I need to replace the transition pieces from my 3 1/2 ton 1400CFM Trane gas pack to the trunks inside my finished basement. The existing pieces are taped together and just resting against the gas pack openings with no flange to secure them. Just a little tape.
It looks like someone made the mess when they retrofitted the gas pack years ago. Possibly it was a split unit before the gas pack was installed.
The trunk is also pretty poorly constructed and leaky.
The opening for the supply on the gas pack is 9"x17".
My supply trunk is a metal 16"x20". Is there any reason for the trunk to be that large? I assume it was a plenum for a split unit at some point in the past. The return is slightly smaller.
The supply trunk comes in the house and it immediately turns 90 degrees and goes up 4' to an end cap. 3 round 6" flex ducts come out of the end cap and another smaller trunk (8"x14") feeds out the upper side of the trunk to rooms farther away.
The unit is for the 2 story part of my split level, about 1800SF.
The main ground level has another gas pack, I'll get to that one later.
I have some room to make length changes if needed.
To replace the 16x20 is a custom sheetmetal job.
Can I downsize my trunk to an off the shelf size?
8x24 is the largest I can find locally.
Having someone come in to design a Manual D system isn't in the bank account right now. I just want to get it working and sealed up correctly.
I hope this all makes sense, I was up pretty late last night mixing concrete
to fix the mess under the gas pack
Let me know what I have left out...