Four Winds Air Conditioner problem

[cabinfourus]

First I'd like to introduce myself to you all.
My name is John Johnson and my wife and I live in a log cabin located in the mountains of NC. I am 46 years short of being 100 years old. I am a retired Marine and Nascar engine/team technician.

My wife and I are getting ready for a cross-country trip in our 2002 Thor Four Winds (28). We found this motor home about 2 years ago and started remodeling/upgrading it. It has 38,976 miles on the chassis and engine. We completely gutted the inside and changed the floor plan to meet our needs. So far, I have installed a new roof, including wood, a second rear ac system, two new windows, resealed all the cargo doors, rebuilt the plumbing, and am currently remodeling the bathroom and shower. It has been a wonderful project! We have enjoyed this rebuild.

Our trip doesn't start until we get our son off to college. We have a year to get this thing ready to go. We have used our motor home a couple of times and enjoy it. I have come to a problem that requires more knowledge than my simple mind can store.

After sitting, covered, and stored properly, for around 5 months, we pulled it out to get back to work. I went to turn on the original Mach 3 AC system and it wouldn't turn on. The heater blower started blowing but nothing related to the AC would work. I researched the problem using my diploma from the university of a Google search bar and decided to replace the thermostat. After replacing the thermostat, the AC will try to come on but quickly turn off and the heater blower will turn on. I have checked all of the wirings with my volt/ohms meter and didn't find any issue with the wiring. I am using a thermostat for standard home AC systems but it is battery-powered, so the voltage difference is not an issue. I am hoping someone may have had an issue close to this and can help me out.

Thanks for taking time to read my post and I pray you have a
wonderful day.

John

[triplewide]

Are you confident the thermostat is wired correctly?


For the furnace blower to come on, 12 volts must be being applied to it I would think. With the thermostat in AC (air conditioning) mode, the thermostat should not be placing 12 volts on the furnace wire. Is it possible a screw or nail penetrated the thermostat wire?



Did it work when it went into storage? Was any work done on the coach after it last ran properly?

[Sweetbriar]

I replaced the Coleman thermostat several years ago with a residential and if your Four Winds is like my Four Winds and the thermostat wiring followed the standard color coding you could try to force the A/C on with jumpers to bypassing the thermostat and verify the A/C is responding correctly to calls for blower and cooling.

What you should see at the thermostat is -
Red wire to the R terminal which will be 12VDC from the furnace via the A/C.
Yellow wire to the Y terminal which will turn on the A/C compressor
White wire to the W terminal which will turn on the furnace
Green wire to the G terminal which will turn on the A/C blower

There might be a fifth wire which is used to set the blower speed to low. I can't recall the color but a residential thermostat normally does not have the blower high/low speed function.

Jumper R to any of the terminals will turn on the associated function. If not you will need to trace the lines to see how your system is set up. Normally when the thermostat calls for cooling it will set for both Y and G with 12VDC to turn on the function. If the wiring is correct and everything works as expected by jumping then maybe the thermostat isn't happy with something.

Also if you have a thermostat that will automatically switch between heating and cooling (what I have) ensure you have if programmed so the two functions do not over lap and are separated by a couple of degrees. In other words if your minimum temp for A/C is set to 70 then set the maximum temp for heat no higher than 68 or so. A few degrees of separation is needed as the switching action of the thermostat isn't exact.

I am 39 years short of being 100 years old, a retired sailor but prefer two wheel racing with a both left and right turns on the race course.