Good morning I have a ICF foam block house, with 8 inches of closed cell insulation in the attic. The house is 900 square feet. The air exchanger ducts go from the basement into the attic to 2 inlet and to discharge ducts on the ceiling. They are 6 inches in DIA. I have a back draft damper in the system and verified no air is comming in from out side. But with the exchanger off I have a fair amount of cold air blowing into the house from 2 of the ducts(fresh air in duct) the duct in the attic is 6 inch flexible insulated duct and about half covered with the closed cell. I have no clue on why I have cold air coming in and I need help on what I can do to fix it. Thanks Larry

Sorry for posting in this area. I didn't realize it until after I posted it. And I don't know how to move it Larry

Thermal camera?

Thermal camera for what??