After several estimates, no Manual J or D calculations, and estimators who did not want to deal with the complications of my install, tight space and old ducts, I decided I would have to design my own spec system, and then put it back out for bid. So I purchased HVAC-Calc, and Im now going through all the Rheem Design Specs (yes, Im an Engineer).
Ive selected the Rheem RGFD-O9EZCM Upflow Modulating Furnace and the RARL-048JEZ AC Condenser (thanks for all the recommendations here). Now the challenges are figuring out how to shoehorn the new FAU and Coil to my 61 opening (with 19 Return Platform, original built-in with 2x4 and drywall.) I may tear it out to get the entire 80 opening.
I sure would appreciate any of you pros with Rheem / Rudd experience chiming in with your opinions.
1) With the 34 Rheem RGFD Furnace, I must now select the best Coil, the problem arises in the selection and associated transition to the existing 19 x 22 built-in Plenum. I will only have 1 12 available for the transition, depending on the Coil and Air Filter selected. I would prefer to go with the RCQD Coil (28" tall, 15.10 SEER), but would have only 1 to transition from the 19x22 Plenum to the 22x24.5 Coil, is this enough or will I have airflow, turbulence or noise problems? (the plenum is another 16 deep up into the ceiling cavity where it branches to three supplies).
2) If the RCQD Coil will not work, I would have to go with the RCHL Coil (17 1/2" tall, 14.75 SEER) and then I may be able to get 12 to transition from the 19x22 Plenum to the 22x24.5 Coil. Again, will I have airflow, turbulence or noise problems? (Could I get away with say 4" or 8" for the transition?)
3) Any other concerns using the RCQD Multiflex W Style Coils vs the taller RCQD Coils?
4) I will go with the Aprilaire 2200/2400 or the Honeywell F200E Air Filter. If I leave 6 between it and the cement floor of the return box, drawing air from all four sides, will this be enough airflow space to avoid noise or Static Pressure issues? (I need to keep it this shallow to have enough room for the Coil).
Thanks for the help and advice, SCR