Leak when flushing black water tank

[loislane]

Hey guys - anyone seen this before - water coming out from base of airstream when flushing the blackwater tank?

[dbj216]

I wonder if a piece of road debris banged the plastic drain manifold. It is leaking inside the tank cover, maybe where the drain manifold attaches to the tank. That means it is leaking when ever there is water in it, not just when you are draining it.

Test 1. So if you fill your black tank half full with clean water, and not draining it, does it leak the same way? If not, then test 2 please.

Test 2. Some new Airstreams have these black tank rinsing arms. If you turn that mechanism on, do you see the leak? Let it run for several minutes. If yes, then maybe that's where the problem lies.

Test 3. If you can't get it leaking by not draining, and just running the rinsing wand, then maybe the leak is where the toilet meets the tank. A little leak here would find its way to the bottom of the tank cover, and eventually find a way out, maybe coincidentally while you are draining the black tank. To test #3, with a nearly empty black tank, put a brick or something on the toilet flush pedal and let it run for 3 to 5 minutes. (Don't get distracted and overflow your black tank like I did.) Then look for the leak without doing anything else.

Test 4. Drain your black tank and leave the black tank dump valve open. You would expect the leak to stop. Now run the bath sink only for 5 minutes, see the leak? Now run only the shower for 5 minutes, any leak? Now run the kitchen sink for 5 minutes, any leak. You are testing to see if one of those other fixtures and drains are causing a leak into your black tank area.

You have a brand new Airstream. I should think a warranty claim is appropriate. You're likely need an Airstream RV tech to help resolve this problem.

David

[aftermath]

Is your black tank flush directly above the leak? If so you probably have a crack in it. By all means, take it in and have them look at it if it is still under warranty.

[HowieE]

If you are using city water to Flush the tank there is a back flow preventer just inside the connection. These are a constant problem.

Since the tank flush is a gimmick the easiest way to stop the leak is never use the flush system.

If you want to flush the black tank just as it has stopped flowing lift the drain hose so it creates a trap outside the trailer and open the gray tank valve. While holding the hose count to 10 or 15 then drop the hose and close the gray tank valve. This will put 10 times the water back into the black tank.

[KJRitchie]

More than likely the one way valve up inside is broken. Happened on my 2008 Classic 25fb. I was able to remove it and replaced it with a elbow piece that had the correct threads. I use a back flow preventer on the hose I connect to the black flush. No problems since and I use the black flush a lot.

Since its under warranty the dealer will put the same cheap one way valve and it will be a problem in the near future again. Why does AS still use that cheap part?

Kelvin

[loislane]

Thanks everyone for the feedback. This seems to be happening only with the blackwater flushing. I will take it to the dealer but honestly I trust you guys more than them sometimes. I'll post back with what they say it is.

[Keith Gantt]

Yes, my 2014 23 fc does this. Traced it to the anti suction valve as well as the hose connection to the outside. Haven't had time to find a fix yet. But while looking for this I found the fresh water regulator was leaking ( see pic) tightened the screws and fixed that first.


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[loislane]

Keith - thanks so much - I'm going to the dealer tomorrow so I'll tell them this information.

[AnnArborBob]

Here is a previous thread with some useful information about the anti-siphon valve for the black tank flush. It's an easy fix but since you are under warranty definitely have the dealer fix it.

Despite what one previous poster said, it is a very useful feature and worth using every once and awhile.

Also, blowing out this valve with compressed air is often overlooked during the winterization process so beware!

http://www.airforums.com/forums/f444...ak-124696.html

[SilverGate]

I have used the black water flush every time we have been camping for the past 7 years and this leak has only happened once when I did not have the water hose pressure turned up to the proper level.

As a side note, when connecting the water hose and turning on the campground faucet, do not quickly turn it on full blast or it might break the internal black flush system parts. I turn on the hose and gradually increase the water pressure to where the hose feels firm.

[m.hony]

I had a leak while flushing the black tank. I had overlooked the black tank flush valve during winterizing. The valve is in the bathroom cabinet in my trailer.

[loislane]

Hey guys,
Just got Homer back from the dealer - they replaced the black tank flush tank valve. Really appreciate all your help!

[Keith Gantt]

Finely pulled apart and what do I find... Airstream fails again. No gasket on one end. 10 cents for gasket.


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[dneff01]

How does one get access to those valves ?


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[AnnArborBob]

Originally Posted by dneff01

How does one get access to those valves ?


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On your unit (a recent 27' FB) the anti siphon valve for the black tank flush is at the back of the wardrobe. Remove the little "step looking" thing at the back of the wardrobe by removing the dozen or so screws and two pieces of laminate and you'll see it soon enough.

[Taroni]

I have a 2014 Sport 22' and have hooked up the sewer flush three times. It has leaked all three times. My leak is much worse that yours. Today I turned the water on very gently and it still leaks out the bottom of the trailer. Will call Holiday World tomorrow and arrange for a repair.

[dneff01]

Has anyone used this brass one way check valve as a replacement for the plastic piece ?


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[Taroni]

Found a solution to the problem: Traded it in for a 2016 Flying Cloud.

[Boxite]

Originally Posted by Taroni

Found a solution to the problem: Traded it in for a 2016 Flying Cloud.

Well...that's ONE way to sell a new trailer... sell a defective one and then later take it back in trade for some simple fix...
The backflow preventer is a building code requirement for hooking up to city water to flush the black tank. This is because code-writers believe you are likely to leave your hose hooked up and the valves open and let a germ climb backwards into the city water supply. NOT LIKELY to happen!
Since I only hook up to my own private well...and/or a campground supply...with a dedicated garden hose.... and since I only do so to pressurize the flush system and never leave that hose connected unpressurized....it's NEVER GONNA HAPPEN that a backflow preventer would prevent anything except the flush-system's proper operation.
So... after I found the insect nest in the backflow preventer that blocked the flush system from working... I removed it and replaced it with a "shark-bite" elbow, which was a very simple matter: Cut the PEX tubing, insert the "shark-bite" elbow... and FLUSH anytime/everytime with no problems.

[airstreamz]

2010 Flying Cloud 20 here, this connection is under the bathroom bench, looks like I need to remove the benchtop to gain access.

I can see the leak through the side panel access, but is too tight to work on. I hope it's a simple gasket issue. Is there an easy way to remove the bathroom benchtop? it appears I have to disconnect the waste and 2x tap hoses, before I can slide it out?