Power flush! What went wrong?????

[Sdgood1]

Hi all, new to montana AND power flushes. 2014 3150RL Dumped tanks today for first time, all that went well. THEN hooked up power flush and turned water on. I use a clear sewer hose connector to see when its clean. Heard water running and after about 30 seconds didn't see water running out of tank??? turned water off and noticed water running out of the bathroom sink side into the bay.. NOT good, ran into bedroom and the carpet was soaked looked under bathroom sink and water everywhere!!!!! Looking at it there is a white pex line that runs up to what I guess would be a vacuum break, and is for the power flush????????? Anybody else ever run into this??? Guessing maybe the flusher is plugged in tank??? Any ideas or suggestions welcomed

[jeffba]

back flow valve under bathroom sink failed needs replacing. Look for the black plastic valve attached tot he top of 2 white water lines.

[Sdgood1]

Thanx Jeff, That was the problem. Just pulled it apart and blew threw it!!! Which your not supposed to be able to do easily!! Has anybody moved this down into the bay area??? Flooded bay is one thing, flooded bedroom is something else. Luckily I only ran it for about 20 seconds. Still enough to flood a small area.And the bay!!!!! BUT, better at home than on the road.

[mlh]

Back flow valve. Either take it out and throw it away or replace it with a better one or a one way valve.
The back flow valve is a safety valve to prevent contaminating a water system in case the water pressure drops and allows water back in the system. The chances of that probably less than zero.
Lynwood

[waynemoore]

First week I had my new rig I took that thing out and though it away. Used two 90 degree elbows in place of the valve.

[BB_TX]

That cheap valve is a common problem. Some have replaced them with a better quality brass valve. Some of us have eliminated that valve and use an external hose end type anti siphon valve. I bought a hose end type at Home Depot.

If you do choose to replace the valve, it should be at the highest point in the line to work properly.

[Sdgood1]

All good info. I have all the pex tools, so I think doing away with it is probably the way to go. Use a hose end back flow prevention device. Thanx for the info

[DQDick]

I pulled those out of each of our rigs when the rigs were new. Put two ninties on it and now I use an external one on the hose outside of the rig.

[BuilderBob]

Originally Posted by Sdgood1

Hi all, new to montana AND power flushes. 2014 3150RL Dumped tanks today for first time, all that went well. THEN hooked up power flush and turned water on. I use a clear sewer hose connector to see when its clean. Heard water running and after about 30 seconds didn't see water running out of tank??? turned water off and noticed water running out of the bathroom sink side into the bay.. NOT good, ran into bedroom and the carpet was soaked looked under bathroom sink and water everywhere!!!!! Looking at it there is a white pex line that runs up to what I guess would be a vacuum break, and is for the power flush????????? Anybody else ever run into this??? Guessing maybe the flusher is plugged in tank??? Any ideas or suggestions welcomed

Cut the Pex lines off under the floor hook them together and throw that vale in the garbage! you can buy a back flow valve that goes on the end of the water hose. and you will never have that problem agian.

[fatcatzzz]

Replaced mine with a 1/2" street ell and a close nipple. $3 fix.

[ChuckS]

That vacuum breaker under sink is one of the number one causes for folks flooding their fifth wheels when cleaning out black tank...

My 2014 black tank clean out has never been used..and won’t be.. I have an extra coupling with clear fitting and valve and water hose connection and back flush this way... keeps black and gray tanks cleaned out quite nicely..

The factory clean out connection only rinses the black tank..

Some will say the add on coupling won’t work.. depends on how the holding tanks drain line is routed..

Mine are all fairly level so washout is easy and effective

[Sdgood1]

Thanx all for input. After pressure washing the bedroom, I am going to loop the power flush line in the bay and get it Out of the inside.

[DebNJim B]

Originally Posted by BB_TX

That cheap valve is a common problem. Some have replaced them with a better quality brass valve. Some of us have eliminated that valve and use an external hose end type anti siphon valve. I bought a hose end type at Home Depot.

If you do choose to replace the valve, it should be at the highest point in the line to work properly.

Great images to show how this is suppose to work. But as I look at this it would seem that valve would allow tank gases to enter back into the bathroom once that valve is closed.

[daveinaz]

Well, I had a similar problem this weekend!!

I hooked up the hose to the sewer flush connection at the convenience center. Turned on the water. Waited for clear water to flow from the hose. No water from hose, but water started pouring from underneath the RV to the right of the convenience center! It was even coming out of the furnace cover opening!

I've read that that valve is located in the wall between the pantry and the shower. Is there some sort of pressure overflow valve that would make it leak where it did?

Ugh

[DebNJim B]

Originally Posted by daveinaz

Well, I had a similar problem this weekend!!

I hooked up the hose to the sewer flush connection at the convenience center. Turned on the water. Waited for clear water to flow from the hose. No water from hose, but water started pouring from underneath the RV to the right of the convenience center! It was even coming out of the furnace cover opening!

I've read that that valve is located in the wall between the pantry and the shower. Is there some sort of pressure overflow valve that would make it leak where it did?

Ugh

That valve on my 3731FL is located directly behind the conveneince center right after the flush connection.

[BB_TX]

Originally Posted by DebNJim B

Great images to show how this is suppose to work. But as I look at this it would seem that valve would allow tank gases to enter back into the bathroom once that valve is closed.

It does seem possible. But can’t remember anyone ever saying theirs did.

I suspect the small holes in the spray head vs the large roof black tank vent pipe allows all the odor to go out the roof vent.

[MidMOTraveler]

Originally Posted by DebNJim B

That valve on my 3731FL is located directly behind the conveneince center right after the flush connection.

Wow! I was just about to ask if any 3731FL owners knew where the valve was located.
Love this forum!

[DebNJim B]

Just found it by chance while replacing the outside shower faucet.

[Sdgood1]

The valve does 2 things. It is a vacuum break and a back flow prevention device. hook up at convenience center turn water on, pressure closes the vacuum break and pushes the spring open to send water to flush head. pressure off, closes spring and allows vacuum break to reopen. REALLY stupid IMHO. I also noticed there is a built in back flow prevention right at the hose hookup!!
Took mine out from under the bathroom sink (after flooding bedroom) and left the one in the convenience center.

[beeje]

These valves are nothing more that a government mandated device that can and will destroy your RV. Get rid of it. Cut the lines in the basement and plumb them together.