Back Flow Preventer On Blank Tank Flush?

[LongIslandCamper]

We have the factory installed black tank flush kits in our TT's. Would I need a backflow preventer on the line? Some people have said their flush systems already had a built in preventer. Do mine?

[lx22f/c]

It already has one. Location will vary from each model. O my 07 3314 bhds it was located under a vanity behind a drawer. It seemed strange that jayco would put the flush line on the right side of the camper since all valves located on the left.
When mine developed a leak in the black tank flush fitting i replaced it with a tornado flush and relocated it near my black tank valve. The tornado came with a back flow preventer.

[David472]

I have the same TT as you. The back flow preventer is located in the second from bottom shelf of the bedroom corner wardrobe. This is right where the line comes in from the outside connection. It is a square-looking black cube about 1.5 inches square.

[J.Lockhart]

There is one... but if it's like mine... you still get a back flow of water that is in the RV plumbing line. To solve that, I installed a stainless steel check valve / one way valve purchased @ RV WATERFILTER STORE

http://www.rvwaterfilterstore.com/UsefulGadgets.htm

Now, I get no water coming back out of the flush line.

[troutslayer]

There is one there and it's one of those things that will need to be replaced at some point. It's good that others have helped you with the location. There will always be a certain amount of water that seems to flush back out through the hose but, not to worry, it's the normal water pressure built up in the hose that has not been allowed past the check valve. I've also heard that it's always good to NOT run the flush with the dump valve closed (how's that for a positive/negative statement?).