Received a call at the Friedrich wall unit that is located closest to the outside wall over the bathroom door was leaking water, upon arrival I confirm that water is dripping from there. I opened the bottom of the unit and found that the water was not leaking from the drain line, but it was dripping from the main drain pan and overspilling into the machine. I traced out the drain tubing into the basement and found that the poly tubing had a sag in the line before it went into the PVC drain line which was causing a double trap. This was causing an airlock and preventing water from draining out of the pan. I adjusted the drain line and was visibly able to see all of the water drain from the unit above and outside. There is still moisture inside the system which will probably drip out, but it should stop within 24 hours.