Great info! The “main” speaker obviously knows what he’s talking about! The camera guy really should be quiet and let the speaker finish. He’s rushing him. Switch places if you need to, but don’t talk on top of the speaker.

Excellent video! Definitely gave me a greater understanding on how the basic wiring of the system works as I prepare to embark on a diy thermostat replacement adventure. Thank you, guys!

Glad these guys had the answer I was looking for! The O/B solved my problem, the manual said nothing!

Thanks. This was a basic but clear and helpful video. I was swapping thermostats and the connections on the two were not the same, and this helped me get it correct.

I just wanted to say thank you for this video, it is a very good explanation of the thermostat wiring. I just purchased a home and am installing a new thermostat, this really helped. I just wish you were closer to Mississippi so I could hire you.

for the first time I understood..When you comparing with a car was BRILLIANT. the y is alway running the O determine if it is cool a heat.

Hello and thanks for the videos. I am replacing an old mercury based Dayton thermostat with a White Rodgers 1F78. It appears the wiring scheme is unorthodox for this old thermostat but it worked perfectly, I just wanted to convert to digital. Anyway, the blue wire was connected to R5, White wire to Y6 and Red wire to W4. I am trying to figure out which ports are equivalent on the 1F78 because it seems to simply stay on. I have heat only; a Weil-McLain boiler

Good video. This helped me clear up some confusion with my Honeywell RTH8500 and its separate "E" and "W2" wires from the old 7-wire bi-metal mercury switch thermostat. I have W2 running to Aux on the Honeywell terminal block and the system tested fine, just wanted to be sure.

you are the best, 2 hrs on the phone w/someone in India 2 min watching you. thanks dm

This is a good and helpful video, but I think on your large chart it would be better to show not only the Thermostat connections, but the connections on the furnace or AC (heat pump) unit that the thermostat is connecting to. Also for some archaic reason the industry continues to use the colors of wire as the recipe for hook up. In other words, a red wire is connect to "R" on the Thermostat and to the "R" terminal on the furnace control board. However you could actually use any color wire to connect "R" to "R". It would make a lot more sense to have "R - 24 volts" printed on the furnace board and more importantly in the manual or documentation. I've found the documentation included with a new Goodman furnace to be particularly pathetic in this regard. Another oddity if there weren't enough is "G" to stand for room air fan or Fan . "Y" for AC compressor. Who would have guessed? Why not "AC" for AC, and "F" for fan? On the control board and eeven inside the the thermostat it could be printed as "G - fan" Then there could be a note or sticker or printed into the plastic "Note large letters = traditional wire colors make sure the proper devices as specified are connected together regardless of actual wire color. Apparently a traditional simple thermostat had two terminals and a single insulated wire with individual red and white wires inside. "R" was meant to hook up to one side of a 24 volt transformer, and "W" (the white wire) was meant to go to one side of the gas valve with the other terminal of the gas valve connected to the transformer. When the thermostat closed, the circuit was completed and the gas would open, and the gas would be ignited by the pilot light. Perhaps all of this should be taught in Jr. High School, making American education more relevant and practical.

Any time you have wires you are not sure about trace it back to the other units , make sure you understand what colors are on what terminals. Because often if they are mismatched you clearly are going to have problems. Sounds like you need to trace it back to the root.

good video thanks. im an Electrician but ran in a few. i have a customer that wants to replace a programmable thermostat with a Horizontal non programmable thermostat. i havent even looked at the situation yet but its good to know what each one actually does instead of replacing wire for wire.

EXCELLENT! Cleared up a ton of questions.

Keep it simple stupid great job guys!!!!! Understanding makes it so much easier

Thanks! all i needed to know was what the other color for my AC unit was. one was on the 24v, which made sense but was having a hard time finding out where the other wire went to compete the circuit

thanks for the video, I have the L8148E, and I want to change my thermostat for the RTH6580WF. I only use the heat and my old thermostat works with two wires. where you should connect the wires for the other thermostat. Thanks

My thermostat for a system has a red white and green wire. My question would be, would green be placed in O or B to close the zone vavle

Great explanation through out especially about the jumper wire.

Could someone jumper W G and Y to make the themostat control the fan in both heating and cooling modes?

Thanks Great video!My tenant hooked up a thermostat without letting me know and I want to check if it is what I should do to correct it since I think there is an error. The thermostat is a Hunter 44272 that does combine Aux/E my unit is an old Trane (GE). X2 (emergency heat) is going to Aux/E on the thermostat and and W/Aux heat is going to a spot listed as blank in the thermostat diagram that is usually w for conventional heat contactor will my fear is this will activate the heating coils in heat mode no matter what. Should I disconnect w/aux wire from the blank spot (for heat pump) on the hunter thermostat wire nut it and leave the X2 (emergency heat wire connected to the Aux/E? Or should I add the w/aux wire to the Aux/E terminal on the thermostat and just wire nut the X2? or as you said in the video it doesn't hurt to jump should I just add X2 and w/Aux to the Aux/E on the thermostat? Thanks

Wasn't sure about this video at first but as I continued to watch it helped me a lot. The O/B section solved my problem.

Informative and entertaining at the same time. I clearly did not know what color wires served which function. There are several small colored wires coming out of the overall insulated wire. Wish Honeywell would have put together a "how to” video for the thermostat I just bought. Only one was of HW selling their products.

Great video! I have a honeywell three stage furnace. The old thermostat had "W3" but i bought an Emerson smart thermostat and it has a no W3 terminal, but does have a WE terminal. Do you figure it would be ok to just put the old W3 to the new WE terminal? I might be being overcautious, but figured it wouldn't hurt to ask.

C is common and that was hooked up to my old thermostat. Where would I put that on a honeywell RTH2510?

Excellent video. Didn’t get bored. Very well presented and understood. Good job!

Well done. Confirmed my recent hookup of a Honeywell unit. Thanks!

Just bought a new Honeywell thermostat looking at the old one i don't have a wire going in to C its say to put the G wire into C slot then to go to furnace and move the G wire to C and jump G to Y. when i look at the furnace there a wire going from Y to C (2 wires in the Y slot) not sure what to do

What if there's no wire attached to o or b on a thermostat?

I was trying to install a new 5 wires thermostat replacing an old 4 wires. I used extra wire as c wire but the furnace terminal board side already has a wires attached to it(C and Y), which runs to out side compressor unit. when I attached the new run c wire to this c terminal it is blowing out my 3 amp fuse. where should I connect the c wire of the new thermostat then?

Great video. However I believe and I could be wrong on this, but I'm sure many of the units I've operated functions as I describe. At about 3:40 talking about the Fan mode and System Mode, you stated if they system is in off mode then the fan will not operate, that the system is in complete off. I believe even if you place the System switch to off, you can still run the fan mode only. It is designed this way to allow the user to be sure that the System settings in heat or AC are not on and can only operate the fan only mode. Say you just want to move air in the house without having heat or AC.

what happens if you accidentally run the common wire from the air handler in to (B) in thermostat? is that bad? or will it just do nothing and not affect anything

hi, nice video. i want to install a nest. my old thermostat has the white wire and black wire connected to the same terminal "w." i was told that i couldn't do the same on the nest. so my question is why are the white and black wire comnected together on my pld thermostat...and if i install the nest how what terminals would the white and black go into. any help is appreciated.

Thank you, a great straight forward explanation of the basics.

My Goodman heat pump sometimes will turn the outside compressor unit on but fail to turn the air handler on and then it just runs and runs while the temperature in the house gets either really hot in the summer or really cold in the winter. I was told this could be a sequencer inside the air handler or it could be the thermostat which is not programmable but is a Janitrol with two mercury bulbs inside. If we turn the system off with a switch on the thermostat and then switch it back on later usually the fan will kick on and run fine for a while but then it will start acting up again. Does this sound like a bad thermostat or a sequencer inside the air handler? By the way thank you for helping me understand what the W & E screw terminals are for in my heat pump's thermostat.

Very clear concise information, in spite of the rocky start lol

very clear and precise instructions.

Are there HVAC systems that fill up all the holes in the thermostat?

I have two black wires plus a ground. What terminal does the ground go to? Also, is R positive and W negative? Thanks!

THANK YOU SO MUCH FOR THIS!!!! EXTREMELY HELPFUL!!! :) Great job explaining what all the letters represented.

Hi, and how to connect two thermostats in parallel?

THE FURNACE TURNS ON WHEN I RUN MY AC! HELP! ANY IDEAS? TROUBLESHOOTING?

Thanks for the break down of what the wires do. However, I have this one question. The orange wire at the Goodman Heat pump which is for the reversing valve, does not have a mating orange wire to be connected in the 5 wire harness arriving from the Heat Exchanger. How do I apply control voltage to the reversing valve?

Thanks you really help me out. I was having trouble connecting my new thermostat and the OB was the problem when I switched it to heat pump it came on correctly. Thanks again.

If heat pump outside unit is run in reverse mode on cool what wires do I swap and where at i know It's the blue wire and orange wire just not where at to do it

My existing system is Gas Furnace and single AC unit. My existing thermostat has C,G,W,Y and R (no jumper). The new Thermostat has the choice of RC or RH with a jumper. (no R). Question: Which terminal do I place the existing "R" wire to? RC or RH? Do I leave the jumper in or remove?

Very good, Thank You for taking the time.....

I want to replace a trane ay28x105 thermostat with a ecobee 3 the inside label says 30 volts on the old thermostat so to install the new one will I need a transformer or is the label wrong

Great Video! thanks guys. Best explanation I have seen.

Great video. Love your blue collar NC accent - it let me know that you were the guy in the know!

What if there is no orange wire to go into o/b?

Question , How do I make the system with Honeywell T5 thermostat activate the heater?

Thanks man. Great video. Very useful

An old humidity control as well I installed a new digital AC but I don't know what the humidity control how to remove it what do I put those two wires the ride and the Y

So I put in a thermostat for my mom... Her a/c was acting up and this was an easy fix to try as settings on it were changing when you didn't touch the buttons... I labeled the wires as I pulled off the old thermostat... Holes in the new thermostat exactly the same as the old one... Matching the letters to the now lettered wires... Set up the thermostat and turned it to cool... The heat ran! Mind you I hooked the new thermostat up identical... From what I read maybe an electrical problem actually IN the new thermostat?

I have a Emerson 1F83C-11NP when the heat kicks off it waits about a minute and kicks on just with cool air and runs 3-5 more minuets.Please need help might be a defected thermostat

I have an old Snyder General but my wiring is different to that of what should be standard. I have X, R, B/C, G, W. I'm trying to connect Honeywell Wifi thermostat. What does the X and B/C really mean? I can email a picture. There are 4 wires coming from my old thermostat (no common).

Excellent explanation it helped us fix our problem!!!

Good video, comprehensive, easy to understand. Well done

Great video. I have a 2H/1C system that is NOT a heat pump but I am having a hard time finding a thermostat that will reliably work with the system. Biggest issue with the universal tstats is that I'm trying to determine which wire will control the 2nd stage of the gas valve. Any input is much appreciated. Thanks!

Thanks, Ryan. Awesome!

Is a wire required in both Rc and C? My installation only had one wire and when I changed it from Rc to C it didn't say I was at 24 av.

some stats have one terminal for o/b and a switch in side that you flip.

Hi Sir, my Emerson programmable thermostat 1F78 have green wire and a small screw but doesn’t have slot/hole to screw in. The available terminals that have slots/holes are O & B. Where should I connect the G wire?

What if i dont have a orange wire just read and the person who hooked up my thermostat put the red in the o place ?

I have a new T/S hooked up like this with one exception , we have the white wire on w2 which is how the original was hooked up however the heat pump is not working in heat mode,do i need to put the white wire on W1 and if so what makes the stripes EH come on? I'm being told to put a jumper from Y to W1 , which way is right (Trane unit HP)

Can I wire my thermostat to run heat only? I was going to run power for AC in the spring. (heat pump)

Should you have a wire to each terminal? I only have heat, no central air, and only have 2 wires coming out of the wall.

Very helpful video. Thanks

Very helpful. Thanks! thumbed up!

I enjoyed your video. I have two Robert Shaw thermostats....9600 and 9610. I have gas/electric units. One thermo will activate a/c-or heat unit by adjusting temperature one degree at a time....normal I think. The other termo will only a activate heat or a/c when you adjust "two degrees"....very frustrating. Do you think this an improperly wired problem or something else? Can you help.lblvnv1 second agoI enjoyed your video. I have two Robert Shaw thermostats....9600 and 9610. I have gas/electric units. One thermo will activate a/c-or heat unit by adjusting temperature one degree at a time....normal I think. The other termo will only a activate heat or a/c when you adjust "two degrees"....very frustrating. Do you think this an improperly wired problem or something else? Can you help.

I know this is going to sound stupid but I got mad and smashed the thermostat in my hallway I went out and picked up a new one I put the white to W the red R the blue to b the green to G and the yellow to y now when I turn on the heat the outside unit wants to run and no it's not a heat pump but when I kick it to AC the outside unit does not come on just wondering if you could give me any idea what could be wrong

nice, clear explanation.

Can yall help me out? I am 68 and on Social Security so I am trying to change my Themostat. It is a 2 wire one in a mobile home. It has the heat/off/cool switch on the unit itself in the closet.. so the heat and the air both work off of these 2 wires. . The letters on the Intertherm Ultraflex Relay Control board are an (A) and a (W) for the T- Stat.. The control board is Number 901648. Anyway, I tried to remember which of these wires hooked to the expanding coil on the old thermostat and I forgot.and it was not lettered either.. I am putting the Honeywell CT-30 manual thermostat up, it is a 2 wire also.. It has the letters (R) and (W) on the thermostat. I see the one marked (R) is controlling the expanding coil, I believe, looks like it anyway... Could you please tell me which wire from the relay control board I should hook to the Coil? Right now I have it hooked up as the (A) from the relay board to the RED on the thermostat and the (W) from the board running to the (W) on the thermostat. Is the correct or is it backwards? It is saying it is 80 degrees in here this way and I know it is not that hot in here right now at 2:00 am in the morning. It come on and shuts off I guess as it should but like I said, I know it is not 80 degrees in here now which the thermostat says it is. Any help will be greatly appreciated....If you need any further info. please let me know. Thank you very much for what you do... Roger Shingleton, Wilson, N.C.

Is the E same as w1

Great video

Awesome instruction.

Decided to watch this video as an afterthought/follow up .. well, I guessed thru it, and got it right .. thx 4 posting this …

Not sure why there are so many dislikes. Great explanation - thanks!

I bought a new thermostat and went to install it, but there was no "C" terminal but I have a common (blue) wire. I dont know where to put my common wire, and I can't get the thermostat to run. I am trying to run heat and air if that helps. If anyone knows anything please help me.

If there's one term o/b how do u change modes

When I set up the thermostat to heat my house, it just activates the fan but wt does not give me hot air, just room temperature air. I wanted to upgrade the thermostat and I bought and installed the T5 thermostat. The AC works by the way.

Great info. Thank you

Hi I need help with a 1F78 thermostat. I need a diagram of the 3 wires on the front, are all 3 supposed to be hooked up?

I'm installing a new thermostat. 3 wires coming out of the wall are red, white and green. The terminals on the new thermostat are red, white and yellow. What should i do with my green wire? Hook it to the yellow? Thanks

I have an issue. I tried replacing an old analog thermostat (2 wired), with a newer programmable Honeywell thermostat on an old Coleman presidential 2 on my mobile home. Once I switched the power on on the furnace, the ac started blowing. No matter what function I changed on the new thermostat the ac would not turn off. Any suggestions?

I agree....the cameraman really detracts from the speaker

Hook up my wiring seems my common is blowing the 5 amp fuse when i switch it into heat mode. Why i dont see any bad wiring

Hi, I was wondering if you could tell me what color wire goes to the letter C here in Florida. Thank you

How do u run the thermostat wire on a heat pump does it go from the thermostat to the inside unit then from there to the outside unit or what need help know how to hook up just not sure how to run it

Thanks Ryan

Wonderful video thanks

Awesome video.. GUys do you have codes for honeywell thermostats? mine is displaying E2. its an old unit from 2002 T8411R

My wire connection has a white terminal it leaves the white off I put on the Green and the yellow and there's a jumper between the red and the red c

90% of the issues we've seen in the field with wrong installations Are following colors. W, to white , Y, to yellow G to green R,to red which is correct until Blue goes to o/ b which is incorrect (C,to Blue) most customers see fuses blowing while attempting to operate the heat, months later. The r jumper you mentioned is if your thermostat controls a separate unit for heat vs cooling like space board heaters and a Ac or swamp coolers. If there is a jumper from rc/rh it stays inplace if not always go to Rc/R with the Red Nice video

Im stumped. Trying to install a smart tstat that requires a C wire. Ive got 29V from R to Y, G, O at my tstat. My R to C has 29v at the heat pump unit. I ran a blue wire from the C terminal at the heat pump unit down to the tstat. The other end of the same blue wire that reads 29v at the heat pump only reads 16 to 17v at the tstat end of the wire. WTF? What would cause the wire to lose 10 Volts? Its no longer than 7 feet of length (at least that's the physical distance from the tstat to the bryant heat pump unit on the roof. The connection to the C term is solid. There is continuity. Somehow, as that blue wire is snaking through the drywall down to the tstat it is losing 10 volts. I can't explain that. I tried a different wire, and same result. 17 volts. Makes no sense.

I don't have a heat pump but I have aot condition when heat is on but not when cool is on. I think my blue needs to be in O. Not. B. THANKS

I have a old thermostat with a blue wire hooked up to x the new thermostat don't have an x termial

I Have W..... Y..... G..... Rc..... and C wires from my wall but the new thermostat i got doesnt have Rc .......its just R...is it possible to connect Rc wire from my wall to R to my new thermostat?????

I am confused. I have a basic honeywell my white wire is in w blue in the b slot yellow in y green in g and red in r and a jumper between r and rc yet my furnace fan won't turn off ever even when the whole unit is off and my ac kicks on only when it's switched to heat. What am I doing wrong

i have abcd green,black,white,red four wire how to installed nest 3rd genration thermostat