How powerful a wet/dry vac is needed to suck out a clog in an Air Conditioner drain pipe?

I was at Home Depot today and wasn’t sure how powerful a vac I needed. Probably not very powerful, but I wasn’t sure.

Are you talking about an Air Conditioner? Why would you use a shop vac? Use a coat hanger.

Can you disconnect the drain pipe? If so, one of these might be a cheaper alternative to a wet/dry vac.

It’s what I use to bust the rare clog in my ac’s drain pipe, since it’s to long for a coat hanger.

When I worked for an HVAC (no slash in there) contractor the techs used a little gizmo with a CO2 cartridge to blow the clogs out. An air compressor would probably work too. Be sure to block off all outlets except the exterior one.

The line goes from my attic to the outside, and the clog is somewhere in between. Doubt a coat hanger will reach.

No, but thanks for the suggestion.

Well, if I have to buy something, a wet dry vac will probably get the most use.

I’ve had good luck with a cheap lightweight plumbing snake in the past. Much cheaper than a wet/dry vac, and likely to see more use.

Have you tried just taking the hose off the evaporator and blowing through it? There’s a good chance it’s just a bunch of muck and slime in there.

I have a mid-range shop vac and it just doesn’t generate that much vacuum. It doesn’t have to. The suction needed to pull water or dust or dirt from a floor is quite different than what you need to suck out a clog (depending on the clog). There’s no guarantee that the most powerful vac at Home Depot will do it. Plumbers use snakes, not vacuums.

Now, if you think you might want a shop vac anyway, get one and try it. Then get a snake if it doesn’t work.

Just saw that you said you can’t disconnect it (why not?)
I think pretty much any shop vac will put out a clog. Just make sure you get a good seal between the drain hose and the vac hose. Might take some Macgivering to rig something up. Maybe wrapping a damp towel around the drain hose to mike it closer in size to the vac hose.
If it’s a complete blockage, even a small vacuum is going to create a lot of negative pressure inside the drain hose. Between that and the weight of the column of water above the cog and I think it’ll pop it right out.

Power and the amount of vacuum pulled by a vacuum are not necessarly related. So pick the size you want.

You may be able to clear the drain with a vac, just try and get a good seal.

I can’t disconnect it because it’s all sealed PVC pipe, but there it a spot with a removable sensor that is supposed to turn off the unit when it detects there’s water from a clog (but doesn’t work). I have been able in the past to blow into that to clear clogs, but that isn’t working now.

Whether or not a vacuum would work depends largely on how “stuck” the clog is. A perfect vacuum on one side and atmospheric pressure on the other side gives ~15 psi pressure differential, which isn’t much compared to other methods. I’d be surprised if the vacuum did the job.

When I googled about clogged ac drain lines, I found several suggestions to suck it out with a wet dry vac. It seems to be a fairly common way to solve this problem, unless people are suggesting it without actually trying it first.

I got nothing to add other than a slight hijack about how relieved I was to discover that I misread your question about needing to suck a DOG out of a drainpipe.

I assume it’s algae, but won’t know for sure until I get it out. I haven’t seen my Pomeranian for a while now, hmmm…

I had a clog in my drain pipe last week and was able to clear it with my shop vac. It worked fine, and it let me clean up the crawlspace under the unit where it had leaked too. Algae buildup can be cleared and then you can run a bleach flush by pouring it in slowly followed by a water flush. If you have a secondary drain(some units do, some don’t) you can get a flexible funnel, open the drain and pour some bleach in through it, let it sit in the collector pan for a couple minutes, then follow it with a water flush.

Enjoy,
Steven

That was one of the ones I looked at yesterday at home depot for this task, thanks for confirmation that this model did the trick for at least one person.

I’m going borrow one from a friend today, but if that doesn’t work out for whatever reason I’ll likely pick that one up.

What is the output of your drain that you attached this to, PVC? How did you get a tight fit? Did you use one of the included attachments, or what?

This. Unless you have insects building a nest it is most likely muck and slime which can be blown out. If you truly want a wet vac anyway then I would suggest one like this with a detachable leaf blower.

You’ll have to duct tape the hose to the drain outlet to get a good seal on it.