Black tank flush leak inside 2506S

[Fbuoni]

I have a vacuum breaker or air admittance valve leaking inside when I tried to flush the black tank. Thankfully someone was inside and I shut the water off. I ask why is it there other than for freeze protection. Has anyone removed this. I was thinking just blow it out with air at the end of season.

[Chris Pastuzyn]

Basically it's for in case black water just happens to get back into the water line ,this has a back flow valve built in, Mine failed out of the box ,Would recommended getting a brass one to replace it, Watts or T&S makes them,

[5picker]

It's there so in the event of using the black tank flush and the water supply line has a catastrophic pressure failure allowing the water in the supply line to back-drain quickly, the valve doesn't allow black water from the tank to be siphoned back into the supply system via suction.

This all assumes the level in the black tank is high enough to cover the flush nozzle. It 'usually' isn't but you never know as I've seen some folks hook up the black tank flush and start adding water before they ever pull the dump handle for the first time.

[phipps33]

Mine failed the first time I used it and flooded the camper. A couple quick connect fittings and a piece of PEX and it won’t do that again.

I understand the purpose of it, but it would take a very specific set of circumstances for it to ever backfeed into the water supply. There are also external backflow preventers that can be put on the supply hose.

[DustyRoads]

Mine failed and replaced with a different brand. I had the same issue as you. When I took it apart there was a bug in it.
I use it sometimes but I don't trust it unless I have someone in the trailer. I am mostly using a black tank wand to clean out tank. I especially clean it out thoroughly before going dry camping.

[Diverman]

Ours started leaking on the third usage of our new camper. I was lucky to catch it, my wife was putting things away in the bathroom and she seen the water leaking. I removed and put in a brass elbow, then put a inline anti siphon on the hose end. Has worked flawlessly, and not worrying about flooding my camper. I have talked to 2 other people while camping that have had the same issue, seems like a common problem.

[itat]

Originally Posted by phipps33

Mine failed the first time I used it and flooded the camper. A couple quick connect fittings and a piece of PEX and it won’t do that again.

I understand the purpose of it, but it would take a very specific set of circumstances for it to ever backfeed into the water supply. There are also external backflow preventers that can be put on the supply hose.

For the sake of your fellow campers, please do not use the black tank flush without some kind of vacuum breaker or check valve. Its so simple and inexpensive to just use this hose bib vacuum breaker outside on the hose you’re using to supply the flusher.

https://www.homedepot.com/p/Everbilt...Z4EB/205815672

The wands that you stick down the toilet all have a built-in check valve.

[Fbuoni]

Thanks for the link. I wouldn't use the black tank flush without a back flow now that I know what it is for. But a external is a must. I normally dump at the camp ground but flush before putting it in storage. Where I store it they have a dump station and I can take my time. But that said its in a room not accessible with the slide closed. Recipe for disaster. My failure was caused by a stink bug. This past weekend they were out in droves. I battled them all weekend �� and they won!