Black Tank Flush - Water leak under bathroom sink

[Brymac]

My wife and I were packing up our 2016 Roo 23ikss today and as part of usual process, I had hooked up a hose to flush the black tank.

After a few min of flushing, my wife began screaming from inside the trailer that we had water running onto the floor. I quickly shut the hose off and went inside to find quite a bit of water under my bathroom sink, which had also run under the wall, and soaked into the carpet beside the couch.

Couple of questions:

1) I've read a lot of material about the black tank check valve being faulty. Is this something my local dealer can likely replace? I'm not in warranty, but ultimately not ultra handy either so hoping I can have someone do the work.

2) assuming #1 was in fact the issue, would it be fresh water which leaked? It didnt have a smell, so assume it was.

3) our trailer is stored outside and I've left the max air vents open and cracked a couple windows, as well as added a few packages of damprid near the wet areas. Should I be concerned about much more significant damage?

Sincerely appreciate any help or direction this community can provide.

Many thanks,
Bryan

[whirledpeaz]

It sounds like the air admittance valve/vacuum breaker is bad or "stuck". Not uncommon and not terribly difficult to replace.

[Miskibum]

I had this happen to me two summers back. Turns out the washer with strainer for the be flush connection was bad. Some water from the hose was blowing past the washer into the RV. New washer fixed it.

Funny thing is that when the RV was new in 2015 we found a tiny bit of moisture in a small cabinet that we wrote off as condensation. Turns out it was probably the same issue going back to the PDI.

[5picker]

LOTS of prior threads on this. One of the most discussed topics on this forum.
The inexpensive plastic valve often fails.
Many replace with a brass valve by Watts.
You'll be looking for something like this...

[davidfraticelli65]

Just to add to the above observations. Same situation for my brand new 2019 FR Cherokee MKSE. Found out about these bad valves plus I also found out that they need to be installed straight up and down like the photo in 5picker's post above. Mine was listing at a 90 degree from the factory and spewing water out from day one. I replaced it with a better valve and now have it installed correctly . Hope this is useful.

[handymanj56]

I replaced mine... Same thing was leaking.. got a brass one from Amazon

[CedarCreekWoody]

Originally Posted by whirledpeaz

It sounds like the air admittance valve/vacuum breaker is bad or "stuck". Not uncommon and not terribly difficult to replace.

Not likely. The AAV is on the drain line, not the pressurized water line.

[5picker]

Originally Posted by whirledpeaz

It sounds like the air admittance valve/vacuum breaker is bad or "stuck". Not uncommon and not terribly difficult to replace.

Originally Posted by CedarCreekWoody

Not likely. The AAV is on the drain line, not the pressurized water line.

While the terminology may have not been entirely correct, the black tank flush anit-siphon/check valve DOES allow air admittance to break the backflow if the situation arises.

Just sayin'

[whirledpeaz]

Originally Posted by 5picker

While the terminology may have not been entirely correct, the black tank flush anit-siphon/check valve DOES allow air admittance to break the backflow if the situation arises.

Just sayin'

Thanks! You knew what I was getting at. I am not nor do I ever want to be a plumber.

[emm-dee]

Probably one of the easiest maintenance tasks on an RV. Get a new one from Amazon. No tools required unless the fitting is super tightened, meaning you’ll need pliers.

https://www.amazon.com/JR-Products-5...s%2C156&sr=8-1

[CGK]

That is a familiar story - same exact "symptoms" we experienced when the blackwater flush anti-siphon valve/vacuum breaker failed on our previous TT. My wife noticed the leak quickly, as it appears yours did.....other than losing a bunch of toilet paper we had stored in the vanity, we had no permanent damage - and hopefully you will not have any issues either. You will want to be sure everything dries completely by providing as much ventilation as possible. And yes, a dealer can install a new breaker for you, but it will cost a bunch and you can almost certainly do the work yourself. For me, the most difficult part was working in that tiny vanity, where I could only get one hand on the plumbing. But that's typical when working in TTs, so to be expected. Beer helps, as does music. Suggest you replace with brass, so you're not just installing (or paying to install) another "will-fail" device. Good luck!