:55, you say you need to connect to RC and C. So which is it? C and RH, or C and RC? Thanks.

[@dbscout]

Nice hack. Personally the need for a semi-local outlet precludes this for me, but this is a great option. Nice vids dude, keep it up

[@timtedesco3961]

You don’t need a local outlet to the thermostat. If you have 18 gauge thermostat wires running to the thermostat from the heating/cooling system, you can plug the transformer in next to the system and connect the two wires to the existing thermostat wire that runs to the thermostat. The wire is usually 18/5, so there should be some unused wires.

[@danielscott9137]

Might have to do this, just installed the nest power connector, will update. Atm after installing the nest power connector its at 20 Ma

[@samjam6989]

I have 2 wires. One for W and one for Rh. Also new nest doesnt have Rh and Rc and only has R. So should i just connect adaptor wire to C and R and leave the Rh coming out of furnace not connected to anything?? Would this not just keep the heat on all the time?

[@rosemarypetrone5150]

I have 2 red and 2 white for AC and heat (old systems). Tried wiring but only get 3.68 volts and 20 mA. Runs for a few hours but then the screen goes blank. Do I need 2 separate transformers?

[@BH-lp4sj]

What is the reason for my power lin dropping to 8 ma (o) after installing the common wire?? It was at 20 ma (o) without the wire but we ran into issues of the battery draining and dying on us in the middle of the night so I purchased this adapter.

[@iscan4u346]

hey bro. I have Y1, RC, W1, RH and G have wires from HVAC system for both heating and air conditioning. I get power from RH which charges the nest battery. but when in air condition mode, it doesn't charge. where do I put those one of the wires from (C) adapter? thanks for your video and help.

[@sergeantc4073]

I keep getting 'Delayed' too often.This may do the trick.Thank you sir

[@BDNADLER]

Time code 3:55, you said that you wire "it" (I assume you mean the adapter) into the RC and C terminals. When you physically wired the adapter, you wired it into the RH and C terminals. My red power wire is on the Rc terminal. My RH and C terminals (before installing the adapter) are vacant. I assume that in your statement on time code 3:55, you meant to say you wire "it" to RH and C terminals. Please clarify

[@rahulchowdhury253]

I have also posted a similar question. Looking for help

[@brianwehnert8469]

I would like to do it at my furnace and have one extra wire to the thermostat already. I am sure I could use that as the common or C wire but if I do it at the furnace do I tap into the red one there ? I hope you see this and btw I love your videos !

[@johngiancola8176]

Do we remove the wire that was on the Rh terminal and leave it disconnected and have the white wire from transformer on Rh and C?

[@avinashbhan2393]

Thankyou, very well explained........will it work if we add only additional C wire from nest to the furnace board, keeping the green wire the way it is connected......without changing or touching anything else.....Thx

[@Goodbrod]

My vac guy made a jumper from Rh to Rc, what would I do with that?

[@bourret]

thanks for your help. --hooking up transformer to power NEST--most directions are unclear as to whether or not you unhook the red thermostat wire from nest which goes to boiler --the answer is yes --you unhook it and put one of the leads from transformer on R on NEST. Thanks for the clarity.

[@louthedog11]

Hi James, I have a dual fuel system gas boiler baseboard heat and central air AC. Y1, G, Rc, W1, Rh. In your video you removed the Rh and connected the transformer to Rh and C, what should I do about my Rc wire?

[@Nevilando]

I have the same issue. What did you end up doing?

[@japatel42]

I have multi-zone oil heating. My current TT has 4 wires coming in but only the Red wire is connected to "R" and the Blue wire connected to "W". My Nest TT has Y, C, W, G, R and *OB terminals. I have two spare wires which I can connect to a 24V transformer at the other end. So, one can be connected to the "C" terminal but not sure where the other lead of 24V wire should be connected. Please advise. Thanks.

[@renj6531]

thanks this was a life saver Im not able to acces my furnace cntrl board because the unit is up on a 3 story roof and thats too high for me. but this kept me from doing that and Returning my Nest to the store because I really like it .

[@davefolan4425]

How do I wire a 2 wire gas furnace with a Nest controller for forced hot water and no fan. I want to add a low voltage charger/plug to the system as well.

[@craigheard2504]

Thank you. This was a great tutorial!

[@aronramirez638]

Hello, I just installed with the Rh and connector and Nest shows no power. When I check the screen shows 8ma. I bought another brand that is 300ma. The option that you recommended is 500ma. If I connect the red cable to Rh, the external power to C and Rc, Nest Google didn't work. It show no connexion. I have the Google nest Thermostat learning version 3rd. Generation. Thank you for your answer. Roberto

[@The_Margaret_Ann]

One question: when you hooked up the wires, you used the adapter wires for the RH and the C spots in the thermostat, and to leave the old RH wire from the wall detached, but later, when you summarized, you said to put the adapter wires in the RC and C spots. So here’s my question: if I have a heat-only system, do I hook up the adapter to the RH and C? Or to the RC and C? And do I use my old RH wire at all?

[@Sophomore451]

I am going crazy trying to find something that works with my boiler heat only. Can this work with two wires coming from the old one that is 110 volts?

[@OneHourSmartHome]

No, you would need a high voltage smart thermostat. Something like Mysa: amzn.to/3SXh6ji might work but you would need 3 wires, a load, neutral and hot wire to install it. Thanks for watching!

[@VUMMIDI1]

Hi, thank you for posting this video. It made it very easy to install a power adapter to my Google thermostat

[@austinwinchester]

Opened up the thermostat and there was a red wire running to rh and then from rh to rc. I got a common wireb adapter like yours i disconnected the rh and rc all together like you suggested. ran a common wire to c and rh like you said but what about the rc? obviously whoever did this before me thought we needed power to rc so i sent a wire from rh which is the return wire for the adapter i assume. Lmk if this is a fine way to power it and ill lyk if my house catches fire

[@bwtinhfx]

Hi guys, not sure if you are still watching this space .... Thanks for the video. My site is a cabin, HVAC installed probably state of the art 20 years ago. Electric boiler, in floor hydronic heat, three zones. I wanted to connect a nest instead of the existing thermostat for the largest zone so that we could turn on the heat hours before arriving in the winter. I originally had a two wire (Rh and W) thermostat in place . I connected a transformer to the nest exactly as you suggested, left the Rh wire free, reconnected the W. The nest loved this, showed no errors. However, no hot water filled the pipes in the zone I was working on. I believe that the valve for that pipe was not triggered to open (cold pipe below the valve, warm above). I wonder whether the Rh wire that I left disconnected is required for the valve circuit. Accordingly, I wonder whether I could splice the old Rh wire into the Rh connector on the nest, and therefore also to one pole of the transformer. In other words ... old Rh wire to transformer wire, with a third leading out of that connection into the Rh slot on the nest. Thoughts? Risking cataclysm? Any ideas welcome .... Thanks again for the video.

[@YaDerty]

Hey. Currently having the same issue. Looks like in the other comments, the move is to leave the two wires as is (W and RH). Then connect the two adapter wires into C and RH (two wires in same spot). Trying that today.

[@Synchrimedia]

So the power in from the furnace is not connected at all? You're getting power from the transformer instead of the furnace connection? I'm doing a 2 wire (red and white) system. I got the Google Nest Power Connector and hooked it up as best I could as per instructions, but although the furnace would turn on, it would go off again after a few seconds and just keep cycling on and off, never actually giving any heat. Is that due to not having enough power to run the Nest? This new Nest has 2 AA batteries in it too. Not sure what they run.

[@HauntedHomeCreations]

Question… I have the 24 volt transformer however the 2 wires on the transformer are braided. The Nest set up guide states the nest will not work with braided wire. Did I purchase the wrong transformer? Or disregard the warning about braided wire?

[@dianebadolato4930]

Hi I can’t find the link for the transformer ?

[@tabusboss]

I just found this video and followed the direct as indicated. The Nest is giving me an E72 error message. I have a 2 wire, oil fired steam radiator system. Any suggestions?

[@aznsam24]

Can u call for summer fan control on "G" with this setup?

[@todivetoday]

Great video, thank you, I am struggling with no C wire going into my unit. Just bought a transformer and will let you know if it worked. Thanks again. Cheers