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The Nest is a programmable, internet-enabled thermostat

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2 humidistats for 1 humidifier

I have two zones in my house with a damper system and want to move away from using my humidistat to control the solonoid valve on my humidifier and instead use my Nest thermostats. My zone control ...
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One of two Nest Thermostats won't run Fan Only, fan runs with heat though

We've got two Nest Learning Thermostats (3rd Gen) running two separate heating and cooling units in an office. They both work fine for heating and cooling, with one exception: one unit will not turn ...
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Add “C” wire to NEST

I have a NEST thermostat. My heating and cooling system is in the attic.I need to add a "C" wire to the control board, but I can't find out where I need to open the unit in the attic to see where the ...
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Nest Thermostats: Balancing temperatures between zones

So, I'm wondering if there's a way that I can program my Nest thermostats to help moderate temperature disparities between my first and second floors. Here's the situation: I have forced air from a ...
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Can I use a nest thermostat for two heating sources (Furnace and electric floor heating)

Current situation: My home is currently heated with central air. Not my first choice, but that's what I have. I have brand new 98% efficient modulating furnace controlled by a Nest thermostat(no AC)...
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Help with a Nest E install on a old HVAC system

Hello I am trying to replace this thermostat with a Nest E but this has proven more complicated than I thought: I plugged all the cables to the nest adapter and figured that the blue wire which wasn'...
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Hookup Nest Themostat & Heatlink

I'm in the UK and trying to install a Nest Thermostat & Heatlink at home to control my hot-water and central heating and I'm having a few issues working out how my existing setup works so I can ...
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HVAC: Nest - Yet another 'C' wire question

I have a dual transformer system. At the AC/Blower unit, there are 'R_c', 'Y' and 'G' wires; there's 0VAC between the 'Y' and 'G' wires, and each shows 27VAC to the 'R_c' wire. At the boiler, there ...
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Nest Thermostat E Wiring Question

all, I wanted to get a Nets Thermostat E, but my current thermostat doesn't have a C wire. From what I read online, it's better to use a C wire, so I was considering adding a Venstar Acc0410 adapter....
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nest e74 code but its just heat no air

i installed the nest thermostat as instruction say i get the e74 code i checked fuse.turned power off an on now what is happening is when i attach the thermostat tothe base my relays flash quickly ...
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Secondary C Terminal on Furnace Circuit Board?

I was trying to install an Ecobee thermostat, and there was no C wire installed. When I went to install the power extender kit, I saw the standard C wire terminal was broken out of the black plastic ...
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697 views

Nest Hello Has Power but Doesn't (Often) Ring Indoor Chime?

I recently installed a Nest Hello doorbell and have run into an issue where the interior chime almost never rings. I say almost because exactly once in all my testing did it ring on the interior. I ...
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68 views

More wires than Nest needs

I had an old thermostat with wiring as below image: I wired Air Handler Trane (Model# TWE037E13FB2) in the attic just like it was before: Here is a wiring diagram of Air Handler: However, my Nest ...
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Replace thermostat wiring from my Carrier Weathermaker 8000 to my Nest thermostat

I'd like to replace the wiring from my Carrier Weathermaker 8000 to my thermostat to add a C wire. I assume I need to turn off the Carrier first, but there is no power switch that I can see on the ...
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45 views

Loud noise from outdoor unit several seconds after AC turns off

I haven't been able to find anyone online with quite this issue... I have a Carrier heat pump system, and through the winter it would often make that torpedo noise when heating the house (I later ...
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Is the PY4G HVAC unit compatible with Nest Thermostat?

I recently bought a Nest Thermostat and I've had nothing but trouble with it. The main symptom is the fan and the AC compressor won't run at the same time. Power only comes through the green wire, not ...
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Custom HVAC control

I currently have a Nest controlling my LP furnace. I'm getting an evaporative cooler installed and I'd like to also control it with my Nest. This post gave me a good starting point, but I'd like to ...
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Can I pull a common wire off an evaporative cooler transformer relay?

I have a Nest thermostat currently controlling a LP furnace. The old thermostat didn't have a common wire connected, but there was a an extra wire in the bundle and a common terminal on the furnace ...
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Try to rewire Nest and Furnace but Y is not used on Furnace

I installed a Nest at home and it worked OK. Recently, I noticed there was a power issue. Google and others suggested adding a power supply by using the existing G wire because there are only 4 wires. ...
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96 views

Another “How do I add ”c" wire to boiler for Nest

I have tried searching this forum and others, but I could not find anyone with a situation like mine. I thought it better to ask here, rather than damage something. I have a Lennox wall mounted ...
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758 views

Nest Protect Expiration Date

I just bought a set of Nest Protects and after opening the first one I noticed that its manufacture date was almost a year ago and that the expiration date was 10 years from the manufacture date, not ...
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Can the wire from the y terminal on thermostat be connected to the c terminal on heater board as pictures show?

My nest was installed with no c wire and it lost power. At this point the tech looked at the wiring diagram in a/c unit outside but I do not know what he did. A/c worked but later nest had no power. I ...
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Installed NEST thermostat heat works fine, AC compressor comes on but no fan on AC unit

I installed a new NEST thermostat last fall so only used it for heat so far. When I went to turn on AC, compressor came on but AC unit fan didn't. AC worked fine last year. Could this be a NEST ...
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71 views

Where to install C wire?

I need to run new thermostat wire since I don't have a C wire to power my smart thermostat, but need some guidance on where to hook it up. I have five wires at my thermostat, two going back to my ...
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859 views

Weathertron Xl1200 to Nest Thermostat

We have a Trane Weathertron Xl1200 heating pump with the thermostat pictured below and are trying to replace it with our new Nest thermostat. Our old system has a variable speed air handler and we ...
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475 views

What terminal to use on AC for C wire / nest dual transformer install

So i purchased a nest gen 3 and proceeded to install it. This is on a dual transformer system, separate boiler and AC system. The good news was i had a unused G wire on the Heat side that I was going ...
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252 views

Connecting Common Wire from thermostat to Air Handler

My apartment has a central heating/cooling HVAC system consisting of a gas-fired hot water heater which feeds hot water to a First Co air handler for heating, and a rooftop compressor which feeds ...
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Nest thermostat E74 error - no power to Rh Wire

It was working with no issues for last 3 years. Today it suddenly showing this error. Any help appreciated.
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4k views

Central Heat Won't Turn On When I Raise the Temperature on Nest Thermostat

I'm sure my heater is working. It's 47 degrees outside, and I'm only a little cool inside. My Nest thermostat is set to 67 degrees. The screen on my app (which agrees with the thermostat) is shown ...
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48 views

Nest E without common wire stuck in purge loop as soon as the Rheem heat furnace ignites

I have a honeywell hz432 and just installed a few NEST thermostats with a common wire and they seem to run fine. I added another NEST E thermostat, but this one didn't have a common wire, and when it ...
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337 views

How Do I Wire My Nest Hello Doorbell With A Plug In Transformer?

I wired up a nest hello doorbell to my existing chime. It rings fine but lacks enough power to operate properly. That’s ok, it was a little expected. Unfortunately, changing the old transformer is ...
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84 views

Intelligently Controlling 5 PTAC Units

I recently purchased a new apartment which comes with GE zoneline PTAC units that control both heating and air conditioning electrically. There are a total of 5 in my apartment, 1 for each bedroom and ...
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Adding C-Wire for Nest to Triple Aquastat Relay L8148J

Need some extra eyes and advice on how to add a common wire to our current boiler setup. We have a Triple Aquastat L8148E that has 2 wire that connect to our thermostat. Like many before me, I'm ...
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563 views

Nest 3rd Gen 24VAC two transformer issue

Hopefully this will finally solve the issue with my Nest. I bought a Nest 3rd Gen Learning Thermostat and followed the instructions to the tee. I have a two transformer system (Forced Air A/C and ...
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1k views

Nest thermostat installation to furnace and heat pump

We have T874G1196 thermostat by york (can only find honeywell documentation) MB7BM-1200K-B air handler H8HK015H-21 electric heater Thermopump (heating and cooling) We want to connect it to a nest ...
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84 views

How do I add a Venstar Add-A-Wire to my Lenox G12D2-82 furnace?

So I have a Nest Gen 3 thermostat and I am in need of a C wire. I have a Lenox G12D2-82 furnace. I have 4 wire set up. The Venstar makes 4 into 5 wires. I have a fan heat cool and power wires. There ...
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292 views

Can I just extend this blue wire in furnace for Nest thermostat?

First time doing this, don't want to burn house down. The brown bundle is coming from thermostat, the white bundle I suspect is coming from A/C unit. Do I follow these steps? Find a scrap piece of 18 ...
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How to identify a c wire?

I have 3 wires coming out from the wall at my new house (red, white, blue). It is a water boiler heat only system. The tstat was already removed unfortunately. I thought the blue wire was the C wire, ...
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Thermostat has two wires going into C terminal

Trying to help my dad install his new Nest thermostat - for some reason his thermostat has two wires going into the C terminal. I've searched and cannot find any other question about a setup like ...
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Can a Nest work in my setup (or am I stuck with Lyric, as they claim)?

Before crucifying me for the subjective question let me clarify that my question is quite specific if you read on. I bought an old home with bad insulation and a 55-year-old furnace 3 months ago. I ...
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123 views

nest 2nd gen, no common wire/terminal in the fan coil unit

I'm trying to install an older nest in my condo but it immediately complains that there's no common wire attached (error e24). I opened up the fan coil in my condo and there is no specific terminal ...
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I have 2 wire going into R, how should i connect to nest?

I'm installing a Nest thermostat: How do i connect the blue and red wire? Nest tech said i have two transformer.. do i split them into RH, and Rc?
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What powers a Nest thermostat? [duplicate]

I have an older thermostat I'd like to replace with the more modern Nest thermostat. The online Nest compatibility checker tells me that I have a compatible device. However, I'm not sure how it could ...
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50 views

How can I use home automation with hot water heating radiators?

My apartment (in a condo building) is currently using stationary PTACs (using electricity and hot water), which I'm planning to replace with a split-level A/C system (for cooling) and hot water ...
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55 views

Honeywell Thermostat to Nest E Dehumidification

I am trying to replace my Honeywell Prestige IAQ thermostats. I noticed that my downstairs thermostat has a dehumidification option (upstairs shows no such option). I checked the wiring at the ...
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1k views

Door bell partially rings randomly since Nest doorbell installation

(Somewhat related to this unanswered question: Doorbell constantly rings even after replacing switch but not an exact duplicate) My house had a modern wired doorbell (wired using Cat5e, if it matters)...
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48 views

Is this circuit correct for controlling old 750mv HVAC with NEST

I am just starting out with wiring and some other home improvements. Decided to install a Nest 3rd generation thermostat. I had a TH5110D Honeywell thermostat, so I pulled it out and found 5 wires ...
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205 views

Installing Nest on Viconics P117 Board

I couldn't find any help on forums or websites if anyone may have tried to install Nest by replacing old Viconics P117 Board and E117 thermostat. I have an Electric Furnace and Heat Pump configuration....
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Upgrading from a two wire analog tstat to a Nest, need help

I am looking to upgrade from an old analog tstat to a Nest. My old stat had only two wires connected (R and W) but the wire bundle had three. So I tried connecting the green wire to C and then turned ...
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Need to identify a common wire on my old HVAC

For Nest Thermostat 3, I am trying to identify a common wire on my old HVAC. The diagram can be found on the link below:

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