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  1. #1
    Left The Driveway
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    backflow preventer on the black tank flush

    First of all does the Nautilus P1 have a backflow preventer on the back tank flush? And would it be a bad idea to use a Y on my fresh water hose to go to both my city water and my black tank flush assuming that there is a backflow preventer or adding one to the line if there isn't? I want to avoid running a hose every time I want to flush the black tank during the winter.

  2. #2
    Seasoned Camper joesmainship's Avatar
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    No, the Nautilus does not have a backflow preventer. I regularly use the coiled hose to feed water to the blackwater flushing system. I do try and flush the hose for several minutes afterwards. It needs a backflow preventer because when I undo the hose, water flows back out the blackwater flush connector.
    The Capt and the Admiral
    Joe & Marilyn
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  3. #3
    Rolling Along RVRunners's Avatar
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    I always use a separate hose for flushing the black tank.
    The Adams - 2017 Reflection 367BHS, 2019 F-350 6.7L PSD 4x4 CC DRW, B&W hitch on Ford pucks, Air Lift Loadlifter 5000 Ultimate Plus air bags, "Rupert" the Weimaraner.

  4. #4
    Site Sponsor JCR GD's Avatar
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    There is a check valve/ vacuum break in the line between the hose connection and the tank but it is above the hose connection (by design) so there is a bit of back flow, but nothing from the actual tank.
    Jim (& Sharon)
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  5. #5
    Site Sponsor Cate&Rob's Avatar
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    The Nautilus panel does not have a backflow preventer, but the black tank flush line has a vacuum break located higher than the toilet bowl rim (by spec). This is why water flows back out the flush connection when you disconnect. The line empties in both directions fron the vacuum break, to the tank and to the flush connection.

    Some folks seem to think that if they put the Y connector joining the drinking water line and black tank flush line all the way back at the post, they are somehow safer. It really doesn't matter how close the Y is to the trailer. The best safety measure is to never leave a hose attached to the black tank flush connection unless you are actively flushing the tank and know that there is pressure in the flushing hose.

    It would take an unusual combination of several failures to get the black tank contents to flow out the flush line and back in the potable water intake . . . but if this were to happen, the length of the hoses wouldn't matter much.

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  6. #6
    Big Traveler CWSWine's Avatar
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    I use to hook up the out side shower hose to the black tank flush and use hot water to final flush the black tank. I did have check value between the hose and the connection just to add a additional failure point and piece of mind.

    Last summer a 5er pulled in next to use the couple seemed to be in a hurry to hook up then jumped in there truck and took off. Few minutes after they left the contents of the black tank was coming out the roof vent because they hooked up the water up to the black flush by mistake. The bad part was it splashing all over the water shutoff value. We had to call the camp ground owners to come shut off the water at the main value.

  7. #7
    Big Traveler
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    Quote Originally Posted by CWSWine View Post
    I use to hook up the out side shower hose to the black tank flush and use hot water to final flush the black tank. I did have check value between the hose and the connection just to add a additional failure point and piece of mind.

    Last summer a 5er pulled in next to use the couple seemed to be in a hurry to hook up then jumped in there truck and took off. Few minutes after they left the contents of the black tank was coming out the roof vent because they hooked up the water up to the black flush by mistake. The bad part was it splashing all over the water shutoff value. We had to call the camp ground owners to come shut off the water at the main value.
    Oh man, that poor couple and especially the guy that dealt with the poo laced rain to turn off the tap

  8. #8
    Site Team Second Chance's Avatar
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    I use a "Y" when there are not two water standpipes (as seen at some Escapees parks) at the site. I have a back-flow preventer permanently attached on the side of the "Y" used for the black tank flush. I do not leave the dedicated black tank flush hose connected when not in use - only while flushing. We have not had a problem in 28 months of full-timing. I use a variation of the Geo method to periodically clean the black tank on a travel day.

    Rob
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    (Previously in a Reflection 337RLS)
    Full time since 08/2015

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