No fuss flush mystery

[nodine]

We have owned our 2006 Diplomat 40PDQ for ten and half years and the only problem we have had with the "No Fuss Flush" was the spray nozzle became stopped up. That was an easy fix but now we have a problem that stumps me. This happened all at once about four days ago when getting ready to break camp. We turned on the water to the black tank flush and heard the usual sound of water running for about two seconds and it stopped. My first thought was the nozzle must be plugged and went around to the other side of the coach and removed the PEX line expecting water to rush out. No water came out which immediately turned my attention to the anti-siphon AAV/check valve apparatus under the hallway sink. I removed both and had the wife hold a container under the supply line while I went back outside to turn the water on. Water flowed so we went to Lowe's and purchased a short flexible line and temporally bypassed both the check valve and the AAV. Water still did not reach the flush nozzle input.

So my question is has anyone else had this problem? Is there another device somewhere between the check valve/AAV and the nozzle. What seems strange is that the PEX lines that rise up under the sink are red but the PEX line that feeds the flush nozzle is blue. It is routed from the flush nozzle back up over the frame and I assume connects somewhere to the red PEX line that comes from the check valve.

This is a mystery to me and the only way to access the lines is to remove the large white panel in the service bay. I have done that three times in the past and there is no way we are going to do that while out on the road. For now we are adding water to the black tank using the toilet.

Thanks,

Bob

[mccrob]

When mine stopped up like that I blew air back through it big chunk of crud came out all was fine

[Old-Biscuit]

Water comes in via the hose connection then goes up (minimum of 2' above top of black tank) into the BOTTOM of the anti-siphon vacuum breaker device.
Then the water goes out the side of the 'vacuum breaker' device and down to black tank.....to nozzle

There is NOTHING between vacuum breaker and nozzle
You have water up to anti-siphon vacuum breaker device......YES?
You have water coming out of anti-siphon vacuum breaker device.....YES?
Then nozzle is clogged up again

BUT if you do not have water coming out of vacuum breaker device...then it has failed

[nodine]

Originally Posted by Old-Biscuit

Water comes in via the hose connection then goes up (minimum of 2' above top of black tank) into the BOTTOM of the anti-siphon vacuum breaker device.
Then the water goes out the side of the 'vacuum breaker' device and down to black tank.....to nozzle

There is NOTHING between vacuum breaker and nozzle
You have water up to anti-siphon vacuum breaker device......YES?
You have water coming out of anti-siphon vacuum breaker device.....YES?
Then nozzle is clogged up again

BUT if you do not have water coming out of vacuum breaker device...then it has failed

You failed to read my post carefully. The diagram you posted is only the recommend connection and my not represent what Monaco did. I removed the PEX line connected to the nozzle and no water comes out. I left the connection loose and went to the other side and turned the water on and came back to the nozzle side. One drop of water about every 5 seconds and that was it. The nozzle is not in the picture. Also the vacuum breaker and associated check valve are not in the picture because I have temporally replace them with a straight piece of hose (item 3 in the diagram). And note that water comes out of the feed connection to item #3 when the vacuum breaker is removed. I would not expect anything to be between the check valve and the nozzle but there is definitely a blockage and it happened over night.

I thought maybe someone with a similar coach has ran across the same problem and could advise me. Monaco could do some strange things and they my have hidden something in the belly of the service bay above the tanks.

Bob

[windsorbill]

Originally Posted by nodine

You failed to read my post carefully. The diagram you posted is only the recommend connection and my not represent what Monaco did. I removed the PEX line connected to the nozzle and no water comes out. I left the connection loose and went to the other side and turned the water on and came back to the nozzle side. One drop of water about every 5 seconds and that was it. The nozzle is not in the picture. Also the vacuum breaker and associated check valve are not in the picture because I have temporally replace them with a straight piece of hose (item 3 in the diagram). And note that water comes out of the feed connection to item #3 when the vacuum breaker is removed. I would not expect anything to be between the check valve and the nozzle but there is definitely a blockage and it happened over night.

I thought maybe someone with a similar coach has ran across the same problem and could advise me. Monaco could do some strange things and they my have hidden something in the belly of the service bay above the tanks.

Bob

Bob,

In a previous life, I had a toy box. The backflow had failed similar to your description. A part of the backflow broke off and went into the pex leading to the spray nozzle in the black tank. It lodged itself on a 90* fitting. When we tried to flush, it would run for a couple seconds then clog up again. Finally took an air hose and connected to the pex by the spray nozzle and took out the back flow and blew out the broken plastic piece. I'm certain it was getting lodged in the first 90 fitting after the back flow.

All was good after that.

[nodine]

Originally Posted by windsorbill

Bob,

In a previous life, I had a toy box. The backflow had failed similar to your description. A part of the backflow broke off and went into the pex leading to the spray nozzle in the black tank. It lodged itself on a 90* fitting. When we tried to flush, it would run for a couple seconds then clog up again. Finally took an air hose and connected to the pex by the spray nozzle and took out the back flow and blew out the broken plastic piece. I'm certain it was getting lodged in the first 90 fitting after the back flow.

All was good after that.

Bill,

I am on the same path and just returned from Home Depot where we purchased items to connect my small compressor to the line that connects to the flush nozzle. Hope it is like you said an a small piece will blow back out the other end.

Thanks for your reply,

Bob

[nodine]

I removed the PEX water supply line to the flush nozzle to prepare to connect an air compressor and noticed crud in the small hole of the PEX fitting. Pushing a awl up and wiggling it around dislodge more crud and water flowed out. It was a surprise that matter from the black tank had traveled up the nozzle and plugged the PEX line. I suspect the crud has been building up over time and finally managed to plug the line.

Bob

[windsorbill]

Originally Posted by nodine

I removed the PEX water supply line to the flush nozzle to prepare to connect an air compressor and noticed crud in the small hole of the PEX fitting. Pushing a awl up and wiggling it around dislodge more crud and water flowed out. It was a surprise that matter from the black tank had traveled up the nozzle and plugged the PEX line. I suspect the crud has been building up over time and finally managed to plug the line.

Bob

glad you found it,.

[Bob_C]

How high up in the tank is the flush mounted?

[nodine]

Originally Posted by bob caldwell

How high up in the tank is the flush mounted?

If you are referring to the flush nozzle, it is mounted in the top of the tank. When traveling with contents in the black tank, which we sometimes do, the liquid will slosh around and contact the nozzle. A number of years ago the nozzle became plugged so I removed it and drilled out the holes to a larger size. That may be allowing more solid matter to push past the nozzle into the PEX line. Now that I know what it is going on, checking the PEX line for solid matter will be a yearly maintenance step.

Bob

[RamiDav]

Nasty subject but a really good thread . lol
Nodine and WindsorBill etal has saved future searchers possible hrs of
perplexing head scratching .
Thanks guys .

Ray

[Knappicus]

New member here and my first problem to search for (black water tank flush not flowing). I may have a solution to "my" problemo now. Thanks all!

[rlbow43]

Originally Posted by nodine

If you are referring to the flush nozzle, it is mounted in the top of the tank. When traveling with contents in the black tank, which we sometimes do, the liquid will slosh around and contact the nozzle. A number of years ago the nozzle became plugged so I removed it and drilled out the holes to a larger size. That may be allowing more solid matter to push past the nozzle into the PEX line. Now that I know what it is going on, checking the PEX line for solid matter will be a yearly maintenance step.

Bob

I drilled out the holes in my nozzle a few years ago after cleaning the nozzle out 2-3 times. No problem since. But I did make another adjustment. I try not to let the black tank fill to where the nozzle is covered by the contents. I think the paper that has been disintegrated and just floating in the goo works its way into the nozzle and eventually enough of it will plug the nozzle. Whatever, haven't had a plug-up for some time and that helps me to be a happy boy!

[Burgy]

I just had the same thing happen on our Dynasty, first time ever but suspect it's been a slow process that eventually blocks the elbow and pex line.

I removed and cleaned the flusher and then cut the line about midway between the floor and tank, put in a pex faucet nut and 1/2 pex to 1/2 NPT fitting.

Now I can just disconnect the line in the middle and clean it should this happen again.

BTW
Anti-siphon valve was in the rear sink cabinet on our Dynasty, easy to remove and inspect.