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brianseay1's avatar
brianseay1
Explorer
Mar 13, 2023

Black tank clean out

Can someone point me in the right direction to find the plumbing layout fir the black tank washout lines in a 2007 Coachmen Cross Country 389DS ? I’ve been googling it and can’t find anything for my specific coach. I went to wash my tank out today and started getting water running across my floor in the bathroom area. Had no water leaks at all over the weekend until I went to wash out the tank. I can’t see my tanks and I haven’t been able to climb under the coach to try and see what I can. Camped all weekend with no issues, so I’m figuring it’s gotta be in the wash out line that’s leaking. Any help is greatly appreciated.
Class A
  • Rick_Jay's avatar
    Rick_Jay
    Explorer II
    Mar 13, 2023
    Look for a vacuum breaker under your sink which connects to the black tank flush system. Here's a link to a kit which has a brass vacuum break.

    Black Tank Flush Kit with Vacuum Breaker

    The brass unit is the vacuum break. This is similar to the one in our rig, but ours is under the kitchen sink. The disk part of the breaker should point upward with the two pipes coming up from the floor.

    It is only connected to the black tank flush plumbing, so if you're not flushing your tank, it won't show evidence of a leak.

    The vacuum break line has to be higher than the rest of the plumbing for the flush system to help prevent siphoning, along with the vacuum breaker, which is why they're mounted inside and usually under a sink cabinet.

    Hope this helps.

    ~Rick
  • wildtoad's avatar
    wildtoad
    Explorer II
    Mar 13, 2023
    Check in your bathroom cabinet(s) under the sink. You may find the piping to the black tank. It will most likely have a small plastic back flow preventer which have been known to fail.

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