Connecting Nest Thermostat To A Boiler 

Recently installed the Amazon smart Thermostat on a heat only boiler system with 2 wires. Between this, and your other video on installing the C-Wire it, was a piece of cake. Coffee on the way! Thanks

Thank you much for your time and expertise. Dead on. I was having an issue with the heat end as it was short cycling. Wired common directly to boiler and boiler fired up and stood on. Thanks again.

Beautiful love the simplicity of this video. Great Explanation 👍

Perfect!!! I’m one of them with a “dual fuel” system ( Boiler & Forced Air). Thank You!!!

Informative and much appreciated. Thank you so much!

The standard 2 wire system is not working with my Nest and I think it relates to what you mentioned at 7:20 where the Nest is not getting enough power from the boiler. 🤕 Thanks for posting this video, and others!

Super helpful and informative! Thanks!

Hey there James, great videos, very informative for sure. I'm having issues with one of my 4 nests. My setup is stand alone 5 zone boiler with completely separate AC system. AC worked flawless all summer using nest unit. Now heating season is upon us and issues are cropping up. Heat works intermittently on the same nest used for AC. The other 3 nests are fine and no issues. All are connected to the same boiler. I've got 3 extra wires going to the problematic nest to the boiler. Today I hooked up a 24v 100ma transformer to 2 of those spare wires and then connected them to the C and RH terminals on the base plate. Of course I disconnected the red wire that was in the RH. This prompts a E79 message no power to C detected. I can message 24v on those spare wires ? Any words of advice would be appreciated. TIA

Awesome instructional video

Awesome job man. That was very informative

We purchased a home in late 2018 that has a NEST (3rd Gen) thermostat in it. We have a simple Propane Boiler, so the base on our NEST thermostat has only TWO leads connected to it. The first (white) lead is presently connected to the W1 connector, while the second (red) lead is connected to the RH connector. There is no (zero) C lead connection to our NEST base. Our simple propane-fired hydronic heating worked fine for our first two winters in the new house, but during this summer, we noticed that the 3rd gen NEST thermostat began requiring a manual recharge (via an older Android type charging transformer/cord). After the NEST thermostat is recharged, it works fine -- for a couple of hours. After that, the red indicator blinks and it requires another recharge to function normally. My initial thought was that the battery is defective, but this video -- and its explanation of the "C" lead -- has me wondering. Is it possible that the battery power (alone) was sufficient for a few years and now our NEST thermostat requires a constant charge via a "C" lead: like the AC-powered version you featured in one of your other fine videos? Regardless, I find it hard to believe that a 3rg gen NEST thermostat like ours would have a defective battery and/or charging circuit. Why? Because, and I'm assuming here, the 3rd gen version isn't very old?

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

Great info, but can you tell me how to connect the nest to an aqua stat for infloor radiant heat?

Good video. Pretty straight forward. I have my nest 3rd gen. connected to a 2 wire heating only. It worked but sometimes it gave me an error E75 no heating or cooling wire but the heating was running. The diagram shows that W wire is not connected. A bit confusing why. I tested the voltage of the 2 wires and I got 16 volts. Any thought?

Nice very straight forward.

Great video!

Thank you!

This is great video, can you expand on this with a heat pump/ac plus boiler That’s what I have

Do you need to tie in your Common off of the AC terminals to the thermostat as well if extra power is needed to the thermostat? Or is just that one common from the boiler good enough?

Would you make a video about how to wire a combo water heater to thermostat? Thank you

What if you don’t have a c terminal at the furnace? I have a green end cut at the furnace and thermostat not doing anything. Can I use them to get my voltage?

I have two thermostats. One for propane, I upgraded it to a nest no issues works great. Got a second nest to upgrade my thermostat that's for my wood boiler and I can't get it's temp to report accurately and when I turn the heat up high enough to kick on the furnace the furnace repeatedly turn on and off. There's only two wires, red and white, and they are hooked up to R and W1. Any idea how to fix it?

11:00 my nest board only has an IR can I hook the red from the boiler and the red from the air conditioner to the R terminal?

Hi , need help Trying to setup nest 3rd gen , to a fire place , 2wire , Its wrong work right now , had a old mercury thermostat before

Can you help me with wiring for a Vokera Easi Heat 25 and Nest?

Can this be done with a Nest E? Thanks in advance for your help!

So I need the 24v transformer for my boiler. Your other video said to leave the wire from R loose and hook the transformer up to C and R. Is this correct? Or does the boiler wire and second transformer wire share the R terminal

I have a 2 wire system. W and R (RH and RC jumpered). All my thermostat does for heat is open a valve in the basement that allowed hit water to flow to radiators. I also have central air that it kicks in when the thermostat is set to cooling. Will those 2 nest thermostats work for me?

Hey James, How can i wired Nest E with Honeywell Aquastat Relay and TT terminals

is new nest compatible with boiler system ? new nest only has r. I used power connector not getting heat.

I have had a gen 3 running with two wires but it stopped working two day ago went and got anew gen 3but the same thing happened also when I took the unit off the base the boiler kept working working the unit said no power to the RH wire, it was weird W1 and RH ?????

How do I wire for a boiler and a heat pump system. I want to just use my boiler for heat.

I have a hot water boiler with 3 old thermostats that do not require a C wire. I want to upgrade to the nest which requires a C-wire. My transformer on the furnace has 4 zones\terminals. One for my hot water and three for my thermostats. Luckily all of the three thermostat wires have a bent over unused wire that can be used for my C-wire. Question I have only 2 common terminals on the bioler and need to connect three C-wires from the thermostats. Can I connect two of the thermostat C-wires to one of the Common terminals on the boiler? Thanks Dave

Hey I have a separate AC and heater. The AC is connected as you mentioned in your video to Y1, G (fan) and the RC. My heating wires are connected to the W1, C and RH. But the nest gives me a constant delayed start and does not turn on my heat. Can you please help me solve this? I can give you my contact information or vice versus if needed? Thank you!

I am replacing my honeywell thermostat with nest. But nest requires a c wire. When I remove the old thermostat it is connected on R and W wire. There are 2 extra wires sitting in the box (not connected). So I went to boiler and see that 3 wires connected to the zone terminal. I am wondering if the 3rd wire is a C wire? Any suggestions?

Can I put my 2 leads with a 24v transformer into C and R? My 2020 Nest doesn't have Rh or Rc.

Hello I only have W and R terminal in the boiler how I can add the C wire my thermostat giving me error N260 ? Please advice And can I make a jumper from from the R wire to the C ?

I have a thermostat with 2 wires connected, the R and W wire, however there are 3 other wires not used. Two of the 3 wires provides 24 volts when I tested it. Do I need a C wire? It's a boiler only setup. Can this work if I connect the 2 two wires to match the color on the nest thermostat?

I have a boiler system which I'd supposed to be high efficiency it heats the water to my house plus provides heat and had 3 wires which looked like w, r, y going to a Honeywell thermostat with a jumper to the c I put the wires in my nest 3rd gen and it said no power to the y ,I have a picture of the wires before I unhooked them if there is a way to get that to you

If I shut off the circulation pump (with a switch) in the summer, will the Nest still receive power to keep the battery charged and keep it online?

My ADT installer was saying I need a heat link? Anyone know where to get one of those?

Can is connect a simple 220v heater fan to nest , just to switch it on/off ?

Emile, hi James I have a hot water boiler system and a central air conditioning and air handler.I'm installing the new Google thermostat when I took plate off of old stat it had FC and rh wire.but in new nest only had one port for r wire. I did hook one up to run boiler with c adapter which works fine. Can I hook one up with one r port. Thanks!

I have a nest on unit that has ac and hot water heat. Either the heat won't work or the battery won't charge. If I hook up the common the battery charges but the heat doesn't work. If unhook the common the heat works but the battery goes dead. What do I do?

Will the nest go into error/no power mode if my furnace has gone into a hard lockout?

Thanks for the great info - made my install much clearer. I connected Y / G / Rc on the AC side, and Rh / W on the boiler side. I powered on the AC & that works. But when I powered on the boiler, the boiler began making a lot of loud clicking noises (not normal). There is 24V from the boiler; I removed the Nest, connected the R & W boiler wires, and turned the boiler on - it started right up. Any idea why my boiler is freaking out when connected to the Nest?

I have a one-pipe steam heating system & a new AC unit that I just installed. I tried to install a nest & it blew a fuse on the AC. Needless to say, I was disappointed - I contacted Nest & they told me it was not compatible, but your video seems to indicate that it should have worked. I'm not sure what I did wrong- I thought it was a Common Wire problem. Do you think I can try to install it without a Common Wire? Do you have any advise?

I don't see the video on adding the c wire. I have a two wire system.

Thanks for the video! i have a conventional fan coil 220 volt with three speed fan for heating and cooling could you please say me how should do wiring ( i have 6 wire- 1 phase 2-nuetral 3- earth 4- fan 9(low speed) 5- fan (medium speed) 6-fan (high speed), Thanks again.

Thanks man

I’m planning on putting a heat pump in my parents house and they currently have a radiator system that heats the house, can I put them together on a nest like this?

My nest all of the sudden goes into delay after running for 10-15min. I checked the power and it says I’m getting in 3.8 voc 38 and 9.2. So it’s powering and this is the first time it started doing this. Any suggestions? Kris

Will all Nest Models work with a Boiler? Are there Nest models that will NOT work with a Boiler? Thanks for this and all your other vides! Awesome information!

Hi, Very informative, however, it didn't quite hit my issue. I have a Propane boiler. My thermostat had 3 wires, R/W/G. I connected the red & white as you show. The Green I connected to G. My boiler also serves my Hot water heater. After a couple of days, (summer so heat is off, Up north so no AC) the Nest began telling me I had no power to my RH terminal. Now I have no hot water, nor heat. The Green wire my be tripping me up. Should that go to the * terminal?

My boiler does not have a c wire and currently is wired to a 3 zone heat only system switch which also does not have a c wire hook up. Hiw do I find a common

How do I wire my boiler AND central air to the same nest?

Thanks for the video! I have an old wood boiler adapted to work with a Blaze Harmony XS26 pellet burner, and I would like to use Nest Thermostat to control it. The pellet burner doesn't support OpenTherm nor the Nest Thermostat itself, it only supports regular on/off thermostats. Can I use it as On/Off Thermostat and get the advantage of other features it has like Google assistant enabled or Home/Away modes? In case it's possible, the control panel has a 2 wires connection for room thermostat, but it doesn't deliver any power (works with 12V), so Net would need to be powered somehow else. The other option I saw is the use of Heat Link which is sold in Europe with the Nest Thermostat, what do you think about that? Thanks again.

This is very helpful but I am still lost trying to figure out a hydronic switching relay + AC system

with the duel fuel system separate heating(hydronic boiler) & cooling (air handler ) do I need separate rc and rh or do they jump internally with the newer nest learning thermostat

This is exactly the video Ive been looking for . One question though, My AC unit has 4 cables. Red, Yellow, Green and Blue. When I short Red and yellow I can hear the coolant releasing but its not blowing air. When I short Red and Green. The fan kicks on but no Coolant so it doesnt get cold. Can I short all 3 cables together to make it work? And if this works, does that mean I have to connect 3 wires to the Nest? Also what does the Blue wire typically do?

Nest with boiler situation just as you described. Two wires only (red and white) which I connected to the Rh and W ports on the Nest thermostat. The heat comes on but it won’t come off again no matter how cold I set the temperature. Only way is to shut off boiler manually by killing its power. Not sure how to fix this.

How would you put an adapter on this

I want to replace an old manual thermostat with a Smart Thermo like Nest or EcoBee. My boiler is a Triangle Tube Prestige Solo 110. The information I have is that it uses dry-contact T-T terminals, which are wired to the W and RH terminals of the old thermostat. There is NO access to the hole behind the thermostat to pull a third wire for the C-Wire. It seems I need to use something like the Fast-Stat between the boiler and the thermostat. May I ask you to cover that in a video? Particularly from the Triangle Tube Prestige Solo 110 perspective of wiring. Thank you.

My AC has two thermostats one upstairs with Rc, G, and Y and one downstairs with R, W. What would be a thermostat that works with this kind of system? Do I need a daughter/slave (no idea what its called) thermostat for the downstairs?

How do we get you to answer my freind. Nest is horrible. The have a person with a laptop reading off questions.

Hello, my problem when I put the oil heat burner on the fan start running nonstop because I have also Central air conditioning, can you help me thank you

I m in NJ. I have a simple boiler baseboard HW. My thermostats were all either basic which broke the continuity to turn heat off or on then had AA battery thermostats for day and hour timing on/off. Two wires one red one white, no other wires coming from the heater room on the 1st floor I have the nest Generation 3. I had to take it off every day to charge it which gets old especially if I forget. I installed a bo

Hi James. Im trying to install the newest nest thermostat to 2 wire boiler. I want to install a c wire but my terminals are not r w and c. I need to know where the c wire would be tied into.

Nice video. I have 2 Google nest E. My system is hydro heat. A boiler and two air handler (1st and 2nd floor), and 2 compressors. The air handlers do not turn on automatically when the boiler kicks in with temperature drop. I have to manually run the fan. Any help?

I have a boiler system but my nest Thermostat keeps telling me I need to connect the C Wire, I need help to fix this issue.

I could use your help. So I have a nest e and was attempting replace my 1st fl thermostat with my nest e. There is no central air just heat (not oil) i hit a brick wall because i realize that the wiring is thicker and i can't connect it to the nest when I'm trying to place them in the hole.... what can I do? I haven't tried replacing my 2nd fl thermostat yet because of this issue. Any advise is deeply appreciated. I was trying to connect these this weekend while I have the time.

What can I do if I have a 24v boiler system with no C terminal and I am getting a notice on from my nest to connect the c wire to avoid power issues?

Your videos are super helpful! I have been watching a few in an attempt to figure out why my Nest Thermostat (Gen 3) is not working correctly with my Navien Combi-Boiler. I recently upgraded to a Nest router from an older thermostat that only had an Rh, W, and Rh to Rc jumper wire. I took out the jumper since Nest said it wasn't required and then I put the Rh into the Rh slot and the W into the W1 slot. When I connected everything back up, I noticed that my heat was constantly on even though I turned it off at the thermostat and also turned the set temp way down, so it should have turned off. There were no error messages on the Nest either. To no avail, I could not get the heat to turn off and it was getting hot in the house, so I switched back to my old thermostat. Do you by chance have any suggestions?

If I have a regular heat system base board boiler and have two wires where do I connect them to on the Nest thermostat?

Thanks for the video , isn't the C terminal usually connect at the air handler ?

I have a gas boiler running hot water baseboard system (from 1988). I installed Nest thermostat with 2 wires (Red and White) but my heating system was shutting down frequently. Technician came and said NEST is not compatible so have to switch back to manual thermostat. Is there a way I can do it myself. I dont have C wire and Nest is going out of power frequently. Please help.

what if I have a Nest Thermostat (1st gen - the one that looks like a mirror), no AC and just a boiler that only has R and W wires, is the C wire a must? or can I just connect W to W and R to R?

So I have a separate AC air handler and a oil boiler burner system. They are currently being controlled by separate thermostats. Are you saying I could integrate all the wiring on a single thermostat that could control both AC and heat? I was under the impression it wouldn't work because the power had to be on the same circuit as boiler circuits, that's why the installer put them separate.

Can I call you or FaceTime you brother for a quick trouble shoot. I just moved into my first home and it had a nest thermostat installed already and a Navien tankless boiler . But I’m not getting any heat . W1 and power are connected but still no heat. I’m even getting notifications from nest saying the temperature in the house went down when heat was on. Please let me know. I can even zelle you for your time . Thanks

My boiler transformer has no c wire, it's only two terminals. How do I use a c wire?

I have a hot water boiler and A/C in my home, I got the new NEST with the mirror finish. It keeps telling me can't detect white wire. I do not have a C wire. I looked at my boiler, and there is no C wire connection ! I'm lost !

what if i have a boiler for radiant flooring heat and Forced Heat as well as AC and humidifier ? currently i have 2 thermostats one for the Furnace and AC and than the other one for the radiant floor heat

But boiler I have only has a two screw connection so where does C go? Guess change the block?

Can you a boiler with a gas backup?

Question I have 2 wire boiler. With noterminal only have 2 wires from my boiler that connect to red and white

I have a 3 zone boiler. I'm trying to install a Nest E by replacing the old three wire White - Rogers thermostat. (W, R, and Y) When my boiler is not running, I have no power going to my Nest E thermostat. As soon as my boiler turns on to supply heat, my Nest E works. So I believe I need to hook up a common wire. On the Nest E base I'm using the Y1, R and W1. How do I hook up a common wire to supply power to the nest 24/7? Since I have an air handler, my A/C thermostat on the other side of the house, so I cant steal power from it. Can I just buy a 24v transformer and add power to the base? Thank you.

Boilers have T T terminals, how to get the common?

What do you do if you have an extra wires connect to see but at the boiler there's no c-terminal?

Ok so I am so confused, I have watched all the videos and none describe what I have. I have a AC/heatpump outside. But I also have a furnace downstairs that runs off oil. I only have 1 R wire on my old thermostat. I have Y O G R C W E Those are my old thermostat wiring. In the nest, do I hook the E to the star and the W to the W1 on the nest to still have both my heatpump and my furnace as emergency after if gets below 35 degrees outside? Because right now, my thermostat runs off heatpump 35 and up and the oil kicks on at 35 and below.

Great videos.. I've watched pretty much all your videos. I wired my nest 3rd gen 2 wire system about a 1½ year ago everything worked great. I woke up today the nest was off. So I ran a 24 volt hot to RH and neutral to C and w1 to control the boiler. But now the nest temp raised from 72 to 78 without the heat coming on.. ANY HELP WOULDBE APPRECIATED

When I have a zoned boiler, do all three zones need a nest?

I'd love to see a video on how to use Nest with an HRV.

Why would my fuel oil boiler for hot water base heat keep running well past the set temperature. Example nest set to 62* and actual temp is reading 77* and heat is still running?

If my boiler does not have a C terminal, may I use the C from the AC instead?

I have the same problem as Sai G. it is not recognizing the RH wire. It is also turning on the electric heat portion of the A/C unit rather than the boiler system. I did free lance and add the green wire to the green terminal. I would like to have fan control.

3 cables coming from ac, how Can I connect it

You are fantastic. So Now I subscribe

I have an air and a boiler 5 wires but a nest with 6 ports no rn and google is absolutely no help

What if it's just not recognizing the rh wire?

How to hook up with only 4 wires