Ceiling water spot due to ac sweating.

i had this exact same thing happen last year at this time.

My house was built in the 60s or so.

I had to replace the old duct work with the new stuff today. It fixed the problem.

I wouldnt think you should be having this problem in a 4 year old house

are you in BR?

clean the outside coils

My Lennox unit is 1.6 years old and cools great but the uninsulated drain pipes in the attic are sweating their azz off causing my ceiling to wet. Wrapped rubber/cork tape around pipes and covered with insulation. I need one more roll to finish but that has to wait until it cools down. Will add that the pan was bone dry but unit was sweating profusely.
My hvac guy said the dew point is the reason for all the sweat.

I wouldn't do anything in your attic right now, its dangerously hot, that you don't have to. Maybe put down some sort of pan to collect the water. My guess is your ducts aren't insulated enough and that's the low spot in the duct the water travels to and then drips on your ceiling. If they are insulated enough they shouldn't condensate.

check attic ventilation, thats often the cause if nothing is obviously wrong

often in new houses those cheap motors in power ventilators go bad so check if its working.

those things are famous for going bad every few years

Is the duct work older stuff? A lot of times the older stuff either has gaps in the insulation or gaps in the ducts that allows the hot and cold air to mix.

quote:

---

AC unit is sweating really bad as well as some of my ducts

---

Metal cabinets will sweat not uncommon.
Make sure you have an auxiliary drain pan with a float switch to make sure it doesn't overflow. Also check the drain line from the AHU and make sure there isn't an obstruction at the pan to the drain line.

Duct work will sweat in certain situations if the blown in insulation or insulation in general is touching the duct work. Providing the duct work casing and duct insulation is deteriorated this will also cause sweating.

There is plenty to add but this should point you in the right direction as far as trouble shooting your problem. Hope this helps, I got to go to work.

going to try this, thanks

There's no drip pan under the unit? My entire unit sits on top of a huge piece of sheetmetal that's a drip pan that has a primary drain, a secondary drain and a wet limit switch (which I assume cuts the unit off if triggered). All my ducts are insulated so no condensation there.

My house was built in 2014.