Check Valve - Montana Owners Club

Tom S. · 08-13-2009, 06:52 AM

When I tried to use the black tank rinse, it doesn't work. Since I can't hear or see any water going through, I am guessing it's the check valve (or back-flow preventer). Can anyone tell me how to get to it on our 06 3500RL, and where I should look for a replacement if I can't fix this one?

Thanks!!! (and yes, I did search and search, but I get some strange results when I search on this site!)

Exnavydiver · 08-13-2009, 07:23 AM

Tom, I couldn't find floor plan for 3500, if your shower is on the drivers side and there is a large pantry cabinet behind it then you can see the backflow preventer by looking along side the pocket door up about shoulder level behind the shower. Otherwise I would look underneath the bathroom sink. Most RV centers have the replacement and it is usually cheap ( both in construction and cost). Don't forget to shut off and vent the water pressure... Dave P.S. I forgot to mention that if it is behind the shower you will have to cut a hole in the wall of the pantry cabinet. I would use a utility with a new blade, less mess and no accidents... Dave

DL N K · 08-13-2009, 07:45 AM

We have an '05 3500RL and the shower is on the door side of the RV. While we haven't had a problem with the valve, I have laid eyes on it. On ours it's between the rear wall of the closet/pantry on the right just as you walk in the entry door and the shower wall. When I open the upper closet/pantry door, I see a plastic panel on the back wall of the closet/pantry that's about 8" to 12" inches square. When you remove it you'll be looking at the sliding door that closes off the bedroom. Close the door and you'll be looking at the back side of the shower wall where the facuet is. Now, on our's the backflow valve is quite a bit lower than the opening but can be seen with a mirror. What I plan to do if I ever have to access ours is to cut another opening in the back of the closet/pantry wall right around where the valve is located. The opening may even be so low that it will be in the lower closet. If I can't find anything else to close the hole when finished, I'll head to Lowes and pick up a piece of plexiglass a little bigger than the hole, paint it black and put screws in each corner to hold it in place. A scrap piece of thin plywood would also work. I know some may say it's wrong to do, but if ours ever fails, I'll probably remove it and splice the 2 lines together with a union. I feel that as long as a person is carefull, backflow issues can be avoided, i.e. as soon as finished flushing, disconnect the hose from connection to prevent any vacuum. The only time a hose is hooked to ours is when actually backflushing. Hope this helps.

KTManiac · 08-13-2009, 09:56 AM

I have the same problem, but when I had the basement wall off for something else, I disconnected the water line between the back-flow check valve and the black tank. I hooked up a hose to the easy flush fitting in the convenience center, and a length of hose from where I disconnected the PEX to outside of the basement. Then I turned on the water and it flowed OK through the check valve. So that means, it is plugged downstream from the check valve.

After a phone call to the easy flush guys, and finding out that there are no moving parts in the tank sprayer head, I have concluded that the sprayer head is clogged up with dried Poo. I have tried filling the tank completely full and letting it soak, opening the black valve and leaving the water turned on to the easy flush for hours on end.

There is still no joy in Mudville! (pun intended) I think that I will try to make a miniature Roto-Rooter out of wire and try to clear it up that way. If that doesn't work. that leaves me with taking down the belly and removing it from the tank to clean it out. I think I will leave that one for the dealer to do, as it is still under warranty.

sreigle · 08-13-2009, 04:20 PM

On our 2007 3400 it is behind a panel in that pantry in the kitchen on the back side of the shower. However, on ours the hole is not properly lined up and the valve is actually below the hole. So a new hole or enlarging the original hole would be required to get to it.

On our 2003 3295RK it was under the bathroom sink in the storage area of the vanity.

firetrucker · 08-13-2009, 06:10 PM

The check valve is really simple, so, as KT said, it's probably the spray head that's clogged. I've been lucky enough with mine that soaking and running the flush, like KT did, opened it up. I'm anxious to hear if the rooter method works, cause it's easy to get to the supply line.

Bob

JimF · 08-14-2009, 05:04 AM

We had the same problem with a different cause. I leave a hose hooked to the black flush but had left it disconnected from the faucet. Some leaf cutter ants use the hose as a nest and filled it with little round discs of leaves, made a very effective plug.

Mrs. CountryGuy · 08-14-2009, 05:44 AM

We managed to unplug one time with the long soaking method, with a bit of All laundry detergent and Calgon Laundry additive in the tank during the soaking process.

Since then, we are again having trouble, thought we had it spraying, now plugged again.

CountryGuy will not be pulling the tank. We have just about decided to live without it, we did on all prior units, we can again. SIGHHH

Exnavydiver · 08-14-2009, 05:59 AM

You really don't have to pull tank. Just drain tank completely and drop belly pan on door side by steps as this is close to where most black tank flush units are located. Use a stubby screwdriver and after you disconnect the flush hose and elbow you can unscrew the sealing gasket and bracket from the side of the tank and just draw the flush head out. It will probably be nasty so toss it into a buck full of soapy water with clorox to start soaking it. I watched this procedure done on our rig in Jackson, TN when they serviced our flusher. It took the tech about 15 minutes to get the nozzle out, check it, and re-install it.... Dave

Art-n-Marge · 08-14-2009, 08:10 AM

JimF... I leave my hose connected on BOTH ends because of that possibility. I added a ball type shutoff to control water flow as needed. This prevents any outside critter intrusions.

JimF · 08-14-2009, 10:07 AM

No kidding Art, we learn from a mistake, right after we make it.

Tom S. · 08-18-2009, 02:36 AM

Thanks for all the replies. I pulled the basement panel back hoping I would be able to access the valve, but no luck. Next step will be to do what Dave said, pull the belly pan. Working under the trailer is mentally hard for me. Something to do with a S-10 pick-up that ended up on me while I was working under it. Luckily my wife was kind enough to drive it off me and I obviously survived, but it left a lasting impression (pun intended). I'd also like to install the new sensors someone mentioned in another thread, so I think when I do work up the courage to go under there, I'll kill that bird too.

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