Plumbing question

[rickbecker]

I had occasion to be under the back sink of my 3150RL and found a plastic line that I do not understand. Blue and red water supply lines, sink drain line no problem. But, there is also a white line that has some type of valve T'd in. I do have a washer/dryer in the nose of the rig and the white line continues in that direction after the T.

Can someone 'splain to me the white line?? Thanks!

[BB_TX]

That is the black tank flush antisiphon/back flow preventer valve. Keep an eye on it. They are prone to failure and may flood your interior if not caught in time.

[DQDick]

The first mod I did was to take it out and use an external one. Thus we've never had it leak. I put the external backflow preventer on the end of a short garden hose saver and then quick disconnects on each end (all my hoses and the connections in the convenience center use the same quick disconnects). Here's a picture: http://s1221.photobucket.com/user/DQ...ml?sort=3&o=15
I got my disconnect at a hardware store, but if you do this, this is what you need: http://www.amazon.com/LASCO-05-1763-...flow+preventer

[oldelmer1]

Guys, I believe in the 3150RL the anti siphon/back flow preventer is located behind the shower wall. At least that is where mine is.

Rick, mine has what you explain, but I have 2 T's in the hot/cold water supply lines going to the washer.

Are you saying you have a 3rd line with this T on it.???

Got any pictures??

[rohrmann]

If this single line with a valve on it is under the rig, its probably the fresh water tank drain line. When winterizing, you will want to open this valve. I've also drained the tank if we have had full hookups for a long time and just want fresher water in the tank.

[rickbecker]

here is a link to 3 pictures:

https://rbeckerpics.shutterfly.com/#%3aemid%3dsite_sitecreated%26cid%3dSHARE3SXXXX

After opening up under the sink a little more, it looks like BB_Tx is correct - this is the black tank flush antisiphon/back flow preventer valve. The line does NOT go on to the washer, just up under the sink and then back to basement.

[BB_TX]

Yeah, that little black valve is for the black tank flush. Many of us have eliminated that valve like Dick noted above. I eliminated mine after flooding my carpet. Dick was smarter and eliminate his before it leaked.

[oldelmer1]

Rick, they must have changed the location, mine was behind the shower wall. A stink bug climbed into mine and stopped the seal from happening when the water cam on, leaked all over the basement.

What year is your 3150RL, mine is 2010.

[mlh]

Mine started leaking and I replaced it with a one way in line valve I got at the hardware for way less than half the $80 price of the one that came in the camper.
Lynwood

[rickbecker]

Our Montana is a 2013 3150RL - thanks for all the replies and now that I know what it is and what it can cause I believe it will be gone shortly!

[MIMF]

Rick, our unit has that very same leaking valve under our bath room vanity! Something else that is going to get replaced very soon. I tried the tank sprayer earlier this summer one time to check this cheap piece of crap and, sure enough......leaking all over under the vanity! Just glad I use a Flush King at the termination connection.

[rafael33155]

do you actually need that or can it be eliminated completely do i remove the valve and put an loop from one white hose to the other?

[jimcol]

You are correct. Get a plastic or brass elbow, female threads on both ends. 5 minute job. Then as others have suggested put a back flow preventer on your hose before connecting it to the outside flush valve hose bib. Jim

[Rondo]

Only problem with putting that backflow preventer at the point of entry of the black tank flush connection is that every time you turn off the water to it, it will leak water or back flow the water from the vents on the valve inside your convenient center. Believe me, I tried it and had water coming out of the convenient center hole every time I'd turn the water off the to the back flush. They had that type of valve on all of the faucets at the Mid Atlantic (if they hadn't been stolen or removed by other campers prior)and everyone of us got soaked until we learned to hold our hands over the coupling when shutting off the water. It would spray a stream in four directions about 4-5 foot when you turned the faucet off!

[cumminalong]

Can you not remove the backflush hoses all together? an plug them off,or reroute them to the convenient center? John R.

[jcurtis934]

The high loop is to reduce back flow out of the black tank and into the water supply. That's why we have left the lines inside and joined them together and used a backflow outside the rv. John

[fernsco]

I just used my black tank flush and sure enough, water all over the place. Question. Does the leak only occur when using the black water tank flush? If I don't use black tank flush until I have a chance to fix it is there any harm? Once I disconnected it and hooked back up to normal water supply and flushed the toilet a few times I did not notice any further leakage. thanks!

[BB_TX]

It will only leak during a flush. No other water is connected to it. So if you do not connect to it you will be fine until you can fix it.

[fernsco]

Thanks Bill. Appreciate the reply so I can go back to relaxing rather than worrying.

[Phil P]

Hi

Keystone never installed mine just the lines with a coupling between them.



Phil P