Hello, We traded our TT for a 2010 Keystone Montana 3455SA last week. It has a black tank flush hook up in the convienance center. When we hook a hose up to rinse the black tank out, fresh water leaks out into the floor of one of the cabinets under the desk area beside the kitchen. Has anyone experienced this? We're taking it to the dealer for service. The dealer gave us a 30 day plumbing/appliance/electrical warranty. I'm guessing a leak in the feed line into the tank?That's about the only thing we found wrong through our first weekend camping and trying everything out. We love everything about the 5er, especially all the room! :)

Backflow preventer is probably the cause of leak

Not all that uncommon. Black tank flush systems have an anti-siphon valve - back flow preventer (some times called a vacuum breaker). It is usually located inside a cabinet inside. Mine is under the bathroom sink.It can leak if the water pressure is high or it can leak if it fails or it can leak just if it wants to leak..Mine doesn't really leak, but sometimes it "weeps" a little. I just put a towel or dirty shirt from the laundry under it and all is good.This is an example...it's not mine. (found the image on Google)Well now, there you go Biscuit..you beat me to it again..Is that picture that I pirated YOURS???

Many Montana models, and probably other makes/models, have cheap back-flow preventers plumbed into the black tank flush systems. If your dealer replaces it with the same kind it will probably leak again some day.

Mine did the same thing, leaked all over the floor. Common problem with black tank flush systems. But my antisiphon/vacuum breaker valve was inside a wall behind the shower. Fortunately I could get to it by cutting a hole in the back wall of a cabinet on the opposite side of that shower wall.Join the Montana Owners Club (MOC) forum for all questions about your Montana. Lots of expertise, experience, and friendly folks there.

I am experiencing the same thing with my Outback. It started last summer. I quit using it after flooding the camper twice. This last week-end I had the wife turn the water on at the spigot and I watched inside. Mine is under the sink.Turned out there is NOTHING wrong with with the anti-siphon valve.The problem is right where the garden hose attaches to the outside. Water came gushing out all around there. As the outside is sealed completely with calking, the water had no where else to go but under the cabinet inside the camper. I was going to disconnect it, but we were still camping, and if I remove the outside fitting (where the garden hose attaches), I want to make sure I have access for a replacement and a calking available. As we were camping when we ran the experiment, I decided to wait till we get home.If you can run a similar test, I bet you will find the water hose connection is also spewing water inside the camper. Nothing is wrong with the anit-siphon valve. I was ready to take mine off too and just replace it. That would have been a waste of time and money. Check the connection where the garden hose attaches (inside the camper).FYI, Montana and Outback are both Keystone campers. I bet they use the same part for the black-tank flusher.

Black tank flush system leaking | Good Sam Community

kennethwooster
Explorer
May 06, 2015
Did not blow mine out one fall, and it froze. Now I always blow a little air through the system.
titleman
Explorer
May 05, 2015
Had the same thing happen in my Artic Fox a couple of years ago. Mine is located in the wall behind the shower. There was an access panel in the bedroom so that helped a lot. Got my manual out and read it. It cautioned that when you turn on the water to make sure it was wide open and when you are finished turn it off completely.

After cleaning up a bunch of water and drying the carpet in the bedroom, I tried again, following the instructions, and have been using it regularly ever since with no problems. Apparently it takes a quick full water pressure to open the thing.
RECVEH2005
Explorer
May 05, 2015
I had a similar problem when our fiver was new; it turned out that the hose was not tightened at the tank entrance fixture. The problem was corrected via warranty. On our previous fiver a leaking problem was the hose not being tightened at the vacuum breaker.

Mike
DutchmenSport
Explorer
May 05, 2015
Tennessee_Nomad wrote:
DutchmenSport wrote:
Tennessee_Nomad, just wondering if you get your flusher to stop leaking, and what you did to fix it.

Took mine back to the dealer. They replaced a vaccum breaker and a 1/2" saniprene seal. Seems to have fixed the problem.

Great! Glad it worked out OK for you! Thanks for the update!
lpxguy
Explorer
May 04, 2015
I had the same leak problem last fall on last trip out....valve broke, water streaming out of underbelly. Once I found my valve (behind shower water valves) I replaced it with one of these

made of bronze. Turns out those plastic ones have a high failure rate.
Tennessee_Nomad
Explorer
May 04, 2015
DutchmenSport wrote:
Tennessee_Nomad, just wondering if you get your flusher to stop leaking, and what you did to fix it.

Took mine back to the dealer. They replaced a vaccum breaker and a 1/2" saniprene seal. Seems to have fixed the problem.
Dave_H_M
Explorer II
May 04, 2015
:S I can't believe i also learned the hard way that that system has to be winterized or you just may end up with a cracked anti siphon valve.
DutchmenSport
Explorer
May 04, 2015
Tennessee_Nomad, just wondering if you get your flusher to stop leaking, and what you did to fix it.

This week-end (while camping) (actually this morning before breaking camp), I finally replaced the part where the garden hose hooks up to. Because it was located under the bathroom sink, in the cabinet, it was an easy replacement. It took longer to get the old putty off the outside of the trailer than anything. But replaced the part, tried it, and everything is still dry! Yea! (and it was not the anti-syphon device either!)

After replacing with the new part, I looked at the old one very carefully to see if I could figure out why it leaked so bad. I didn't see any noticeable cracks or anything, but then "it" caught my eye!.... DUH! ... The rubber washer was gone! You know, the little rubber washer inside the female threaded end when 2 garden hoses are connected? Well, the flusher hook up end was missing the washer. I suppose it fell out or something. This would explain 100% why water was spewing inside the camper, flooding the floor! Duh!

So, it's possible I didn't need to swap the part out, all I needed to do was get an old garden hose and pull the rubber washer out and try it. But, the new one has the rubber washer, no leaks, it only took about 30 minutes for the job and everything is working good again. So I suppose, it was a good day after all!

So, I was thinking of you this morning when doing the fix and wonder if you got yours taken care of too? What the problem finally was, and how you fixed it?
2-MTnesters
Explorer
Apr 22, 2015
I had the same problem with my 2010 Montana. Found that the back flow preventer had cracked over winter. When winterizing, previous owner aparently didn't pump any antifreeze through it. I was able to buy a new one from amazon exactly like the ORIGINAL one. It is located in the wall that separates the bathroom from the kitchen. I was able to loosen the shower faucet, pull it out from the wall and reach into the wall and snake the tubing and backflow preventer through the opening. You can get a much better brand than the original but I believe if properly winterized this will not happen again. You can PM me with any questions you may have. Tim
Lantley
Nomad
Apr 21, 2015
Was the tank flusher winterized?