Black Tank Flush Problem

[RonD]

This can only happen when your 2500 miles from home, I was flushing the Black tank, and draining the others, and when I was done there is water pouring out the bottom in the area of the main drain ABS plastic pipe. So we move on to the next overnight stop, I wanted to find what was leaking, so I ran the shower for 20 minutes, no leak, drained the gray tank, no leak, added water to the black tank, maybe 10 gal, no leak, so it looks to me that the flush line failed someplace. I think I know what I did, we were in a few parks that had very high water pressure, like 100 lbs or more, I run a regulator on the supply hose, but just ran the flush directly, so it looks like it blew something. Ours is a 3075RL, I understand the 3100RL have a back up valve behind the shower wall, ours should be the same as a 2955, I haven't taken anything apart and won't when were gone, but my main concern is sewage backing out the broken flush line when the tank gets full to some point, and where on the tank is the flush line attached, top, front?, I can access the better part of the tank from the top after removing the wall down under, any ideas?, thanks Ron

[jimcol]

Look under the lavratory sink for the back flow valve but I doubt that is your problem. If it were leaking there you would have water all over the floor and in the bottom of the vanity. According to the installation instructions "Drill 1" hole on side or end of wasteholding tank, no more than 2" from the top of the tank near center." Looking at the diagram it appears there may be a couple of elbows past the check valve where the piping could have come loose. If you can get by without filling your black tank too full sounds like you might be OK until you get home. Jim

[DQDick]

It also could be as simple as the connection on the back of the convienence center where it hooks into the hose connection. I'd pull that wall first and look at that rat's nest. That would be the easiest fix if it's in there.

[jpkelpe]

in our 3150 Keystone showed us the backflow prevention valve is behind the shower--you remove 4 screws on the wall where the faucet is and the pipes, etc are behind that wall. They said the valve is rated at 125 psi--it is a clear valve. We had a "flood" too here at the Rally

[kdeiss]

We had a leak about two weeks ago under the vanity sink in our 2955 dripping into the storage area,
The fitting on the back flow was just loose

[tim43]

My back pressure relief valve broke when I first got the rig and flooded the living room area. Got it replaced under warranty and purchased a spare valve. Haven't used the system since. Now I just dump, refill, and dump again.

[oldelmer1]

The flusher is located on the very end of the tank, oposite the drain valve. The tank is tapered, thinner on the flush side, thicker on the drain side. On my 3150RL, if I was to drop the passenger side front underbelly, I would see the PEX water line going to the sprayer. My water line comes to the sprayer from the middle, between the 2 tanks(black & shower).

[RonD]

Great, thanks for the info, I pulled out the plastic wall to look at the back side of the convienence center, everything is in tact, I followed the water PEX pipe, it goes up the wall with the shower pipes, so it appears that is where the valve is, why there?, that is a bad place, but anyway, it can't be the cause or water would have been all over the floor, I know because the shower valve freeze cracked 2 years ago and we had a leak. So now it sounds like the sprayer is on the end of the tank, that should be the front end, and that is an easy part of the under side cover to remove, my guess it blew off the end, I will find out soon, I may try the fix since were in one place for two weeks and we have company to help, thanks again, Ron

[Exnavydiver]

Crawl under the rig on the curb side about even with the steps and drop the belly panel. I believe that the PEX to tank fitting failed and when ours did that they just pulled the belly panel, reached up and unscrewed the failed fitting and installed a PEX elbow in its place. That fixed the leak and we have never had a problem since.