Problem: humidity levels reach above 70-75% in areas of the room...shooting for 60%....70-75 can cause mold.
Reason: the air handler is too big for the 270 sq ft./2430 cu. ft. room with R27...etc. Or at least that is the theory...
Using R410a I believe. I think the EPR is all the way out. The coil temp was brought down as close as they could to freezing...I think it was like 34, and there was some accounting for the very long lineset.
System: MagicAire DVA10 air handler with a Copland 1.25ton BTAH-A125. Line set is ~85 feet long with 8-9 90s...yes you read that right. Return ducting is short ~1', supply is ~30 feet of ducting, 4 runs...16" into 2 x 12" into 4 x 8"...All galvanized...all insulated with the bubble wrap stuff with spacers...We've spent a lot of time sealing the system from the adjacent utility room, where the air handler sits. Room has closed cell foam insulation...air tight doors, etc..very little if any air infiltration...the ducting was sealed several times..
Suggestion was to limit the airflow...As a test, I closed the dampers on the supply vents about 50% (they are 4 of 4x18s) and it does maintain humidity a little better...but it gets loud. Idea was to put the dampers in the 12" pipes and use those to limit the airflow. I am worried about adding pressure to the air handler, however..
Also, I think the duty cycle is pretty low...no where near the 80% they want.
Temp. is maintaining well, at 50 degrees. liquid variance is just .4 degrees...air variance is about 2 degrees or less. I set the control system to turn the unit on with a 2 degree limit - set at 49, it turns on at 51.
Note the humidity is some areas of the room is closer to 60-65...Oddly...the room varies quite a bit, with the area by the door is heavily impacted by the door opening...As you can imagine, it is 100 today...lots of water in that air.
1. Is this the correct approach to control humidity?
2. Can you ruin the MagicAire air handler by limiting the airflow too much? I'm afraid of adding pressure...backflow pressure...to the system.
3. Can you think of another solution? I thought about routing air to another room that gets hot -- a computer room.