Linked Questions
15 questions linked to/from How do I identify the C terminal on my HVAC?
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1answer
17k views
How to connect thermostat C wire to Weil-McLain CGa boiler? [duplicate]
I have Weil-McLain gas boiler for hot water heat and going to install WiFi thermostat that requires common 24V 'C' wire. I do have a free wire in the cable but cannot figure out where should I connect ...
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2answers
8k views
Which terminal should I connect it to for a “C” wire when none are labeled “C”? [duplicate]
I am looking to replace my old battery operated thermostat with a new wifi model. There is no "C" common wire connected to my old thermostat. There is a blue wire that is at the thermostat but cut ...
2
votes
1answer
6k views
How can I add a “C” common wire to this system? [duplicate]
I would like to add a "C" / Common wire hookup to my hvac system and get a fancy new thermostat. I've read How can I add a "C" wire to my thermostat? and still have some questions.
First of ...
0
votes
1answer
3k views
How do I add a C/ Common wire to my “Specific” HVAC system? [duplicate]
I just bought a new WiFi thermostat that requires me to add a C-Wire at the furnace. I have read the questions related to my issue but would like a suggestion on my particular (incredibly OLD) furnace....
1
vote
1answer
2k views
How do I connect a C-wire on a Triangle Tube Prestige Solo 110? [duplicate]
I purchased a Honeywell RTH6580WF to use with my recently installed Triangle Tube Prestige Solo 110 propane boiler. I only have two wires at my existing heat-only thermostat. I understand that the c-...
1
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1answer
91 views
Installing a Honeywell Wifi thermostat and need a C wire connection [duplicate]
My current thermostat is wired as follows and the wires are from my Separate heater and separate AC air handler:
W - From my heat
R - From my heat
Rc - From my AC Handler
Y - From the compressor
G -...
100
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7answers
577k views
How can I add a “C” wire to my thermostat?
So, the spiffy new wi-fi thermostats want power on the C wire from thermostat, but the old thermostat doesn't have a C wire at it. What's the easiest way to add the C wire/24 volt to the thermostat ...
4
votes
2answers
36k views
Where do I connect my C wire from my thermostat when there are two transformers?
I have a Laars gas boiler that has 3 heating zones. I want to replace the old mercury honeywell tstat on the 1st floor (heat only) with a newer honeywell RTH9580 wifi model. I've taken pictures of my ...
1
vote
6answers
17k views
I am installing a Honeywell RTH6580WF with a TACO SR504
The current installation does not have a C wire. So I have run an extra wire and am now confused as to where to connect it. There is a 24VAC connection and a common connection. Comments say that ...
3
votes
3answers
8k views
Where's the C terminal on my boiler control?
The new thermostat I purchased doesn't run on batteries, and needs 24 volt power. I have only a red and a white wire connected between the boiler and the thermostat, but there is also a third, unused ...
0
votes
2answers
1k views
Where to attach the “C” wire to my furnace?
I am upgrading to a new thermostat which requires a "c" wire to power it. I have an unused blue wire running from my thermostat to my furnace that I plan to use as the common wire. However, I am ...
1
vote
1answer
674 views
Install Common Wire (unable to find terminal or 24 VAC)
I bought a Nest 3rd Generation Thermostat. Live in a 2 family home, where my floor/basement has the boiler room/furnace. I have a Laars Mini Therm Furnace Model JVT. There's a thermostat upstairs as ...
0
votes
1answer
288 views
Where to connect Blue C Wire at old furnace?
I have looked at other responses and each layout is a little different. Looking to connect a Smart Thermostat and need to know where to connect the Blue wire at the Furnace. See the attached picture....
0
votes
0answers
96 views
Help adding C wire to furnace - Heat only system
Looking to add C wire into my furnace. Heat is currently running on two wires with older thermostats. Luckily the in wall wiring has three wires.
Any help to point out the C wire for my setup? Or ...
2
votes
0answers
40 views
Replacing my Honeywell thermostat with a Nest heatlink in the UK
Can someone help with this.
Trying to pick the C wire and the NO wire from here.
Please note I am in the UK
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