There was a thread that I cannot find now talking about a mystery valve under the bathroom sink. Just checked and our 3511rl has one too. What’s this for? I remember someone saying it had to do with the black tank flush system and they recommended replacing it. What do you replace it with? Sorry for the questions but not an expert on plumbing
Thanks in advance!
That is the anti back flow valve for your black water flush line you should replace it with a brass one before it leaks and floods your rig they like to fall apart.
Bob & Carol
Tacoma WA
2017 352RL 2008 Dodge 3500 DRW crew cab 4x4 6.7L
There have been many postings about these valves leaking. Mine fractured and broke apart and flooded the floor before I could get the black tank flush shut off. Some of us have eliminated that valve by replacing it with a short piece of pipe, and use an external anti siphon valve.
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Bill & Patricia
Riley, our Golden
2007 3075RL (recently sold, currently without)
Consider yourself lucky that the valve is located where it is on your rig. Ours is located between the shower and the pantry, visible barely when looking through the slot where the pocket door slides. I have had no problem with our valve, but we full time and have never operated the flush system without the use of a pressure regulator. Also be aware, if you remove the valve and use a check valve at the hose connection, the water will not drain and that will be another place where you need to winterize, if that is needed. The valve is pictured on this link: http://www.trekwood.com/products/139...placement-Part
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Bob & Becky
2012 3402RL
2012 Chevy 2500HD D/A CC 4WD
Look on amazon has the best price just look up RV back-flow valve they have a couple of
different one if you bypass it the have one you can put on the end of your hose that's what I did works great I just leave on the fitting in the hook up center.
Bob & Carol
Tacoma WA
2017 352RL 2008 Dodge 3500 DRW crew cab 4x4 6.7L
Similar to Rohrmann, mine was in the wall between the shower and the entry closet. And I had to cut a new opening to get to it. The picture shows after I removed the valve and replaced it with some new PEX pipe and fittings. Don't remember the size but you should be able to measure it.
You can see that the picture was taken after I had winterized.
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Bill & Patricia
Riley, our Golden
2007 3075RL (recently sold, currently without)
Its officially called a Vacuum breaker. it vents to the air to prevent a vacuum when the water hose has no pressure. turn water on to flush and the pressurized water pushes the check valve closed so water is directed to the tank for flushing.
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Jason & Wendy
2014 Ford F-350 Lariat 6.7L PSD
2015 Keystone Montana 3711FL
Its officially called a Vacuum breaker. it vents to the air to prevent a vacuum when the water hose has no pressure. turn water on to flush and the pressurized water pushes the check valve closed so water is directed to the tank for flushing.
Thanks. Thought it looked a bit like one of those. I guess if it is a leaky device, it's because it is a cheapo version. Similar to the things used in commercial kitchens and outdoor sprinkler systems and probably inside our toilets to keep untreated water from getting into plumbing if pressure drops or vacuum occurs. Same reason kitchen and bathroom faucets are placed above waterline in sink. Maybe the one in the pix by OP is for the shower since it has a hand wand that could get into the water somehow.
Here is a diagram of a typical black tank flush system. And a cut away view to show how the valve is supposed to work. You can see that if the valve piston does not seat correctly, water can go out the top of the valve.
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Bill & Patricia
Riley, our Golden
2007 3075RL (recently sold, currently without)
Personally I don't want a device that even has the possibility of leaking INSIDE the trailer. That is why I did away with this backflow device. I now use a external check valve at the point of connection.
I agree with fatcatzzz that's y I cut mine off underneath down in the belly at least if it ever leaked it would just run out of the under belly. It wouldn't be so bad but they make
every thing out of plastic buy it it from china when you can get a good brass one maid in
the USA.
Bob & Carol
Tacoma WA
2017 352RL 2008 Dodge 3500 DRW crew cab 4x4 6.7L
Do yourself a favor and get rid of that leak waiting to happen. Take the basement panels off and cut both lines going up into the cabinet. Plumb the 2 cut off lines together with a shark bite type fitting and be done with it forever.
To those of you that think you need a back flow preventer, I just traveled 50 miles with a nearly full black tank plumbed like I described and did not have one drop of black water come out the connection port.
I do not think it is even possible for that to happen unless the tank it WAY over full, pushing the water back out towards the connection port.
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