Condensation problem in duct work

[Redfinn]

Good Lord I hate to do this to you guys, especially because I just registered to the site. I have had a condensation problem in my duct work since I built my house. I have in floor heat that is run off a dual fuel system, electric and propane. That system is controlled by regular 1 heat/1 cool standard round honeywell stats that report back to a Taco unit to control the boilers and pumps. I also have a Lifebreath clean air furnace, to handle air conditioning and air exchanging, not to mention I can heat the house with it too in the spring and fall as a "chill chaser". I am currently controlling that unit with a Honeywell VisionPro 8000 stat.

My house has two sections that have nine foot ceilings and the kitchen/livingroom has 12 foot ceilings. Where the condensation problem is, is located in all of the duct work in the north end of the house which has 9 foot ceilings. Just for grins I blocked those ducts off during the winter last year and th eproblem went back to the south end of the house, which also has 9 foot ceilings. There has never been a problem between the north end and south end of the house, which the central part of the house has the 12 foot ceilings. I better add that all the duct work runs through the attic in "unconditioned space". I should also add...on a seperate occasion I closed off the supply and return on the furnace and used it to circulate the air inside the house without getting fresh air from outside. This absolutely stopped the condensation problem.

Okay, now I have put powered dapmers (ARD's) in the duct work on the north end of the house and I am also adding two powered dampers to the supply and retun on the clean air furnace.

My question is....is there a stat out there that will allow me to control the dampers to the supply and return side of the clean air furnace, seperate from the dampers in the north end of the house? I will have the dampers in the north end of the house open when the fan on the clean ari furnace comes on, of course.

Does any of this make sense or has anyone else seen this problem? I know it is a bit complex for a simple Finalnder to explain in text without actually showing someone what I am talking about....Thanks in advance for anyone willing to try and answer this, but I am getting desperate....

[t527ed]

there would be ways to wire motorized dampers to open when equipment comes on to run.

other option is a thermostat that will run the fan for a short period every day to stop the condensation problem.