Air Conditioner Condensation Issue

[sjvhvac]

I've got two Trane indoor coils installed and have a condensation issue with one of them. The unit is laying horizontal with the condensation drainline attached to one of the lower threaded openings. The other 3 threaded openings are NOT capped and the lowest one (next to the drain line) is leaking condensation into the overflow pan. Should these three openings be capped ???

[Rich]

I know I capped mine and have had no troubles with it. I couldn't tell you what they are for - only thing I can think of is for connecting multiple coils together. *shrug*