It's like a glass of iced tea. The water coming out of the coil is very cold, it runs into a warm pipe with very hot attic temps, so it sweats. I've seen mine do it some. Make sure you're not getting frost on the copper line entering the coil...that would indicate icing over, which would aggravate the problem big time. I wouldn't think it would sweat beyond a few feet, so a overflow safety pan under the unit should catch any drips. By the way, I removed the p-trap in my line. Lint and crud just settle in the dip and block the flow of water. I did that when it got clogged. Mine flows to the drain lines headed to the septic. I risked getting fumes, but all is well somehow.

Thanks for the reply srercrcr.

I would need to check the copper line inside the unit. I have not removed the cabinet to look at that yet (it will be a big pain based on how the cabinet is installed in the attic). I figured this would be an easy fix but seems to have added some questions!

Anyway, I do have an overflow pan under the cabinet, however, the drain pipe is only over that pan for the first 6-8 inches before it has a 90 degreee angle drop and then down to the p-trap and down the pipe. There is no pan underneath where it is sweating...just the flooring of the attic.

It may be no big deal, but I am not sure why one unit is doing it and the other isnt. It did hit me that I ran the "fixed" unit longer and colder yesterday than the other unit to generate enough water to ensure I fixed my clog. That may be it but I dont think so.

Is your pipe PVS that i sweating also?

Any other replies or thoughts would be great...thanks.

Insulate the drain line.

I would guess that the one that is sweating more is probably for the upstairs and is running more than the downstairs unit....maybe. haha

ditto what brickeye said.

I have the same issue that my drian line pipe coming out of the recently replaced air handler has several drops on condensation outside teh pipe and not leaking from any joints.

is this normal?

I’m in Florida nad its in my garage and you can imagine the temperatures!

Shoule that piece of drain line pipe be insulated somehow?

How and what to insulate the drain line pipe with?

I just noticed this with my system. what do insulate with?

Condensate piping is usually one inch in outside diameter. You can use foam pipe insulation which can be found at Home Depot. There are premade pieces for corners and T connections or just some 45 degree angles. It doesn't have to be anything elaborate. All you need to do is stop the warm moist air from coming in contact with the cold pipe. You can use some tape to seal the ends.

Mike! Thanks a bunch for your reply! Sounds easy enough to do! Thanks again! Cheers!

Thx mike_home. Same type insulation as the refrigerant line.

Yes and the same idea. If you removed the insulation from the refrigerant line it would also form condensation. I lived in an old house in Brooklyn that the humidity in the basement during the summer was so high the main main cold water pipe would form condensation.