A/C leaking condensation

We have two AC units. One downstairs and one upstairs. The upstairs unit is putting out a ton of condensation, which leaked through to the ceiling below. It did this before a few years ago and the tech who came out said it was because the filter was clogged. I recently changed the filter, so it's not that this time around.

Both times it was unusually humid. We live in the high desert. I suspect it was an ongoing problem for the previous owners. You can see water damage in the closet where the unit sits. I don't know much about AC, but is there some part that's supposed to handle the condensation that's not working? Need to find a fix for the AC before I fix the ceiling.

 

I know of no filter used on condensate. Usually the pump in the sump quits working. Most often it is caused by snot (biological) growth in the tank that gums up the switch and pump. Cleaning usually gets it working again. You also want to check your condensate line, and especially the trap, between the AC and condensate sump for clogs.

 

The filter that was refereed to is the main air filter. If it gets clogged it can create negative pressure causing the condensate to not drain properly out of the drain line.

A dirty coil can cause the same problem.

Typically an overflow pan is installed under the entire unit where if it leaked it could cause water damage.

There are three drain ports in the circled assy.
Are there three where the drain is actually connected ?

 

Here's where the drain comes out. There's definitely no drain pan installed under it. I'm almost positive this house originally had a swamp cooler and they had this installed in what used to be a closet when they converted to refrigerated air.

One other thing I noticed when I pulled it apart, there was a small gap where the filter had slipped through the hole at the far end. That may have happened when I installed it and didn't notice. Could that gap cause the same problem?

 

I put a new filter in and made sure it was properly seated. I've run it for a couple hours now and there's no condensation. Not sure if that has anything to do with the filter though. The outside humidity was 50% when I had a problem, which is rare. It's currently 40%, which is still high for New Mexico.

How would I access the coil to clean it? Or is that something I should even attempt? I called around and the soonest I can get someone out to look at it is the end of next week and we're going to be hitting the high 90s between now and then. So hopefully I can get it figured out on my end.

 

I checked again and it was leaking again, but I think I'm making some progress.

The PVC was loose where my finger is pointing. Water was pooling below it. At this point, I couldn't hear any water flowing. I pulled the connection apart and water came gushing out. I quickly pushed it back together and could then hear quite a bit of water running through the pipe down to the pump until it kicked in.

After the water stopped running, I pulled the pump apart and cleaned out the gunk and put it back together. Not that that had anything to do with my problem. But figured it couldn't hurt. So now I know (or think I know) it's a drainage problem related to how the drain is plumbed.

Is there any reason for the pvc to dip down and back up in the second picture? I think that could be causing water to back up into the unit. But as I'm sure I've demonstrated, I don't know much about anything.

 

That dip is called a trap (mentioned in post #2). The drain pipe is a direct connection to the conditioned air plenum. The trap holds a bit of water just like the traps in your drain pipes. It prevents the AC from blowing your conditioned air out of the drain pipe.

The fitting you said was leaking. Is it glued in place? Because clogged drains are somewhat common I don't like to glue all the joints. I will just press them together. If yours is leaking maybe you can push it together more to stop the leak. You can also glue the joint though it makes cleaning the circuitous drain pipe more difficult. I have also used a rubber boot with hose clamps instead of glued PVC. If you buy a dishwasher drain hose adapter the rubber boot can cut to size to work on a AC drain line. Then it's water tight and easily removed for cleaning.

 

It's not glued together. But I'm not sure if that was the source of the leak. Or if water was so backed up it was leaking inside the unit. I was able to push it back together tightly though.

After I pulled it apart and pushed it back together, I could hear water running through it for about a minute, so there was quite a bit backed up. Maybe there was some gunk in the PVC blocking it. Or could an air bubble have caused it to back up?

 

I took the drainage pipe off again, blew compressed air through it and ran water through it with the hose. Put it back together and water is running freely to the pump. The reservoir filled up pretty fast. Turned it off and pulled the pipe off again. Only a trickle came out. Nothing like the gush of water like before. So seems like it was just clogged. Hopefully that fixes that and I'll start flushing it out every spring when I change the filter.

Just to be safe, is there an easy way to waterproof the area under it? Thought about using some silicone roofing sealant, but I suspect there will be fumes. Which I probably don't want blowing through the house.

 

If you want to provide some waterproof protection I would consider something like EDPM pond/shower liner plastic. It's thick and durable so you can be rough stuffing it into place. Fold the sides up to form a pan and you can glue it in position or nail up several inches on the sides. Then put a battery powered water alarm in there so you can wake up at 3am wondering what the beeping sound is.

 

Thanks. I'll give that a try.

 

It sounds like the trap was plugged and you cleaned it. Good job.
Be sure to add that to your seasonal chores.

 

Yep. I’ll pull it apart and clean it every spring when I change the filter. Now the fun part is trying to waterproof the area under it. Might have to recruit my seven year old to fit through the air intake.