View Full Version : Fresh water Flush valve located in my black-tank system???

11-16-2011, 03:28 PM
I have a 2010 Montana/Hickory Edition...4 slide/34' 5th wheel trailer and have a problem when I use the fresh water flush when emptying the Black tank...I see water leaking out of the bottom of my basement area....I need to check this "check-valve"....WHERE IS THIS check-valve LOCATED????
Thanks for information on the location...I am sure I can fix this problem-if I just know where to look for this "check-valve".

11-16-2011, 04:58 PM
Most check valves are under the bathroom sink cabinet up high. Probably water is probably leaking from the check valve and following the pipe back down into the cargo area. Hope this helps. Happy Campin................Ron

11-17-2011, 10:50 AM
Go to the Montana owners forum (montanaowners.com)

11-17-2011, 05:02 PM
I have a 327res cougar and the same thing happened with mine and it was just a loose fitting, tightened it up and not problem.

11-17-2011, 05:53 PM
Usually there is an "antisiphon" valve located on the actual fitting at the tank. On mine, there is a garden hose connector,antisiphon valve, flange with 3 screws and then the fitting. This assembly attaches to the side of the black tank. There is a clear plastic hose which attaches to this device, the other end of the hose is located in the trailer sidewall. When in use, the campground water supply is attached to the trailer sidewall, water flows through the clear plastic hose, and into the black waste tank. I think what you're saying is happening is that the hose fitting on the assembly at the black tank is leaking and you see water dripping out of the bottom of the trailer. That, I think is what MILBY said he tightened to stop his leak. It is on the side of the black tank.

11-18-2011, 01:38 PM
I have a 2011 Cougar HC 291RLS, had the same issue. Antisiphon under the bathroom sink had a small piece of debris stuck in it and wouldn't let it seal, removed it and all has been fine. Has sealed every time since .
Enjoy your travels.

11-18-2011, 01:45 PM
Mine was under the sink at the check valve one of the fittings on the pex tubeing was loose. Also I posted this before and so have many others do not forget to winterize that black tank line also, I ruined that check valve on my last trailer by forgeting.

09-09-2012, 06:04 PM
In most Montana models the check valve is up high in the wall. Mine is behind the shower, in the wall, about 5-feet above the floor. In the pantry, there is an access panel that you can remove to gain access to the valve.

The clear plastic ones crack very easily if you don't do a really good winterizing job. I've had to replace two in the last 5 years - and I DO blow antifreeze through the flushout line.