You guys have been great answering everyone's questions (along with a few of mine). I have a duct type question I would like to get some opionions on. I am in a condo, unit above me, below me, and behind me. I face west, lots of windows in Vermont. The units on West side of buiding have 2 tons of cooling (1200 sqft). Pretty sure it is oversized from what I read on here. For example when it does reach 90 here, unit never runs more than 15 minutes. Also, I really feel the air a lot. I can never seem to get a good setting on the tstat. Sometimes feels to hot or too cold. I got a good vision pro 8000 and that helped a lot but still, I can surely feel and hear it when it's on.
Anyway, I have one metal duct that runs through the center of the apartment. It is roughly 28" by 7 " in an enclosed soffit (8 foot ceiling in the apartment). The duct is roughly 20 feet long and all registers come off that one main duct. I have 6 registers.
2 7" by 6"
2 9" by 6"
1 6" by 18"
1 13" by 18"
All are rough measurements of the outside of the grill. In all cases the actual opening is slightly smaller. My fan coil is mounted in a small closet not ducted return. The fan coil on a pedestal and there is simply a return grill in the side of the closet. The return grill is 17" by 9". Also, the door to the closet has a 1 inch opening around the entire parameter so it also functions as a return. Roughly another 150 sq inches by my calcs. So after reading on here looks like my return is undersized. Problem is if I open the door to the closet, essentially making my return size 1026 sq inches.. HUGE. I didn't see any difference in the supply air from the registers. So that led me to believe I am starved on the supply side. So I decided to take the grills off and I found a removable back piece that allows you to shut the vent. I took all of these off. See pic.
I then had tons of air so I thought I did a good thing. I then saw a difference when opening and closing the HVAC closet door. Problem now is I was getting too much air!! You can now see the leaves on the plants on the other side of the room blow quite a lot. Also, I got lots of duct noise. Like the duct metal was flexing. Also, as you guys realize, my humidity level increased a little bit. It was around 55% when it was in the 60's outside and raining.
So I then went into the air handler and set the CFM adjust to low. As I am sure you know, that allows the air to be reduced by roughly 10% from nominal. I still had a lot of air coming out of the vents, but it was a little better. Still had duct noises.
So, now I have put the metal pieces back on the grills. I call them restricters. My own termonology since they do seem to restrict the air. The fan coil is still on low setting. Now the AC is much quieter, no more duct noises and I feel the coolness without feeling the breeze if you know what I mean. It feels as it should. I have lived in houses that have central air and I know shouldn't feel the AC so much as I did. It nows feels better than it ever has. The temp seems more consistent too.
I know you guys are going to tell me they should have done a calc and the ducts should be done correctly. This condo is 2 years old so none of that is going to happen. The ducts are buried in sheet rock soffits so they aren't changing.
My question is IF, and I do mean IF, I never get a freeze up of the coil, am I ok with the way things are? I will check the coil for the next few days and see if I get low air flow. If there is ice, I will go back to nominal and leaves things alone. If I don't get ice, then is there a problem running partially starved of air? I am thinking maybe early motor failure? I think just the motor can be changed so if that goes out in 5-6 years I think it's worth it for the quiet and confort.
Any thoughts? Am I crazy?
Here are some pics to help you guys.