bushleague, the jell crap is algea that builds up in the drain pan and drain. This is a constant problem in our climate.Make sure the drain has plenty of drop when leaving the coil.It should also have a trapp installed close to the airhandler and that is normally where it clogs.A good cleaning of the evaporator pan and drain line each year is a must.We install a screw together union before the trapp close to the coil so it can be blown out with high pressure from inside, that way all the crap goes outside.

Bama there are slots in the sheet metal in order to pitch the drain pan toward the drain tube. I would guess the angle is 15 degrees or so, but I'll check it next week. The difficult part is that I need to remove the blower assembly and cut the drain pipe (3/4" pvc), lift the 'A' coil up and then remove the drain pan, (second party involved here, in a closet) which by the way is also inconvenient. There is no trap that I recall, is this in the drain pan itself?

Thanks!

The trap should be outside the airhandler in the main drain line.If you do not have a trap in the drain line the primary pan will hold too much water.The reason for the trap is because the drain line stays in a vacuum when the airhandler blower runs.The blower being above the coil pulls air through causing a suction on the drain line.This could be your hole problem causing the pan to hold water and creating large amounts of algea.