I cannot imagine that you are in such a remote part of the world that there are no competent individuals available.
Originally posted by losiho
a) The unit is overcharged with refrigerant.
Not likely, as more refrigerant RAISES the temperature of the coil.
If anything, it could be undercharged.
This is NOT the only problem, and modifying the charge will NOT resolve the problem.
Perhaps both repairmen are incompetent, and are not sure what the correct amount of refrigerant the unit requires.
Apparently self-evident. Replace them.
b) There are not enough return air grills in the house for the unit. Less likely, imo, as the unit cools adequately unless the pipe is frozen, as described above.
This is like saying "It works great until it quits. So it must not have a problem? Right?"
What do you think CAUSES the frozen pipe?
This is a MOST likely contributor, as airflow dictates how much heat reaches the refrigerant.
Airflow is CERTAINLY VERY HIGH on the list of things that MUST BE VERIFIED.
Simply visually inspecting a coil does not prove it is clean. Pay somebody to take it out & CLEAN it.
Has anybody actually measured the airflow?
I don't mean hold your hand in front of the grill.
I mean MEASURED.
Cubic Feet Per Minute (CFM), or liters per second?
The indoor FAN may be inadequate, too. Is it clean?
c) The non-genuine indoor coils are incompatible with the Pioneer outside unit.
This is a possibility that must be ruled out. I have no way to do that from here. Find a competent contractor. Contact the manufacturer, if need be. Replace it, if necessary.
If it is incompatable, it is a sizing issue.
d) The whole compressor and outdoor unit are screwed, and need to be taken out the ocean and attached to a anchor and chain
THE PROBLEM IS NOT IN THE OUTDOOR UNIT.
Unless it is a sizing issue.
It is suffering, and may be dying, but the indoor section, plus ductwork, is where the problem lies.