Condensation on condensate line

[inspectorwill]

Came across an a-coil condensate line that was developing condensation. The condensation was on about 24" of the PVC closest to the a-coil located in the attic space. Initially, I thought it was a small leak at the bottom of the line and the water was clinging to the pipe from adhesion and following the slope. But I could not pinpoint a leak. I've never come across this before and wonder what, if any, malfunction it could represent since the A/C seemed to be functioning correctly. I recorded an 18 degree drop with an IR camera at the register closest to the coil. It was not exceptionally hot in the attic space about 90-100 degrees and it was well ventilated. Outside temperature was about 75 degrees.

[Garet]

I've heard that some parts of the humid South require condensate lines to be insulated for this very reason. I've never seen it to be a problem in my -relatively dry- climate.

[Jim Katen]

Congratulations! You've discovered "dew point."

[Nolan Kienitz]

Many manufacturer require/request that the first 24-inches of the primary condensate line from the EVAP coil be insulated.

This to minimize/contain the sweating of the PVC.

Of course in Texas in many/most cases the furnace/EVAP coil are located in the attic and the summer temps can range from 130 to 170 degrees and thus a lot of sweating from the condensate line.

Sweating results in the water/moisture soaking through the insulation and then the ceiling sheetrock and then folks freaking out thinking they have roof leaks.

And ... we don't always see the insulation wrap on the condensate lines down here as well.

[inspectorwill]

Thanks Jim always very informative:) I could understand seeing condensation in a high humidity area like Texas but with relative humidity between 40%-60% here in Santa Barbara and a low attic temperature, I would not expect to see condensation develop as I never have before. Just wanted to be sure it wasn't indicative of some other defect like a clogged line or something like that.

[Jim Katen]

Thanks Jim always very informative:) I could understand seeing condensation in a high humidity area like Texas but with relative humidity between 40%-60% here in Santa Barbara and a low attic temperature, I would not expect to see condensation develop as I never have before. Just wanted to be sure it wasn't indicative of some other defect like a clogged line or something like that.

Nah, you just happened to catch it at a good moment. I expect that most of your uninsulated condensate drains sweat now & then under the right conditions of temperature and humidity.