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Old 04-24-2009, 02:19 AM   #1
2 Rivet Member
2012 20' Flying Cloud
it depends , changes frequently
Join Date: Nov 2007
Posts: 25
Black tank flush uh-oh

I've been using the black tank flush on my 20' 2007 Safari SE regularly for the past year with no problems. Worked great. Then I let a few weeks go by without using it (sometimes dump stations don't have hoses with threads!). When I was able to use it again, a boatload of water (clean, thankfully) came flowing out from the underbelly pan - a veritable waterfall! The gushing stopped before I was able to turn the water off. I checked the inside for a flood and it looked okay, then tried the flush again. The second time, there was no waterfall, and I could hear the mechanism just barely working with the little bit of water that was able to get through.

From the exterior, there was no way to see where the gushing water came from or traveled to. In the interior, I removed the panel behind the toilet and could barely get my hand down in there, but felt the floor and insulation to be wet. I also could see that the "vaccuum valve" - or whatever that vertical inline part is - was leaking slowly. So I bombarded that area with de-humidfiers and heat the best I could. And sprayed it with Lysol.

The only thing I could guess was that the flush was blocked up and it forced the fresh water out SOMEWHERE but in that process cleared out enough of a path to let a trickle in so it didn't gush anymore.

My trailer is still under warranty, and I believe Airstream will cover this repair, but it will be 3 months before I am able to get to Jackson Center. So here are my questions, if anybody can help with this:

1. WHY the big flood of water from the bottom pan, then no more? ...and WHERE did/could all of it go before draining out of the bottom pan? Do I have to be concerned with mold and floor rot?

2. I can only access a very small area in the bathroom behind the toilet, so I can't tell where all that water broke free, and where it potentially traveled to - do I have a potentially bigger problem here if I continue to use the tank? I won't use the flush anymore, but is it still okay to use the toilet? Where does the flush mechanism enter into the black tank? Would it be a good idea to monitor the level of the tank and not go beyond a certain fill point?

3. Any idea what is involved in fixing this?

4. Since I can't use the flush to clean the tank, and since I hope to still be able to use the toilet, is it enough to fill the tank with fresh water after dumping by just using the toilet flush pedal, then dumping a second time? Then, when I drive, fill it up halfway or so (with the flush pedal), dump some enzyme-cleaner in there and let it scrub away while driving?

It's been a couple weeks since it happened, and all seems okay now - well, actually, the front wood panel that forms the "platform" that supports the toilet shows slight warping at the seams, which may or may not be associated. I am concerned that maybe waiting 3 months and still using the toilet will cause a greater problem that I cannot see. I probably should have posted this as soon as it happened.

Any info/advice/suggestions? Thanks in advance for any help.
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Old 04-29-2009, 03:04 PM   #2
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kennethowens's Avatar
1975 Argosy 24
Malakoff , Texas
Join Date: Apr 2009
Posts: 490
Consider.....remove enough rivets to get to the drain valve.
Consider....remove the two bolts that hold the toilet down and check
the seal.

Andy at Inland RV.....he is usually in the forum....find his email.
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Old 04-29-2009, 04:41 PM   #3
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2012 25' FB Eddie Bauer
Vintage Kin Owner
Virginia Beach , Virginia
Join Date: Sep 2004
Posts: 7,361
Black Tank

First you can go to any RV store - or possibly even WalMart - and find a "thingie" that will let you flush your black tank through the toilet bowl drain opening. New ones are rigid plastic - about 18 inches long, with a nozzle pointed 90 degrees to one side. I've seen older ones made from brass. You put them onto a standard garden hose, insert into the toilet by stepping on the flush valve and spraying away. It helps to have the fan on! It helps to put Vapo-Rub under your nose too.

The flush king is a bit wimpy and if you let your tank get really full it could have clogged. Flushing from above should get your tank empty and clean, then you can move on to diagnosing the flood in the flush king.

Definitely you're going to have to pull at least part of the belly pan. My first guess would be that a poorly connected fitting gave way under the back pressure. It isn't going to fix itself now that it's leaking.

Oh, the enzymes would help but aren't as fast as simply using a manual flush nozzle from above. Let's face it, if the leak is at the point where the flush king enters the tank, you might have to get all the way into the tank... you want it as clean as possible before you remove the flush head.

Today is a gift, that's why they call it the present.
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Old 04-29-2009, 06:14 PM   #4
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2007 25' Safari FB SE
North/East , New Jersey
Join Date: Nov 2006
Posts: 348
Silversnail.....We had a similar problem with our 2007 25' when using the No Fuss Flush when the water started coming out of the black plastic containers under the trailer. I tracked it down to water coming out of the top of the clear plastic Lakeview RV Supply Model 1000 combination check valve/ and anti-siphon valve mounted just behind the water supply fitting on the outside of your trailer. The valve is constructed with the top of the valve being open to the inside of your trailer. When you hook up the water supply to the No Fuss connector the water pushes up a nylon plunger with a rubber seal on it to prevent the water supply from entering your trailer. When you shut the water off, the plunger drops down and prevents any siphoning of waste water to the supply hose. I replaced the valve as a precaution ($25.00 from Lakeview/$47.71 from Airstream) but think the leak may have been caused by some dirt on the seal, allowing the water to flow out the top of the valve and work its way down to the bilge area where the tanks are located. Fortunatly it didn't run along the floor and mainly went down to the bilge. As a precaution, I'm going to include the valve on my list of items when winterizing the trailer. I set up a fan and let it run for three days to make sure all of the water dried up.
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Old 04-29-2009, 06:22 PM   #5
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2006 30' Classic S/O
Currently Looking...
Mohrsville , Pennsylvania
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Take a look at this post and you can see how yo get at some of the plumbing for the black tank flush mechanism.

Carl, Elaine & Finn The Beagle
2006 30' Classic W Slide & Limited Package Katarina
2006 GMC 2500 HD 6.6 Turbo Diesel Crew Cab 8' Bed
AIR #14487
NQ3U (was KB3UOM)
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Old 07-24-2010, 09:25 AM   #6
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2008 27' Classic FB
Burkburnett , Texas
Join Date: Jul 2010
Posts: 985
Leaking backflow preventer

I just had a similar situation with this device. Found that the outlet nipple was cracked. Whenever I used the tank flush, clean water was dripping through an opening where one of the LP lines entered the belly pan. On the 27' Classic (2008) it is accessible by removing 9 screws to lift out the floor components of the closet. The Lakeview Model 1000 is found atop 2 plastic pipes that are attached to the side wall with a clamp and a screw. The device appears to have 2 functions: The obvious is to prevent water from the black water tank backing up to the connection to prevent hose contamination. When the hose is disconnected, the vertical piston drops and allows air in to drain the assembly and inlet line presumably to make it freeze proof.
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Old 07-26-2010, 06:55 AM   #7
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2014 27' Flying Cloud
Viera , Florida
Join Date: Oct 2006
Posts: 1,236
This happened once to me with our 23' Safari. It turned out that I didn't have the water all the way on. The valve won't close until there is a certain pressure in the water line. After I shut off the water and turned it on again full, the leak stopped. Never have had trouble with it again.

At a visit to JC after this incident, the service center confirmed that this was what happened and how it works.

Randy & Pat Godfrey
Florida Airstream Club (027)
WBAC# 1212 - AIR# 17017
2014 27FB Flying Cloud - SilverCabin II
2018 F-150 Platinum - unnamed

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Old 07-26-2010, 08:48 AM   #8
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2006 19' International CCD
Olathe , Kansas
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06 Bambi

This happens to me Saturday. I didn't flush it yesterday but will try again on Wednesday and let you know how it works out. Thanks for the info!
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