The new HVAC tech came today and he seemed to be very knowledgeble. Maybe it was one of you pro's from this site that got tired of this long post and decided to come and solve the problem yourself. Beenthere?
Anyway he spent 1.5 hours going over my system (he indicated he had never met a customer that was as knowlegable in this area as I am. I told him I learned at the University of "HVAC-Talk.com" .
He pointed out additional errors from my install beyond those I have already posted on this site. For one, they did not bother to put a trap in and he reccomended something called an EZ-trap.
He also had issues with my ADP coil and told me I can expect leaks in a year or two with the high pressure 410a but it is still better than the trane coil...and Trane knows and he expects an improved version within the year.....but that's another story.
To the issue at hand. He said my issues are rather easy since they can all be addressed in the unfinished basement.
Basically I have two supply trunks delivering air (the 3rd is closed off as I have no intention of directily heating/cooling the garage area). Of the two, one is 8x9 rectangular and has five seperate round 5" runs that lead to 5 differrent locations throughout the house. The 2nd is 12x9 rectangular and has 11 seperate 5" round runs that lead to 11 different locations through out the house.
He said the 8x9 trunk is capable of moving 450 CFM but the 5" runs are only capable of moving 50 CFM each. Since I have 5 runs on that line it means only 250 CFM capacity is being utilized even though the trunk can move 450. He said the 5 inchers can easily be replaced with six inchers because they all connect to 6 inch oval duct right before leaving the basement area. (he said 6" oval ducts can handle the flow of up to 8" round pipe).
He said with 6" runs replacing the 5" runs, each one can move 75CFM so now 375 CFM can move through that trunk instead of 250 CFM.
Same story for the other trunk except I am already at CFM capacity. He said the 12x9 trunk can move 550 CFM and my 11 seperate 5 inch runs already total to 550 so increasings those runs to 6 inches provides no beneifit.
I beleive this is where Beentheres helper duct comes in and saves the day.
Since it can be attached to the plenum and pull another additional X CFMs to add to the 550 CFMs in trunk 2
The tech beleives if I have these changes made it should significantly reduce my static pressure.