No C-Wire for new wifi thermostat.

[edcantu9]

Hello all. I received a new thermostat with wifi capability to be able to control it with laptop and phones.

It states it needs a C-for power. My wiring only has 4 wires R,W,Y,G. The new one also needs a C.

I looked for an extra unused wire but there is none.

Here is a picture of the furnace wiring. It looks to have a C wire but it is coupled with another wire and it ends at the pictures of the capped wires.

Anyone have any starting advice on how to get this done?

 

[brewchief]

You will need to pull a new wire, where does the wire run now and is there access to most of it?
If it's an unfinished basement or an attic you should be able to trace the route and find where it goes into the wall. With a little bit of luck there won't be staples holding it in the wall.

Sent from my XT1254 using Tapatalk

 

[dreasoner]

Like brewchief said,pull a new wire. If the old wire is not stapled, use it to pull in the new wire. Can also try a long flexible drill bit with a hole on the bit to drill a hole thru the upper of lower wall plate. The bit I use is about 5 feet long and flexible. Can feed it thru the hole in the drywall behind the old stat. I have also used fishing line with lead sinkers to fish wires thru walls. In a pinch, you can remove baseboard trim to cut holes in the wall to aid in getting wires thru bottom wall plate. Hope these ideas help. Just be creative when faced with fishing wires.

 

[edcantu9]

In the picture where there are caps, they joined the new wiring from the furnace that was recently installed to the old wiring from the old furnace.


In that picture is the 4 conductor bundle from the old furnace headed to the thermostat.

A bundle headed to the AC outside. This is where the C and Y wire from the furnace are going to. They are going to the wire going outside to the AC. (A white and red wire connected to another white and red wire.)

I am thinking not to over complicate things, buy some 18g wire. A single strand and run from thermostat to this cap where the C wire is capped on and include it in there.

And then I would have a C wire at the thermostat and leave the other wires alone. Anyone see any problem with this?

 

[Brian_WK]

It would "work" but you would be removing a layer of insulation from the wire by taking it out of the jacket. And if you are pulling one wire might as well pull more and have room for future upgrades or if you were to have a wire break in the wall. I would use the existing wire to pull a new 8 wire and call it a day.

Brian

 

[edcantu9]

Hello all, in hopes that in might help someone in the future.

I ended up buying 18-2 wire and left the insulation on. I did not mess with the other wiring.

Fished it through, added one on on the thermostat and other end on the C port in furnace.

It is up and running now and is able to be controlled through laptop, phone, and tablet!