Help Please !! A/C upgrade

[twainharteartis]

I am replacing my Coleman Mach A/C units with Atwood units. Both are controlled with wall mounted thermostats. The Coleman is analog the Atwood is digital. I have the 115v power hooked up and the thermostat is plug in. I have the 12v hooked up. There are two blue wires that go to the furnace they connect to the old plug in wires (each wire uses separate plug for each wire) that were used by the old thermostat. My problem is what color wires do I use? How do I find out what wires go to the furnace? Hope someone can help me. Need to get this working soon want to drive the RV to Portland for sons Graduation (PHD) only have to next week 08/08/17.

[twainharteartis]

blazenpm wrote:
What are your plans for the Coleman A/C units on your RV? Do they still work? I wanted to pvt. message you but you only allow people on your buddy list.

No the one one the rear the compressor took a dump. They are both 20 years old so I replaced both. I kept them cleaned out and at 20 plus years old they were coming to the end of there usefulness. One died and the other who knows how much life was left. So I replaced both while I was into it. They are running now. Can't find the wires going to the furnace. But will fix that when I get back from our trip to our sons graduation for his PHD.

[falconbrother]

Coleman AC units have always been good to me. I've never had a single problem with one of those.

[blazenpm]

What are your plans for the Coleman A/C units on your RV? Do they still work? I wanted to pvt. message you but you only allow people on your buddy list.

[hostage]

GordonThree wrote:
So you want the new air conditioning to control the existing furnace?

On the old thermostats the terminals where the blue furnace wires connected should have an embossed label one or two letters

These same letters should be present on the new thermostats.

Maybe someone with the same model can help, I'm out of ideas without more information.

no he wants the ""new thermostat"" to control the old existing furnace and the "NEW AC" system ;;; LOL

[GordonThree]

So you want the new air conditioning to control the existing furnace?

On the old thermostats the terminals where the blue furnace wires connected should have an embossed label one or two letters

These same letters should be present on the new thermostats.

Maybe someone with the same model can help, I'm out of ideas without more information.

[wa8yxm]

Uh, Just so you know.. I'd call coleman (Which sucks air in through the condenser so it's easy to clean) With Atwood (Which blows so the dirt and crud is inside and you got to take it way more apart to clean) a downgrade.

Or did you mean upgrading from 13.5 to 1500.. I did that, One Advent air, one coleman (Originals were Carrier's but of course can not do them any more.

Digital or analog if the thermostat has the same wires, it should work

Usually fan high, (Medium is an option) low and Compressor On/Off.

[twainharteartis]

GordonThree wrote:
How many wires do you have? Can you post a pic? Shouldn't need the furnace in August right?

There is the three 115v wires black /white /green. They are connected now. There are (from the A/C) one harness that plugs into the harness from the thermostat so that is connected. That leaves two blue wires and one red and one black.The red and black are the 12v wires to power the thermostat. the blue wires go to the furnace. The old thermostat has a 5 wire harness that went to the old A/C unit. two of those wires should go to the furnace. The colors are red, yellow,blue, green and white. The manual said the two blue wire can be hooked up ether way. IF anyone knows what wire I should hook to the blue wires coming from the new A/C unit PLEASE let me know or how I can figure it out.

[GordonThree]

How many wires do you have? Can you post a pic? Shouldn't need the furnace in August right?