Questions tagged [thermostat-c-wire]
The "C" or Common wire provides a way to get constant 24VAC power to the thermostat, now required by many newer thermostats with WiFi and/or touchscreens.
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How to add a C wire to a lennox G8-137 wd-64280-L5
I have a Lennox G8-137 WD-64280-L5 furnace. I am trying to update the wiring going to the thermostat due to it being cloth covered, and I also plan to put in a google nest thermostat. Where is my C ...
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How does a Google Nest power connector work?
I am looking at the installation instructions and they all show that the power connector goes back to the furnace/AC control panelIf this is installed just to make sure the thermostat gets enough ...
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Adding smart thermostat (nest) to burnham series 2 boiler
I’m trying to add a nest thermostat to my burnham series 2 boiler with two zones. My original thermostat has a red and white wire going to W and R with a jumper from R to RC. See first photo.
Where ...
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Nest thermostat and no C wire at my boiler
so I bought a nest thermostat and it keeps running through the AAA batteries, recommending that I use a C wire, though there's just 2 coming out of the wall (red and white). I got C wire/power adapter ...
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No C terminal, where to tie in smart thermostat
Trying to figure out how to connect the Ecobee adapter. I can follow up with more pics and info / questions (like connecting via the transformer), but everything I’ve read up on has led me to this ...
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C-Wire for L8148J Thermostat
Thanks for very informative videos. Where do I connect C wire on the 8148J Aquastat to get 24 v for the Nest thermostat? Thanks
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Installing c-wire adapter on hvac
I'm installing an Amazon smart thermostat.
The hvac control board has 3 of the wires that the instructions state to disconnect and connect to the adapter (G, W, Y). But it's missing R, and Y has two ...
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Where to connect a common wire to a Burnham alpine Furnace
Like many on this site I am trying to install a smart thermostat. I have 3 wires, 24V Red, white, and blue at the thermostat, but only 2 down at the boiler. My boiler is a Burnham Alpine model number ...
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Where does my C Wire go?
Changing thermostat and need to connect c wire at furnace. I connected to the brown bundle based on the wiring diagram and it worked to get power to the new thermostat. However, only the the fan runs ...
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Ecobee no C-wire, no panel in air handler
Looking to install an Ecobee but have reached a C wire issue. The Ecobee support didn't think it would be possible without adding another wire but they didn't have the schematic. Just wondering if ...
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Y wire question: Help to connect smart thermostat with C wire adaptor
Trying to install an amazon smart thermostat with a c wire adaptor.
On the thermostat end, pretty straight forward. Rh, W, Y, G wires. Noted that a blue colored wire is Y wire. SEE PICTURE
When I went ...
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How to connect my C wire (blue) to the transformer? HVAC
Trying to connect my smart thermostat up, but the C wire (blue wire) is not connected to anything, it’s just there capped off . (Bottom left)
Anyone know where I should connect the blue wire to so it ...
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How can I get power to my new Ecobee thermostat?
I purchased a new Ecobee smart thermostat which requires a C wire (the Nest unit did not) to power the thermostat. I located the blue C wire behind the thermostat, but it was not connected on the ...
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Do I have a wire to repurpose as a C-wire?
Do I have a wire to repurpose as a C-wire??
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Where to add C-Wire connection for thermostat
I’d like to ask a follow up question on this thread below.
How can I add a "C" common wire to this system?
This was the fix: In the wiring diagram in the PDF you linked, the BR (brown) wire ...
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Do I have a C wire (or something I can repurpose)?
Pretty old looking thermostat, but the house itself isn't that old (I think 1997).
There's no terminal with a "C" at all here, but there's 6 wires including a "blue one" which this ...
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Finding the 24V C-wire from Carrier AC blower to connect to a Smart Thermostat
I want to install a Smart Thermostat to control my AC unit. The current "dumb" thermostat is battery powered and does not use a C-wire (see current thermostat wiring pic). When I look at the ...
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How to make c-wire to a new boiler using Fast-Stat common maker?
I'm seeking assistance regarding connecting a C-wire (for Ecobee) to a new boiler using the Fast-Stat common maker. The new boiler currently has two thermostat wires available for connection. However, ...
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Old furnace no C terminal
I’m trying to install a smart thermostat and my furnace does not have a C terminal. The thermostat has an unused blue wire, and I connected it to what I thought was a common, but the unit is not ...
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Y wire on thermostat connected to C on furnace
I have a very similar problem to the question Why is Thermostat Y wire connected to C terminal on furnace? . The big difference is that I dont have an "extra wire" to use. Only 4 wires go to ...
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Old house, want to update thermostat
I bought an older house (1897!) and am slowly but surely going around and repairing things and updating them. I want to update my thermostat to an ecobee one. We only have radiators and no AC, but ...
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Adding a C wire to an Intertherm system
I am trying to add an Ecobee smart thermostat to an older Intertherm furnace and A/C. I have extra wires running to my thermostat, but can't figure out what to connect to in the furnace wiring. Any ...
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Can’t find C Terminal Burnham Series ES2
Try to install Nest thermostat 3rd gen. I have 3 wires coming from the furnace: R, W, and G. I connected them to Nest pretty simple there, but low battery, Wi-Fi not working on a daily basis. There is ...
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Where's the c-wire on my air conditioner?
I'm trying to install a smart thermostat in my home. It has only an external air conditioner (model P3RD-042K, here's the manual/wiring diagrams), no heat. The current thermostat has an unused blue ...
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Trying to figure out which is the C wire to use for my new Honeywell Wifi Thermostat?
I am trying to figure out which one of these 3 blue wires is the correct one to use as my C-wire.
I have a reg Honeywell thermostat but recently bought a WiFi Honeywell thermostat. When I pull ...
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Separate thermostat power source from HVAC unit for home battery backup
Here's my situation. I have two HVAC units connected to Ecobee smart thermostats. Both have C wires and were standard installs.
We are having solar panels and an Enphase backup battery system ...
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Is there a solid-state version of this relay/transformer combo?
One-line summary: Is there a solid-state version of the White Rodgers 90-113 Fan Control Center (Transformer and Relay Combination)?
EDIT to answer question: The thermostat draws 0.146A (3.5VA / 24V).
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Replacing heat only thermostat
I have a two wire standard thermostat, RH & W
It is heat only for my downstairs area and has a zone valve.
To my boiler the RH wire goes up to the zone valve and the W wire is going to R location ...
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24v Doorbell Transformer for Smart Thermostat
I have searched for this topic and the previous answers are not conclusive to me so I will try again with my specific situation. Thank you in advance for your help!
Current situation: I have a 16V ...
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How do I go about wiring 3 Nests to a boiler with no C wire
I’ve seen a version of this question in a few places but nothing really fits.
I have a boiler and hot water baseboards. It’s a three zone system and I installed 3 Nests but there is not C wire and no ...
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Thermostat common wire identification for Nest thermostat
There are 5 wires at the old thermostat. No C wire. Dual system. At HVAC unit there is no mother board, only wire caps. The colors don’t match between thermostat and outside unit. I'm trying to ...
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I'm trying to connect a thermostat C-wire... no voltage between W/R and COM on control board?
I am trying to add a C-wire for a smart thermostat on an existing gas furnace heater (no cooling). The control board is a HK42FZ065 and the condensate pump a cb151ul.
I tried measuring the voltage ...
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Ecobee Thermostat / Common Maker / Gas Valve
I have a two-wire thermostat and an old forced air gas furnace in my house. When you open up the cabinet, inside you find a Dayton 2E228 Gas Valve and it is wired to an external 24VAC Transformer ...
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Ecobee SmartThermostat - Blue connected to W at furnace, what to do?
Trying to install my new ecobee SmartThermostat. Furnace is a Trane heat pump, 20 years old from when the house was built.
When I looked at the existing thermostat, it has RGWY.
So I thought I needed ...
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Just moved in and want to hook up Nest/Google thermostats but need C wire
I’m trying to figure out which wire(s) are my Common so that I can set up my Google thermostats. I don’t have one used right now, just 2 wires for my four thermostats. I need to connect the 2wire to ...
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What is correct Nest setting when adding my own C-wire? (i.e. without using Nest Power Adapter)
I am adding a Nest (not Nest Thermostat E or Nest Learning Thermostat) to a 2-wire boiler system. Fortunately, the existing thermostat wire has free conductors. So I connected a 3rd wire from the C ...
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How to add Thermostat C Wire to Furnace TH/TR and Transformer
I am trying to figure out the proper wiring for a C wire for my thermostat.
My 24v transformer and the current thermostat wiring at the furnace are shown in the pictures below.
Can I wire a thermostat ...
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Replacing my thermostat: Do I have enough wires?
I have an old thermostat that powers my kerosene furnace in my mobile home. It also is powered by battery I believe. I noticed when taking the cover off there is only 4 wires and the previous owner ...
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Can I use a Doorbell 24v transformer as a C-Wire transformer?
Can I use my currently working 1970s doorbell 24v transformer as a C-Wire transformer? I'm installing a Honeywell Home Wi-Fi 7-Day Programmable Thermostat (RTH6580WF), Requires C Wire.
I ordered a ...
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Where do I connect my unused C wire to my Goodman Heat Pump?
I understand similar questions have been asked but I have been unable to extrapolate what has worked for others to my own system. I am trying to upgrade my thermostat to the Ecobee Lite. I have an ...
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Can I use a Honeywell Cwire adapter on a 2-Stage Condensing Furnace?
I'm currently trying to add a Amazon smart thermostat to my Trane UH2B060A9V3VA furnace. When I had my AC service earlier in the year I mentioned the project to my heating and cooling guy and though I ...
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Tech says furnace has no ground [closed]
I hooked up an Ecobee 3 thermostat that has worked great the last couple years. This weekend my furnace went out.
I had a tech came out and he got it going again but told me it would work better with ...
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Trouble getting power to Honeywell T9 from furnace
My previous, antique thermostat was only a two wire and we are trying to upgrade to a smart thermostat. I'm having trouble getting power through the green "C" wire though and I'm hoping my ...
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Finding the C Wire for the LH33WP003A Control Board and Ecobee Premuim
I am installing a new Ecobee Smart Thermostat. My old thermostat didn't use the C-Wire. However, when I pulled the cable out of the wall their is a blue wire. I hooked it to the Ecobee but it didn't ...
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How to install C wire in this setup?
I know this question has generally been asked but every system is different and I’ve seen nothing like mine.
I have a tankless water boiler for baseboard heat with a separate electrical control panel ...
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another common terminal question on an old furnace control board
I've spent quite a bit of time trying to sort this by looking at existing solutions but still not following. Can you tell me where I can tap in to pull a "c" wire from to the thermostat?
I'm ...
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Connecting Ecobee to Mastertrol Mark V
UPDATE:
I was able to wire a C-Wire to the Ecobee. So now I got 24 Volt at the Ecobee. But it still won't run.No sign of action at all. Maybe because I got no green connection?
Any ideas?
We ...
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Smart Thermostat - C Wire
I'm about to go out and buy a smart thermostat for my place and had a question about the 'c' wire (common wire). From what I've read online, the blue wire is commonly known to be the c wire for the ...
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Connecting “C” (common) wire for Nest thermostats
I am planning to get two Nest Thermostats for my 2 zone HVAC system. It looks like blue C wire is already there for both thermostats, but not connected (existing thermostats run on batteries). I ...
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Adding a C wire to Nest learning thermostat 3rd gen
I'm trying to add a C wire to my Nest thermostat, I already had the C cable on both ends but it wasn't connected, I went to the attic and connected the blue wire from the thermostat wiring to the C ...
