How to install a Thermostat (C-wire adapter)

[@alannewhall2323]

I just installed an Amazon smart thermostat and your video is spot on. I needed a c-wire adapter and the one Amazon sold for it was the Honeywell you used. Everything was the same. Made this so much more easy to install. Thank you

[@lorihuttner1703]

I cannot thank you enough. I needed to install the C wire adaptor and went I looked at videos on that I got totally taken down a rabbit hole. I even had videos pulling new wire! Ugh! Yours is the first one that was absolutely clear about what do do. And you had proper lighting by furnace so I could actually see what you were doing! Thanks so much!! With your help I should be able to do my install tonight.

[@HomeRepairHub]

I appreciate the feedback. Glad the video helped

[@1974chm]

I don’t have a c I have yellow wire do I put the blue together with the yellow wire

[@FREDERICKEUSEBIO-d3q]

I just wanted to thank you for this video. I had a slightly different setup so when I followed your steps it still didn't turn on. I had to connect the R wire to the RC slot on the Honeywell T5 unit. Then it turned right on. Every other step was exactly as you described. Thank you for saving me hundreds of dollars. My local company wanted to charge $600 for 10 minutes of work.

[@HomeRepairHub]

Glad I could help. Thanks

[@LadyDJRaj]

Best Video!! No Music, No Jokes and No Nonsense!! Thanks! Keep it up!

[@aboutpar]

Yes!

[@mrharold5987]

Followed this video and was able to install both the thermostat and c-wire adapter with no problems.

[@sendo427]

Bro you made this look so much easier than other videos that I have watched that really don't explain everything well but you do explain everything and I appreciate that.

[@marlenortega-cruz766]

Thank you so much for your wonderful video, I was able to install my honeywell home thermostat with c wire adapter using your instructions!

[@HomeRepairHub]

Glad the video helped.

[@guccisasha]

Ty, I had a similar situation, and your video made the processing of adding the c-wire adapter go easy.

[@mikeinsugarland]

Awesome !! Yours video is a better tutorial then Honeywell own video. Thanks !!

[@HomeRepairHub]

Thanks. I appreciate the feedback.

[@UremicFrost]

thanks homie. bought the c wire adapter using your link too!

[@noomi]

Just wanted to thank you for this video. I had the same exact setup as you and this helped me install the c wire adapter for my new amazon thermostat. Thanks so much!!

[@soulepitomealfa1836]

Thank you I just completed the job on my off day👨🏾‍🔧

[@chengjiwei]

Installation starts at 2:15 for quick reference Relabel at 4:30 C wire adaptor at 7:20 Connect plate at 8:46

[@JRock-vf4fw]

Wow you made it so simple for me! Thank you!🎉

[@WakeUpAmerican000s]

The Honeywell "C-Wire adapter" helps in situations where your existing thermostat wire from the furnace has FOUR wires, but no C-wire. The adapter doubles up the cooling control and the fan control onto one (the yellow) wire so that you can use the green wire in your 4-wire cable as a "C-wire". If you only have two or three wires from furnace to thermostat, this accessory won't help you. You'll need to pull a new thermostat wire from furnace to thermostat if you want to use a smart thermostat that requires the C-wire for 24 volt power. That said, if you download the Honeywell T10 installation manual, there are wiring diagrams that show you how you can make a 3-wire cable from furnace to thermostat work by just connecting the green fan control wire from the "C" terminal on the furnace to the "C" connection on the thermostat. This disables manual fan control, but you can still use the features of the Honeywell T9 or T10 to control your furnace without having to string a fatter wire cable between furnace and thermostat.

[@magic4218]

Thank you for the nice summary of this

[@bvoghell88]

@@magic4218 Hello, just tried to turn heat on and nothing. Had to call Heating guy and he said I needed a common for the furnace to run. Is that what I needed?

[@magic4218]

@@bvoghell88 are you trying to install a smart thermostat?

[@Jellyballs]

You are a legend!! Thanks

[@-AnyWho]

i have a old 4 wire install setup. could i just replace 4 wire with 5 wire and replace my current blue with the yellow on both ends and then just use blue as the c wire and then ultimately skip the purchase of c wire kit? it just seems to me its cheaper for me to get 25' of 18/5 wire then it is to buy the c wire kit ... is there something i'm missing here or is the c wire kit just better in places where it would be tougher to replace stat wire?

[@filmguy5]

Thank you! I looked at a few other videos although yours perfectly explained everything I needed to do. Nice job!

[@djtimemasheen7585]

You saved the day!

[@lisasammons2343]

Thanks! I just bought the same thing. I will have to buy the adapter.

[@thulsimanickam2966]

Followed the instructions from this video and it worked out great. Thank you.

[@richca2004]

Do you have to change all Thermostats (I have 4 zones with 4 air handlers) in the house after installing the C Wire adapter? Are you installing the adapter at the furnace or the air handler?

[@bobbykimble6358]

Great vid thanks I got mine installed now

[@fftl1827]

Would my system would be "other" when it comes to determining my heating/cooling type. I have a dual fuel system but I do not see it in the instructions but I wanted to double check.

[@Lindon_Arelius]

Thank you for this video! I really like that it was straightforward and you didn't sell us anything or mess around at all. Quick question though, what do you do with the C-wire adapter box after you have connected all the wires? Do you just let it hangout? Do you attach it or tape it to the inside of your furnace unit on the sheet metal?

[@HomeRepairHub]

I had a shelf below the furnace that I could set it on. There should be a spot on the back that would allow you to hang it on a wall or something....or get some double sided tape

[@nhartman7]

Great video! Installation was a breeze!

[@SholomBeck]

If my hvac is only for cooling, so I only have R G Y can I use the adapter to get me the C-wire? Which means I dont have and dont need a W-wire.

[@gnom3_tb141]

How do you install the adapter if you have 2 R wires?

[@CleoCat75]

my old thermostat only used 4 wires, BUT there are 8 wires coming out of the wall, including the copper wire, but it's not working, so I heard that maybe it's not connected on the other end (since it wasn't needed by the old thermostat), so in that case, is it likely I just need to get into my attic, find the wire and connect the c-wire on the other end, and don't need an adapter? Thanks, nice viedo!

[@CleoCat75]

forgot to follow up on this. I did indeed go into my attic and hook up the extra wire since I had 8 available. However, that didn't fix it! Had an electrician come out, he took a look, said it all looked good. BUT, I didn't put the darn panel back on the unit and apparently it had a closed-panel circuit trigger, so if I had just screwed the panel back on it would have worked fine! so the guy charged me $94 to put a screw in basically, heh. ah well, lesson learned :).

[@LiveHappy76]

​@@CleoCat75 Yes, most modern HVAC equipment have spring-loaded front door/cover safety kill switches behind the door/cover that open and deenergize the control power and/or main power circuits as soon as the door/cover is opened or removed so that blowers won't turn on and burners won't ignite while someone's working inside the unit.

[@ikatsman]

good job scratching the side with the screwdriver twist...

[@katzenpapa]

If I install a smart thermostat upstairs and downstairs, can i use only one c-wire adaptor?

[@The11eleven]

Not if you have two furnaces that are connected to each thermostat independently.

[@bubbudubbu5515]

Hi, can i just use one c wire adapter to connect multiple smart thermostats , one for each floor in the house?

[@HomeRepairHub]

Does your furnace have zones?

[@bubbudubbu5515]

@@HomeRepairHub thanks for the response. I am guessing "yes, the 2 thermostats have different zones." One controls the temperature in 1st floor and 2nd controls 2nd floor. And they can operate independently.

[@LiveHappy76]

​@@bubbudubbu5515 Yes, you could land the two wires from each thermostat onto the one set of thermostat-side terminals of the adapter and have it work the same, if both thermostats control the same heating/cooling unit (I am guessing this is your setup). For whenever the upstairs/downstairs settings differ, whenever either thermostat's setting requires heating/cooling to operate, the system will operate even if the other thermostat's setting says it should be off. I'm an electrician.

[@joseRodriguez-pk9ld]

Hey bro is it bad if I put the red one on the RC place? I did that and everything is working fine

[@HomeRepairHub]

So usually if there is only one red wire it will be put on RC or RH, and then there is a jumper between RC and RH. If there are 2 red wires one goes to RH and one to the RC.

[@joseRodriguez-pk9ld]

@@HomeRepairHub I have 1 red wire but on the thing I have R and RC next to it

[@dennisc7706]

My old thermostat has the same 4 wires as what are shown in the video, plus there is a O/B wire. Can I use the same Honeywell adapter and connect the O/B wire to the O/B post on the Honeywell Wi-Fi thermostat? Thanks

[@HomeRepairHub]

So you have 5 wires correct? How many wires are required for the new thermostat? I think you only need 5 correct? You may not need a C-wire connector. kzbin.info/www/bejne/j3-biIuKmM9gepY

[@beasyphone]

I have a YC and a GF.. it's an 8 with the 4 still in the wall but none of them are beeping with my tester as common

[@HomeRepairHub]

I would suggest checking the board on the furnace.

[@beasyphone]

@@HomeRepairHub no board, I found 27 on (obviously) one of two from the outside unit, happened to be blue and yellow. Tapped( not literally) into the wire that fed INTO the transformer with one of the extra 4 in wall on top the blower, and ran WH-w, RV-R(not rc, and closed that switch off on tstat) , YC-Y, and my "new"(unused wore already fin loom) to C and called it a day. Got my constant(common) and alexa us happy, house is cool once more lol. Thanks guys+gals.

[@RonLego]

A little confused. What happened to the original labels that you put on the wires at the thermostat when the old one was removed. When you installed the new thermostat, the labels were different???

[@HomeRepairHub]

So if you watch from about minute 4 on, you will see that I put new labels on some of the wires. Hopefully that helps.

[@bungus3335]

What if your furnace isn't on the breaker?

[@Shalatee]

Can you use the adapter and would it still work if you have a c-wire that doesn't deliver 24v?

[@HomeRepairHub]

You may need a power adapter if it doesn't deliver the 24v. I don't know for sure though.

[@tonkeo9005]

How many blue wires can go into C terminal? My furnace already has a blue cable attached to the C terminal. Now I am afraid to attache another blue labeled C cable from the Honeywell C adapter😅. Could that blue cable is for another thermostat

[@douglastran1499]

What if the thermostat keeps powering off and on like flickering at the thermostat?

[@mummert1313]

i think this is because your furnace is doing 120v where as this adapter or the c-wire in general is looking for 24v. trying to confirm this myself

[@giancarlosp7]

Thank you!

[@kennethl5886]

Does this work if I have multiple zones? Great video!

[@HomeRepairHub]

I don't know the answer to that. I think it would depend on the system and how it is wired up.

[@kennethl5886]

@@HomeRepairHub Thanks for replying

[@dgibson8054]

I hooked everything up and now the outside unit keeps running even when off. I removed a jumper should I keep it on? Thanks

[@HomeRepairHub]

I would suggest putting the jumper back on. I apologize for the late response.

[@dennisgass1186]

Good video but doesn't indicate if the fan can be controlled separate from the heat/cooling

[@Kingdenniz518]

I followed the wiring. But when I finally plugged it in. The GUI didn’t turn on but the heater kicked in on its own Help

[@HomeRepairHub]

Is this a new thermostat? Does it run on batteries?

[@Kingdenniz518]

Yes. New. Same one you have there

[@LiveHappy76]

​@@Kingdenniz518 It could be that there is a splice in your wiring you don't know about, where wire colors were switched/not the same on both sides of the splice. Try swapping R and W at the furnace/A/C terminals. Either this or you didn't wire correctly somewhere.

[@jnis45]

How do you know which one is the thermostat wire at the furnance?

[@HomeRepairHub]

When you pull the old thermostat off you want to label your wires. Then on the furnace board it will be labeled with the same letters, otherwise the color of the wire will help identifying it at the furnace. Is that what you are asking?

[@1974chm]

Where do I connect the blue wire I also have yellow and ,, do I set up gas or electric my heater is gas and my ac is electric??

[@TheKingdomOrder]

I have a label on my thermostat that marked RC and RH. Could RC be my C wire connection?

[@HomeRepairHub]

Not sure, is there a spot for a C wire on the thermostat? When you go to your furnace control board you should be able to see what the other end is plugged into.

[@glensamels4964]

No. RC is not C.

[@LiveHappy76]

R = red wire; RH = red wire for heating control; RC = red wire for cooling control; obviously, any color of wire can actually be used for any connection, but red is conventional. C = common (the neutral/return wire path) and usually is blue from a non-battery-powered thermostat and white from an outside air conditioning condenser unit; again, colors may vary.

[@anevarez78]

Thanks for the video!

[@SinfulQueen13]

I’ve read if you remove the g wire and put it in the c slot that the fan won’t work by itself unless the ac or heater is on, is that the same with the adapter or will it work with the adapter?

[@stephenkristman5696]

Did you find an answer to this?

[@Future_memory]

Exactly what ive done on my amazon smart but i have no FAN. Heat and AC settings kick in but no FAN

[@Glorksnork]

My thermostat has a G but i don’t think it has a Y is that ok?

[@jimbauer5560]

What happens if we don’t have a “g” connector on the furnace

[@luxman9463]

Any reason you couldn’t install this adapter at/near the thermostat?

[@HomeRepairHub]

I am not aware of any specific reason. As long as all the wires are long enough I would think it would be fine.

[@josel.guerrero2658]

Can I jump the R to C on thermostat?

[@ARCamaro5]

Thanks

[@Vanellaflowers]

“My green wire is connected to G a blue wire to Y a cream wire connected to W and a red wire to R with a jumper to RC.My spare wire is yellow is this d C wire? I am starting to get the feeling that the blue wire connected to the Y is the actual C wire and that the thermostat was just connected wrong. Would this be correct? Everything has always seemed to work fine. I live in old apartments but use alexa and I really want to get a amazon thermostat.

[@HomeRepairHub]

you would need to look at the board on the furnace to verify. But yes in most cases the C wire is blue.

[@souravsen8861]

What do I give up if I use a C wire adaptor ?

[@glensamels4964]

Nothing. If you DON'T use an ADAPTER, then you have to give up discreet fan control. With an adapter, you don't have to give anything up.

[@LiveHappy76]

​@@glensamels4964 I wonder how that works...I'd like to see an internal wiring diagram of the adapter!

[@mjshuja1948]

I am SORRY,I KNOW A LOT ABOUT HONEYWELL THERMOSTAT,I JUST INSTALLED WIFI ONE,YOU JUST SAID ONE WIRE AVIBLE ( CONVERTER)THAT WIRE INTO C WIRE👍👍👍👍👍👍👍👍

[@MuradAkhad]

How to just power up thermostat and use it like a thermometer display

[@amandaasher4911]

So I just did this and now my ac system will not kick on at all. I tried putting everything back the way it was originally and still nothing. PLEASE HELP!!

[@HomeRepairHub]

new thermostat? Is there a battery in the thermostat? Are you seeing anything on the display of the thermostat?

[@amandaasher4911]

@@HomeRepairHub it was an Amazon smart thermostat. AC was operating until I tried to install the c wire adapter. After I installed the adapter there was no power to the thermostat and no air blowing from my system. So I reinstalled to the original thermostat and uninstalled the c wire adapter but still no air flow.

[@HomeRepairHub]

@@amandaasher4911 and still no power to the thermostat?

[@amandaasher4911]

@@HomeRepairHub I figured it out. It was just a blown fuse. Thank you so much for your quick reply.

[@powder877]

Good good

[@afaafa3679]

you don't need a c-wire adapter...those 2 other wires that are also connected to the board are C & RC wires & weren't connected to your old thermostat because wasn't needed...if you look inside the whole in drywall behind the thermostat they r most likely there! ... nice video!

[@ahyungrocks5509]

I watched this video a couple times. Saw bunch of wires getting connected and disconnected. Not hearing the explanation on what each wires are and how they should be re-routed.

[@HomeRepairHub]

I appreciate the feedback. What specifically can I help with? Are you using a C-wire adapter?

[@miss30427]

👩🏾‍🌾🍬Thank you for posting this installation tutorial.

[@alainazielinski]

Thank you! The written directions were stink.

[@SoCalBruce]

No A/C?

[@stevepatterson5086]

Looks that way. I followed his instructions and the thermostat wouldn't control the AC. Had to do a bit more research for what to do with the Y wire connector so the AC would work.

[@Kona297]

@@stevepatterson5086 Hi. Can you let us know what you ended up doing with the Y wire...adapter says to attach to the K at your new thermastat. I'm having the same issue. Fan blows, but AC unit does not come on. Thank you.

[@MrGixxer11]

Wow, totally fast forwarded past the important step of connecting the wires to the furnace control panel. ??

[@kimberlyescobar1013]

i don’t have a green wire but i have a yellow what do i do?

[@georgecunill2223]

The control Board of the furnace shows a C terminal but there is no wire connected to the existing Honeywell thermostat which has no C terminal. The R terminal of the furnace has 2 wires connected to the thermostat , one connects to the RC of the thermostat and the other connects to the R of the existing thermostat. The W, Y, and G terminals of the furnace are connected to the W, Y, and G terminals of the thermostat. The C of the furnace connects to the terminal of a Relay contactor. I bought a MOES smart wifi thermostat for the furnace and AC that requires de C cable. The Diagram of the thermostat requires a jumper from RC to Rh. The Diagram also shows the terminals W,Y, and G to be connected to the furnace and I should not have any problem with that. I am planning to connect the R terminal of the Furnace to the RC terminal of the thermostat with a jumper from RC to Rh. Remove the other connection that goes from R of the furnace to the Rh of the thermostat and use this cable to connect the C from the furnace to the C of the thermostat and would keep the existing connection from the C of the furnace going to the terminal of the Relay also located at the furnace. Do you think that this new wiring could work? Note: there is only one transformer at the Furnace

[@HomeRepairHub]

Without seeing the diagram for the new thermostat I don't know the answer to that. As long as you connect everything the way the diagram for the thermostat shows you should be alright. If you have an extra wire and you are sure it the same wire on both ends I don't see any reason you wouldn't be able to use it for the C connection. If you have some concerns you may want to take pictures and go to and HVAC store and see what they say or call in an HVAC tech to look at it. I am not an HVAC technician so I am not sure I would be able to help in this situation.

[@chrisao1987]

I was wondering what this was and don’t quite understand why you need it. You can pull another thermostat wire easily and in your air handler you have a C wire to the far right. That’s your common wire. Just get a new thermostat wire with a few extra wires and tape it to the existing in the house and pull it to your air handler and reconnect wires.

[@McDrunkerson]

Sorry, not a fan, no pun intended. If the wiring block on the air conditioner had a c terminal why would they just run a c wire? Mine has only a red green and white wires making this entire installation impossible. This was not clear enough when I bought this unit and now it's too late to return it, not happy with Honeywell at all.

[@tedlahm5740]

Sadly, poor explanation of C wire adapter. At the furnace, the second set of wires were labeled Magically. Also no explanation of how fan and heat are now one control and CAN NOT request fan only ?

[@mariemorgan]

If you mean the Honeywell c wire adapter wires those come prelabeled. So i guess that could be considered honeywell magic?