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poisonivy's avatar
poisonivy
Explorer
May 08, 2014

Black tank flush 2009 Big Country

Hooked hose up to flush black tank, water showed up in floor of fifth wheel. What kind of problem do I have and how hard is it to fix. Any help would be appreciated. Thanks
  • Did you have the black tank drain valve open while you were flushing the tank?
    That is a requirement. Otherwise the tank will fill quickly and overflow...
  • You might have had one of the flush lines come loose, the main line from the outside splits into at least 4 smaller lines that are attached to the black tank to create the flush action. I had one come off and flood my floor on a 2006 cardinal. Had to drop the belly pan and the black tank to fix it.
  • There is an anti siphon valve that might be leaking.
    Mine was under the bathroom sink behind a removable panel.
    If the water pressure is too high, they can leak around the fitting.
    Good luck.

    Bill
  • Might be the vacuum break valve. The flush water line has a loop in it that is positioned higher than the outside water flush connection. The vacuum break valve is located at the top of this loop. Mine is located under the bathroom sink.

    Also called anti-siphon valve.
  • 12thgenusa wrote:
    Might be the vacuum break valve. The flush water line has a loop in it that is positioned higher than the outside water flush connection. The vacuum break valve is located at the top of this loop. Mine is located under the bathroom sink.

    Also called anti-siphon valve.


    This would be my bet.
  • Yep, most likely that antisiphon/vacuum breaker valve. Failure of those valves is a common problem. If you are lucky it will be under the sink in the bathroom vanity cabinet. If not so lucky it will be inside a wall, likely behind the shower.

    Look for something like this. Or it could be clear plastic.

    Been there.
  • This is what mine looks like. Was behind a panel in the computer desk. Leaked the first time I used it. I bypassed it and installed a shutoff valve behind the inlet fitting. Chris

  • Is it leaking inside the living area or the basement floor? I had one of mine leak into the basement and started pouring water out of the underbelly. Come to find out my garden hose had some screwed up threads on it and it didn't make a good seal, so the water was shooting past the connection and into the basement. Replaced garden hose with new and never had another problem.