Black Tank Flush Check Valve

[Derby6]

I think the Black Tank Flush Check Valve failed on me. Lucky for me all the water was caught in storage container lids and I found first thing this morning. Just ordered replacement on Amazon and should have it Thursday.
Do any of you (or is it OK) to leave my 2nd hose connected to the flush input all the time? I have so far and no issues until now. But is seems my splitter shutoff is leaking a drip (and I mean drip) and I am thinking that maybe that drip/leak is keeping partial pressure on the valve hence it leaks. It doesn't seem to leak when I am actively flushing the system. Only after I shut it off.

[RMcNeal]

Mine leaked shortly after we purchased it new. I ended up cutting it out and coupling the pex in the basement directly through to the tank flush, then I added a hose end back flow preventer/vacuum breaker on the inlet in the wet bay. If you ordered a direct replacement of the original plastic one, it will eventually leak also. You may not want to bother and just return it and eliminate it as many of us have done.

[Derby6]

Thanks. Agree, but I’m no plumber and don’t completely understand.
I had a thought of eliminating and straight piping but figured it had a reason to be there.

[RMcNeal]

It's only real purpose is to prevent any black tank contents from entering the fresh water supply and to provide a vacuum break to relieve pressure when the flush is not running.
Both of these functions can be accomplished with a hose end back flow preventer/vacuum breaker on the inlet in the wet bay.
It is extremely unlikely that it could happen anyway, but for just a few dollars you can add the back flow preventer in the wet bay and it screws right into the inlet where the hose screws in.
In my case, the valve was plumbed under the bathroom vanity sink, so I just followed the pipes into the basement, cut the elbows out that sent the pipe up to the valve and back down again and connected them at that point. You could even use a shark bite coupling if you don't have a pex crimping tool, but I prefer to crimp the connections.

[jsmitfl]

The only problem leaving the hose hooked up all the time is if someone wants to play games or just by accident turns it on and you don’t know it the tanks going to fill and flood your house. I leave mine hooked at the spigot but not the trailer.

[RMcNeal]

I have elbow connectors in the wet bay that have on/off valves on them so I just turn that one off in the wet bay (which is typically locked). That keeps anyone from turning on the black tank flush externally.

[jimcol]

Enough people on this forum over the years have reported damage to the black tank from getting distracted when flushing and over filling. Some, not many have reported pranksters turning the shutoff on and causing damage. You don't need to flush the tank every time you dump it unless it's going directly to storage. (I know some people do, what a waste of water) For these reasons I never left the flush hose hooked up except when flushing the tank.

[Carl n Susan]

Rather than a splitter and two hoses running to the RV, I just use the outside shower hose in the convenience center when I need to flush the black tank. I have quick disconnects on the shower hose and the black tank flush connection. That way it takes no time at all to connect, flush, and disconnect, all while sitting right there and not walking away (when bad things tend to happen).

P.S. I use quick disconnects on my shore water hoses too. The quick disconnects on the shower hose are reversed from the quick disconnects on the water hoses. That way you can't accidentally connect the shore water to the black tank flush or the shower hose to the shore water inlet.






Vs. this style

[Derby6]

Funny Carl. I was just thinking about that outside shower connect. And I just bought a quick connect today. Trying it out.

My splitter is 100% leaking and that was my issue.

[Daryles]

Some people have plumbed the connections

[Derby6]

WoW. Ow that’s a redo. Lol

[Derby6]

Originally Posted by jimcol

You don't need to flush the tank every time you dump it unless it's going directly to storage. (I know some people do, what a waste of water).

I get what your saying, and try and not be wasteful, but always flush. Often surprised at what I get out after the initial dump. And I don’t dump until it’s 2/3 or so full.

[beeje]

The only reason that ridiculous backflow valve is in there it's because they're lovely government mandated it.
Do yourself a favor and bypass it by cutting the lines in the basement and plumbing them together before you flood your camper

[BB_TX]

You are correct it is government mandated. And for good reason. To protect the public water supply systems from contaminated water. A water system with access to any contaminated water source and in turn connected to the local public water system is required to have a device to prevent contaminated water from being siphoned from that contaminated source back into that public system. Although highly unlikely it would ever happen thru an RV black tank flush system, it is remotely possible. And no matter how remote, if it is possible sooner or later it will happen.

When a public water system loses pressure, it pulls a vacuum on those water lines and sucks water back into it from any open source.

[Derby6]

I bought the new part. But it’s just a spare now. The leaking hose bib splitter was my issue.
I bought a new splitter and a quick disconnect for the flush side. Added a gallon counter while I was at it.
Works like a champ.

[JABURKHOLDER]

Originally Posted by Carl n Susan

Rather than a splitter and two hoses running to the RV, I just use the outside shower hose in the convenience center when I need to flush the black tank. I have quick disconnects on the shower hose and the black tank flush connection. That way it takes no time at all to connect, flush, and disconnect, all while sitting right there and not walking away (when bad things tend to happen). ]

I love this idea. Less hoses I need to carry. I also like that I can use hot water for the flush. But I am concerned that I would be using “house” water instead of a separate hose at the park spigot. Do you use a back flow preventer at your black tank flush inlet ?

[Carl n Susan]

Originally Posted by JABURKHOLDER

I love this idea. Less hoses I need to carry. I also like that I can use hot water for the flush. But I am concerned that I would be using “house” water instead of a separate hose at the park spigot. Do you use a back flow preventer at your black tank flush inlet ?

Yes, I use a back flow preventer at the inlet despite the chance of that occurring is less than being hit by lightening or winning the lottery.

[RMcNeal]

Same here. It's inexpensive insurance. I have my water system plumbed such that one hose feeds both the city water inlet and the black tank flush. I have a valve on the black tank flush that I can turn on when I want to flush the tank. I use one like this that is only $5.45 on Amazon...
https://www.amazon.com/EZ-FLO-20199-...s%2C179&sr=8-7

[JAMyers59]

DARYLES, I LOVE YOUR RE-PIPE! I'm flat out stealing that idea in it's entirety.


I had no choice but to put a Backflow Preventer on my rig at the Backwash Connection. When I disconnected my house from that connection after completing my 1st Backwash, water poured out of that connection for over a minute. It was as if I had opened a valve on a pressurized tank. This while the Black Tank Valve was still open and had completely drained. Yes, I will certainly always use a Backflow Preventer AND hoses dedicated to Backwash ONLY.

[bshgto]

Originally Posted by jimcol

Enough people on this forum over the years have reported damage to the black tank from getting distracted when flushing and over filling. Some, not many have reported pranksters turning the shutoff on and causing damage. You don't need to flush the tank every time you dump it unless it's going directly to storage. (I know some people do, what a waste of water) For these reasons I never left the flush hose hooked up except when flushing the tank.

What he said, sooooo simple.