A couple of observations:

1. Just because the wire at one end is green doesn't necessarily mean the green wire at the other end is the same wire. I'd check continuity of all the wires.
2. The black wire connected to Y1 is for a heat pump/AC - your thermostat can control a heatpump. Make sure all the settings are for a non-heatpump (gas) installation.
3. The York D3NZ024N05606A is a gas package heat/cool unit. So it looks like you have two gas furnaces(?) That's a setup for problems.

I'd definitely have the company that installed the rooftop unit come back, tell them of your issues and ask them to explain how everything is working while they fix the problem.

Thank you for the responses.

Yes two gas furnaces, the one outside with the ac unit does not get used. We didnt pick this unit, this is what they installed with no explanation why.

I was trying to avoid having to call the company that has done all of the work due to having a fair amount of home damage done last time.

I do not know how to check continuity.

I was half tempted to put the wires back where they were originally(I have a photo of it)(would it hurt to try?) but not going to risk damaging something.

I suppose my only option is to find a new heating company to check it all out, sounds like.

If it was hooked up incorrectly would that cause the temperature to be so much off though?

Take a look at those wires on the furnace in the picture. They should be solid, not stranded. I'm guessing the Y and Rc (which are stranded) go to the outside unit. And can I assume the outside unit does NOT have its gas hooked up?

> They should be solid, not stranded.

Why do you say that? Because it might indicate a DIY or clueless installation?

As long as the wire size (gauge) is adequate for the use, stranded vs solid wire makes no difference whatsoever. Both will conduct electricity exactly the same here.

When I moved my thermostat a few years ago, I had a big box of CAT 5 Ethernet cable, so that's what I used. Works fine. Wire is wire.

The big reason to use solid vs stranded wire is that solid wire is easier to thread into those terminals. With stranded wire, there can be a problem if a loose strand manages to contact an ajacent terminal. More likely because the terminals in a thermostat are so close together.

Just had a problem with our thermostat. It started running 2 degrees past set temperature. (I have it set for a 2 degree temp differential because the heater was constantly kicking on, running for just a bit and then kicking off...which was driving me nutz.)

After a bit of sleuthing, I found that the caulking backer rod that I had shoved under an exterior door (across the room from the thermostat) had become unwedged and there was a significant draft from underneath the door. (The backer rod was supposed to be a temporary fix that I did a couple of winters ago but forgot all about it...) Once I got that hole plugged up (with a better temporary fix), the thermostat quit heating past set temp.

I don't know for sure if the draft was the reason the thermostat got weird or if it was a coincidence.... Whatever, I did buy a new thermostat to replace the old one but haven't installed it since the problem seems to be resolved. Just tossing my recent experience out there as a potential cause because a new therm hasn't fixed your problem.

(Yes, I know my thermostat is in a poor location and should be moved away from drafts from opening/ closing exterior doors. Just no good or easy place to relocate it to and it's a low priority problem.)

"With stranded wire, there can be a problem if a loose strand manages to contact an adjacent terminal."

To reduce the chance of this happening, twist the small wires together counterclockwise (viewed from the wire end) after you strip the wire. That way, tightening them under the terminal screw will twist them tighter rather than untwisting them.

Can you post the photo how the wires were originally connected? This may give a clue as to what is going on.

Thanks for the tip. I will redo the wires.

I'll post a photo of the old one when I am by a pc.

" Why do you say that? Because it might indicate a DIY or clueless installation? "

No, because one set of wires goes to the furnace and the other set goes to the AC. Just wanted to confirm and all the wires going to the furnace were the solid set and hadn't been switched at the thermostat.

Still looking for the old picture. The one I thought was it was after they were done, still digging.

-unsure if I mentioned, after he switched or unhooked whatever wiring he said(could have been at themorstate or else where, unsure), when the A/C was run the fan in the furnace no longer would run(I thought it was suppose to), but again he said two were running. This heat issue has only started this winter since that was all messed with.

-I did clean up the installed wires(frayed) and also installed new Duracells.

-pretty sure after 3 new thermostats, the problem isn't the thermostat itself (as in set wrong or defective).

Is there anything at the outdoor unit I should check. The indoor furnace is right behind the wall the themosate is on, if I had to run new wire it is easy where I can handle it.

Again, I truly appreciate the help.

Get the guy back that swapped the wires.

"I figured it was going bad. I replaced it with the same one that was
installed and was sure to put the wires in the same spot the furnace guy
did(I took pics just for a reference also to really make sure). Now the
new stat did the same thing. So, I got another thermostat, we are on
number 3 now. Same issue."

What did Einstein say about the definition of insanity?