Coleman DGAA090BDTA question

[Robert]

Hi,

Ok, will be back with you shortly, think I've spotted something.

Would be easy to check or rule out if you could get a length of 4 wire t-stat cable long enough to run from t-stat to furnace.


Thanks,
Robert

[pigaman]

Hi Robert
I don't have any 4 conductor cable here at home, but I can get some on Monday when I go back to my test lab. Even a short length might work. I could wire up the t-stat remotely in the furnace room just rule out the original cable. BTW, I am an electrical test engineer by trade and actually find this kind of fun to work through. You guys are a big help

[Robert]

Here's what you should do. Turn power off, disconnect the white wire from t-stat and from Furnace.

Then disconnect red wire from t-stat and from furnace end wherever it is connected.


You then need a length of t-stat cable to run from furnace to t-stat.

Connect the red and white from the new cable to the t-stat and the other end of the red and white at furnace where they were previously connected.

Turn on power and set t-stat to COOL/AUTO and designated temp.

If all is ok and remains that way for a test period (few hours would be good), then you can turn OFF power and run that new wire in wall from furnace to t-stat.

Be sure to read all replies and answer all questions and do all tests also.


When you have t-stat to Cool and both heat and cool are running, if you switch t-stat from Cool to Off, do both heat and cool shut off ?

To get the heat off, do you always turn t-stat off only or do you have to turn breaker off ?


Thanks,
Robert

[pigaman]

Hi Robert
When both systems are running at the same time and I turn the t-stat to OFF, both systems shut down. I only have to turn the t-stat to off to shut down the burner, no breaker. Thanks again.

[pigaman]

Hi Robert
I found the problem and you were right all along. My t-stat cable has a short (3-4 ohms) from the green wire to the white wire. I made up a short jumper cable in the furnace room with my t-stat on one end and by-passed the original cable and all systems are go. My cable is run up and over the ceiling and must be stabled down or something because I can't pull it from ether end. The furnace is located in a utility room in the middle of my Marlett modular home. I could just relocate the t-stat to the wall on the other side of the furnace compartment. In any case, the mystery is solved thanks to you guys. I put my original control board back in and it works fine with the cable by-passed, but it doesn't hurt to have a spare anyway. I have recommended you guys to quite a few folks in my 55+ community. Again, thanks for your timely assistance.

[Robert]

Hi,

You're very welcome, glad you got it resolved. I hadn't had time to get back on here until now, but had read your other reply or had it read to me.

I got on now to tell you to check at furnace for a possible short between green and white,LOL.

I had ran your info through my head thinking of different scenarios and that is what jumped out as possible fault.

I knew it was in the cable between t-stat and furnace after you gave the test results, but then it didn't match what you said the results were.


This is where not being there takes some extra thoughts on it. So I kept running it through my head until it hit me like a brick.


Good job on your end testing. Thanks for recommending us also.


Take care and best wishes,
Robert