Air Conditioning - Best Way to Clean the PVC Drain

Hi everyone,

I have a tenant whos AC's PVC drain gets clogged constantly! I pull off the convenient cap and blow into it every 3-4 weeks or so, but it doesn't last.

Her filter is clean by the way but she is a smoker; I don't know if that's whats doing it.

Nevertheless, I am thinking of cleaning the straight part of the drain out with a snake I have that I believe will fit. Looks like I'll have to cut the pipe to get in there because the PVC makes a "U" trap just after the water pan and I don't think the snake could possibly get thru there.

Question: What's the best device or way to clean out that "U" or should I just go and buy new pipe and make a new "U"? Also, do you think the most probable place for the continuing clogging is at that "U" or can the 15 foot straight-away be equally probable?

Thanks a million! -Tony

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Unless there is another location where the condensate water can accumulate, sit, and allow stuff to grow it's probably the trap. The straight portions of the pipe (assuming they have the proper amount of slope) are probably dry when not in use. Of course it could clog where the drain line enters the building's plumbing but more than likely it's in the trap. I'd imagine it would be a heck of a lot easier to just cut out the old trap and put in a new/clean one rather than mess with fishing through it but I guess that all depends on how easy it is to get to. If you do replace it, make sure you thouroughly debur the pipe so it doesn't grab on to anything in the condensate, or just use a scissor type pvc cutter that leaves a nice clean edge.

Also, somehting else to consider though it may not work in your installation: If this plugged line has any potential to do some damage, install a float type shut off switch just in case the drain gets clogged again. They're cheap insurance against damaged drywall/furnishings.

Thank you Rick,

Based on your advice, I'm going to replace the trap today.

There already is a secondary pan on the bottom and a float switch. The float switch it worthless however, the secondary pan overflowed and my tenants shoes in the closet got soaked. This equipment is only 1 1/2 years old. I just bought the building 9 months ago.

Thank you for the deburring info too, I didn't think of that. I do have a scissors pvc cutter I'll use.

-Tony

There could be a lot of debris in the primary drain pan. If this is not cleaned, the drain will usually clog again in short order. A good wet vac is an easy way to clean the pan.

The secondary or emergency drain pan should work. It too, sounds like it has a clogged drain pipe. Blow it out, make sure the pan is clean and slopes toward the pipe connection.

Today, I replaced all the PVC from the primary drain pan up to the straight shot to the outside. I tried to snake the straight section but there was a 90 degree bend 2 feet from the drain pan which I couldn't get thru.

Jim, thanks for the reply; the drain pan DOES have gooey stuff on the bottom of it. I failed to clean that part out sicne it isn't near the hole for the PVC drain pipe. Also, the secondary pan is just a pan to catch overflow and it has a on/off float switch, so there' no drain pipe for that one.

The tenant will get back to me on the slow draining but I don't see it improving since the trap I replaced look very good. When I blew into the long straight section to the outside, I had to really blow hard, then after that it was easy to blow. I don't know if something is clogging it or if there's water that's actibf as a trap. I don't know because the water keeps backing up after a week. The tenant has to keep the closet door open and she'
s nice enouigh to check the secondary drip pan every day.

more later ...if anyone has anymore input, thank you!

If you can get to the discharge end & have a wet/dry vac, hook the vac to the end of the drain, dump water into the pan & suck the goo out. Bleach will help cut the slime but be sure to flush with PLENTY of clean water.