Black water flush line?

[artandsherry2]

We have a 2005 3400RL Montana that is pre-owned. The flush line does not work at all, even tried using an air hose to blow it out with no luck. I contacted Montana, they pulled up the engineering prints and show no flush line what so ever, even with a factory installed flush line. Is there a shut off valve hidden out somewhere? Since the tank is under the basement floor there is no way to trace or locate the flush line. Could the tank be polluted to the point the flush nozzle is covered up from the inside? Any help will be much appreciated and if the previous owner misused the tank how can we get the build up cleaned out?

[JandC]

It could have been disabled over time. It is hard to tell why it isn't working. If it was me I would purchase a Flush King to fasten onto your sewer boom. With a Flush King you can backwash your black tank and it accomplishes the same thing. Even on my 2014 unit it is the only method I use. I can also close off my black tank and flush out either of my gray tanks if I need to. Hope this helps or at least gives you another direction to go.

[dieselguy]

Like said ... you new purchase has one of two usual scenerios with the tank flush. Either the previous owners experienced the anti siphon valve leaking and just capped off the line at that point, or the nozzle inside the tank is plugged up. It's alot of work to drop part of the belly pan and get to the nozzle let alone clear it. There are better quality tank sprayers out there ... having one installed using the existing line would be the better way to go if you absolutely want a tank flush. Or you can use JanC's advice. If we are at a campground dump station that has no hose to attach to our black tank flush, I just fill a 3 gallon bucket 2-3 times with water and dump directly in the stool with the foot valve open.

[artandsherry2]

Thanks to all, I think I'll buy one of the Flush King setups and quit trying to figure out a line that I may never get to work. Who knows what the previous owner did or did not due. Thanks again and when I get home I going to fill the tank and add some Roebic to the water and just let it sit for a few weeks and see what comes out.

[jcurtis934]

If you see four pex lines under the bathroom sink, that is where you will find the anti-siphon valve. It could be stuck to the point of allowing no water to flow...but taking it out to examine it is easy. Also likely is the former owner saw no value in a black tank flush and never used it so it could plug over time. The flush port is at the very front of the tank and easy to get to when the bottom is removed from the front of the frame. Just another screw on pex fitting for the flush line, so it is easy to unscrew and see if water will flow out of the line. John

[bncinwv]

I believe on a 3400 that the anti-siphon valve is located between the shower and the small kitchen pantry where the pocket door retracts. There should be some kind of access door in the rear of the pantry that will allow exploration of this area.
Bingo

[CWSWine]

quote:Originally posted by artandsherry2

Thanks to all, I think I'll buy one of the Flush King setups and quit trying to figure out a line that I may never get to work. Who knows what the previous owner did or did not due. Thanks again and when I get home I going to fill the tank and add some Roebic to the water and just let it sit for a few weeks and see what comes out.

Before you buy the flush king you might want to watch this video. This guy put a lot effort into testing flush kits.

https://www.youtube.com/watch?v=dfTd0Slt_cU

[DQDick]

I agree, few of us have a straight shot into our tank.