Right. That's why they dropped it down.
I can't do much about ducts that are embedded in concrete. They are what they are.
Originally posted by trane
Higher blower speed will not help if the ducts are to small. You need to measure the return duct and length, 16x8 will not handle the needed cfm for return. I don't think you need freeze stats or low amb. controls, you have a airflow problem.