TheSamba.com :: View topic - AC condensate drain tube tip and interior flooding

Sun Jul 07, 2013 8:09 pm

I took a few pics of these drain tube tips for Todd who is having condensate flooding issues and also noticed these tips have been removed from his van. He brought up their function as important and my thoughts were no big deal that they are missing. Then a bell rings as to pressure tests a few folks here have conducted with respect to air flow in the upper engine air intake grill area. I'll let Mr. Wanderingman take it from here :-). He may have uncovered an important small detail that could cause strange flooding issues if the drain tubes have been compromised...

Sun Jul 07, 2013 8:29 pm

Reminds me of 60's vintage oil breathers which dumped onto the street, they had that same type of rubber valve on the end.

Sun Jul 07, 2013 9:09 pm

So the story goes...

I bought the Westy about three weeks ago(my first). A/C was low on Freon(R12 system). I found a guy to charge it up and it was running fine(on #4 fan speed only) and blowing cold. I thought everything was fine with the exception of the fan speeds 1-3(but that's a separate issue). However, as I was driving down the highway with it blowing cold on high speed, I noticed in the rearview mirror water pouring out everywhere around the evaporator housing. After reading a little about it on here and getting feedback from Denwood, I just figured the drain hoses were plugged. Rather than trying the cleaning route from outside, I was going to have to pull the housing anyway to check the fan motor resistors so I decided to wait and check out the whole thing once the housing was removed.

I did that a few days ago. Hoses were free and clear. Drain pan was intact without cracks. What now??? Then, last night I just happened to pop in a series of Technical Movies(on VHS) that I ordered a few weeks ago from Terry Kay. Behold, my hoses are missing the valves which are said to be necessary, according to the technical video, but without real explanation as to why. After discussing it with Denwood, this thread has started. Due to other concurrent projects and timing, I will not have the evap housing re-installed for several more days, therefore, I won't be able to test the drain hoses at idle to see if they drain. Any further input you guys have until then would be appreciated.

Tue Jul 09, 2013 5:37 pm

My drain tube ends don't look anythink like these photos. My tubes had a cap on the end (same material as the tube) with a pinhole in the bottom. When I started getting dripping inside the van, I cut off the cap, blew out the hoses, and have not had any issues since. If there is an overpressure condition at the tube end from airflow at the rear vents, it is not affecting my drain tubes. I wonder what the airflow path actually is from the rear vents - the passenger side feeds the engine air intake, and the driver side, nothing. So my thought would be airflow forced down into the engine bay, causing a negative pressure vs positive pressure at the drain hose, facilitating better drainage, not reverse condensate flow. I guess it's possible - but I haven't had the issue with mine - and no more flooding with the tips removed.

Tue Jul 09, 2013 9:55 pm

That's a duckbill valve and it is commonly used to prevent a backflow condition. I have'nt had to delve into a/c condensate problems on my van yet, but would agree that some form of differential pressure is required to open it.
Could possibly be used to keep road grime from entering the drain end.

Tue Sep 24, 2013 7:19 pm

Down south, if you keep those lines open (as in cutting off it's tip) dirt dobbers will move in. Clog. It happens more than you'd think.

My issue with this system: the plastic adaptor this hose connects to on the drain pain itself has cracked and is not longer connected. Both sides. Due from poor design and improper removal. Thus the condensate dripping out of my evap housing. The humidity here In Houston creates tons of condensate.

I tried to buy a new drip pan. No luck. After searching for aftermarket & OEM, finally found a junk yard in Arizona whom sent the wrong one. :(. Ho-hum.

Now that I have it back together with my jeri-rigged setup, I think I'm low on freon. Autozone doesn't sell R-22 recharge bottles. Go figure.

Any pointers for me on what to do: low freon & condensate issue/broken drip pan.

Anyone sell a retro-mod evap housing that's packaged better than VWs OEM. I've got an '87 vanagon tin top. ...luckily were headed towards fall. But next summers going to be a sizzler!!!!

Thanks.

Wed Sep 25, 2013 6:09 am

my drain lines had those fittings and mine was still leaking water out of the vents.

took a look at the AC unit and they drain lines were not even hooked up to the drain pan under the evaporator. Whoops.

Check yours.

Fri Aug 18, 2017 7:56 pm

Had an experience with this today. Headed to the southeast from the northeast for the eclipse. First long trip with the redone A/C. I was sure I'd cleaned the lines but water started dripping out of the upper cabinet right after we abandoned the interstate after a long stretch. I concluded that the pan must be overflowing. Verified it when I found a place to pull over and look at it.

I figured that the gunk must have found it way into the tubes, which was hard to believe, since I removed all old foam and scrubbed everything squeaky clean.

Pulled the vent grilles and found those ends to be pretty tightly closed and just dripping. Squoze (squeezed) the end to open it and a geyser came out. No dirt or debris. I'm guessing that the rubber end is supposed to open up under a certain amount of water pressure but the old rubber is too stiff????

In any case, it was too hot and humid to do without A/C today, so I took a razor blade a cut a tiny hole in each tube end, right in the center of each opening.

Sat Aug 19, 2017 4:46 am

Duckbill valves are not designed to open in air currents.

They are designed as check valves, one way valves to allow liquid flow (sometimes air/gas) in one direction and to keep out anything trying to enter the pipe they are connected to.

For example, Ocean outflow pipes, they keep the wave action and sand out yet allow pipe flow to exit.

They open with the weight of the liquid pushing against them.

In our A/C condensate use, it is simply gravity operated.

Sciroccojim probably nailed it with his theory of old stiff rubber holding in the water.
This is probably my problem for I will sometimes get water dripping on the rear bed area and I KNOW that the drains are clear and connected.

We need to locate a source for new valves that fit on these drain tubes.
If you leave the tubes opens, all manner of insects will make the tubes their home!

A link that describes the valves......

http://www.minivalve.com/newsite/index.php/en/by-type/duckbill-valves/how-they-work

This site also sells the valves, I'm going to check into order quantity and prices.

Dave

Sat Aug 19, 2017 5:41 am

Also for consideration.
If there are any lengths of the tube lower then the rest where water can pool inside the tube chances are you are going to get mold/fungus which will grow and block the tube. So you want it able to flow at all times.
If the vehicle is being driven daily the g-forces are sloshing the water around so the tubes shouldn't really have water pooling in them, but it still can happen.
They make special little tablets you could buy that will slowly (30 days) and said to kill fungus in condensate drain tubes. Really-how often are you going to open your AC to do this?
Or you cold pour some bleach down the tube occasionally. If the tube gets blocked the fungus is not that strong and it can be blown out with a little bit of compressed air or sucked out with a vacuum on the end of the tube.
It is also a very idea to spray some Lysol or other disinfectant into the air intake of AC's to kill any mold built up on the evaporator fins.

Think of Legionaires Disease and moist air ducts and condensate drain pans.

Sat Aug 19, 2017 6:15 am

cut it and be done..

Sat Aug 19, 2017 6:28 am

I get the drips on long road trips. I've considered fixing a short piece of
toothpick in the valve just to keep it always a ~tiny~ bit open...???

<shrug>

- Dave

Sat Aug 19, 2017 6:36 am

Morning fellow bus drivers!

When we refurbished the AC in the Carrot those drain lines where extended down to the bottom of the D pillars and the valves were deleted. The new drain tubes are clear and the condensate drips easily onto the ground, not into the bottom of the d pillar.

Sat Aug 19, 2017 6:44 am

I was thinking of deleting ours and possibly adding some mesh on the bottom, as well as extending them.

Sat Aug 19, 2017 2:20 pm

not sure this will help, but a Volvo 2/7/9 series flame trap and booty may slide over the existing tube. it will let water out and keep bugs from getting in.

this was a "fix" for spiders getting into the tank vent on 850's S-V70's /P2 cars and building a web that clogged the system

Sat Aug 19, 2017 7:42 pm

Not sure if these have been posted already or if I missed something. But I just finished installing and overhauling a stock AC system in my van. I installed these drain valves from Van Cafe. They were brand new soft rubber and fit right over the stock drain lines. I added a little silicone sealant for good measure. Just returned from 1,000 mile trip which saw plenty of AC use. The evaporator stayed drained properly, with not a drip from the evaporator housing. I know these are pretty similar to the stock valves posted above, but they are working very well for me.

http://www.van-cafe.com/page_806_118/ac-evaporator-case-drain-valve

-Jeremy

Sun Aug 20, 2017 6:13 am

ClarksuperVan wrote: ... these are pretty similar to the stock valves posted above, but they are working very well for me...

Thanks, good to know and at a whopping 2 bucks apiece pretty much settles the question of what to do.

I have never messed with mine so tell me -- if I remove the black plastic side vent should I be able to just reach back in there and get hold of it, pulling the tip far enough out for inspection? Is there a drain on each side of the van?

Sun Aug 20, 2017 10:11 am

Hey, Volkswagen also used those rubber valves on passats with sunroofs to drain the water that gets in under the sunroof with the outlet in both front door jams. The rubber fuses closed over time and your car floods (arg! - ask me how I know). Had to force both valves open - never another problem!

Sun Aug 20, 2017 6:38 pm

Wow, really great to see that new ones are available. They're on my list. Thanks for the info.

Ahwahnee wrote: I have never messed with mine so tell me -- if I remove the black plastic side vent should I be able to just reach back in there and get hold of it, pulling the tip far enough out for inspection? Is there a drain on each side of the van?

Yes, easy to get to. One on each side.

Sun Aug 20, 2017 8:14 pm

In my experience flooding of the evaporator tray is caused when the black foam in from of the evaporator crumbles. A much better solution rather than foam is stanless steel mesh. The mesh needs to be a bit finer than screen wire and will need a few creases in it to hold shape. This is what is used by Mercedes and others. Removing the rubber tips and extending the plastic lines also works. The valves are there do to a very low/non-existent risk of co being pulled into the vehicle. By extending the drain lines into a low pressure area that potential problem goes away. It always amounts to cost and regulations.