Ct100 Thermostat with C Wiring

Devices & Integrations
1

Ok, so I have a Ct100 Thermostat hooked up to control my Family room fireplace. Currently it is running entirely on batteries as there are only 2 wires coming from the fireplace to the thermostat. Replacing the wires is not a practical option. However…

On the otherside of the thermostat wall is my main house furnace. To run a wire from it to the thermostat would be a piece of cake. However…

The C terminal on the main furnace is already connected to the C terminal on my Nest Thermostat upstairs. So…

My question is: Can I run a second wire from the C terminal (which is already connected to the Nest) on the furnace to the C terminal on the CT100. In otherwords, can the C terminal on the furnace provide enough power for both the Nest and the CT100?

If the above is not a good option, can someone explain how they managed to connected a 24 volltg adapter to thiis thermostat??

2

No. It might work, but it’d be a Bad Idea. The “C” terminal should attach to a ground that’s part of the same circuit as the +24v going into the thermostat.

3

Thanks for the info. That makes sense.
So I found a Youtube video that explains how to hook up a 24v adapter. Unfortunately it is somewhat vague on the spec of such adapter. Seems to suggest any 24 ac/dc adapter will do. Am I to assume that This adapter will work??

4

To be honest, I have no clue what adapter might or might not work.

5

I dont have a c wire from my heater to my thermostat. I do however have power behind the thermostat in the form of electrical lines, same has what you plug your light switch into. Anyone know of a small transformer I could use that will fit in the box and can be hardwired?

6

something like this?? There are smaller versions of this I just dont recall their name.

7

Here’s a product specifically for that purpose.

8

I just went to home depot and found an LED 120 to 24v transformer. Its pretty small. Ill try it out.

Ill take pics after install.

9

I bought one of these. No issues at all. I plugged it in an outlet in my attic, which is directly above my thermostat. Snaked the wire down behind the wall and plugged it in the thermostat.

10

I dont have an outlet near by where my thermostat is. I do have electrical wire in a junction box right behind the thermostat so i need a transformer that can be hardwired.

11

In that case, I’ve used one of these as well when helping a family member in a similar situation. A little pricier, but it works.

12

I actually saw that one in home depot but it was pretty big and would not fit in the junction box.

I picked up this one.

13

I’m pretty sure it needs to be a 24v transformer, not 12v like the one you linked.

14

Just mount the honeywell on the outside of the box, it doesn’t have to be inside.

15

The manual shows 12-24v compatible for the Thermostat c-wire. My thermostat is in the central hallway and that thing would not look pleasing to the eye in plain site lol.

16

Haha, I meant mount it on the other side of the wall where your furnace is and run the wire through the wall.

17

Oh ok. I get you. Im hoping not having to do that and just use the electric right behind the thermostat for power.

18

Just a question on this. If I want to install an external adapter is this only working with the CT100 or can I use each thermostat to go that route if I don’t have the C wire?

Thanks!