Water Pressure & Flushing - Wet Bay Issues

[Flyin4Fun]

It would be placed on the vertical wall of the black tank, as high as possible (near the top). I'll see if I can find one of my neighbors' coaches with the same system. When I do I will attach a picture

[BobJones]

That would be awesome. In the meantime I'll take a look at the vertical walls. I assumed it would be on the top of the tank which is why I took the picture that way.

[Flyin4Fun]

Originally Posted by BobJones

That would be awesome. In the meantime I'll take a look at the vertical walls. I assumed it would be on the top of the tank which is why I took the picture that way.

O.K.... My buddy let me take his apart. He has already enlarged the holes on the nozzle. Originally the holes (from memory) were about 0.050" (tiny) because the manufacturer believes it would create a pressure washer effect. In my opinion, a typical residential water supply doesn't provide enough volume or pressure to get any real benefit through such tiny holes.

This system works best with a higher volume of water to flush the tank; so long as the holes aren't too big, and the streams of water still reach the sides of your tank. Everyone I know has enlarged their holes to whatever they felt was appropriate (as discussed earlier).

[Flyin4Fun]

[BobJones]

That's awesome - thank you very much for looking into it for me as well as the great description earlier as to what the common issues are. This does make me wonder though, where the heck is my nozzle?

I'm starting to think that perhaps it's on the wet-bay side but tomorrow I'll take the passenger side cover off again and take another look. Thing is, I saw no line for it nor the nozzle......

[EdInArk]

In post number one, the anti-siphon valve is on the fresh water. And since it's designed to stop back flow from contaminating the fresh water .... what's the point?

[Flyin4Fun]

Because most people don't have a machine shop or welding capabilities, I took a trip through a local big-box store today and did some "aisle engineering". For less than $12, these 3 components should perform quite well as compared to the common system that is presently installed in RVs. In this example, my only concern is using copper in an environment with raw sewage. I don't know what to expect as far as corrosion, but I doubt it will lead to fouling problems any worse than the "high-tech" PVC components used in most systems.

Forgive me for not taking the time to explain precisely how these components are configured. I would like to believe that most people who have seen how these flush systems work will readily understand how to put this nickel & dime kit together; as well as the benefit derived from being able to quickly and easily remove the nozzle when it has fouled.


1" FNPT Pipe Flange:


This is a 1" MNPT Liquid Tight Cord Connector / Cord Grip. The Grommet is capable of accepting sizes of 0.500" thru 0.625":



The following pic is copper pipe with a closed-end. It is used in household plumbing systems to eliminate water hammer when a valve is suddenly shut off. In our application, it's being used as the stub that will have several holes drilled in it to spray water in all directions inside the Black Tank


I'm sorry, I don't actually have the pipe flange in my possession to show all components assembled. You'll have to use your imagination :-)

Voila'


One suggestion... I placed a ball valve just prior to this "thru-the-wall" spray nozzle. It makes it easy to shut off the water while removing the nozzle for cleaning. Then, turn the water on to aide with cleaning. It just makes life easier during the cleaning process. That's all for now... No applause - just send money [emoji12]

[Flyin4Fun]

Originally Posted by BobJones

That's awesome - thank you very much for looking into it for me as well as the great description earlier as to what the common issues are. This does make me wonder though, where the heck is my nozzle?

I'm starting to think that perhaps it's on the wet-bay side but tomorrow I'll take the passenger side cover off again and take another look. Thing is, I saw no line for it nor the nozzle......

Bob, it's possible that the spray nozzle is directly behind the hose connector in the wet compartment. I've seen installations like that before. If your tank isn't extremely long (full width of coach), then it doesn't really hurt to have the flush system at the same end of the tank as the drain. The nozzle will shoot the water to the other end of the tank anyway. Frankly it has a lot more to do with the ambition of the technician who performed the installation rather than finding the ideal location to install the nozzle to achieve best performance. (Whatever is easier)

If you are certain that your system used to work, then it's obvious that water was able to find its way into the tank somehow... It has to be there somewhere! Good luck!

[Flyin4Fun]

Originally Posted by EdInArk

In post number one, the anti-siphon valve is on the fresh water. And since it's designed to stop back flow from contaminating the fresh water .... what's the point?

I'm sorry, I may not understand your question. What's the point of the anti siphon? If that's the question... The anti anti-siphon / vacuum break is essentially a Fail-Safe component that really only comes into play when/if the residential water supply is temporarily out of service (or otherwise has a relative negative pressure as compared to the black tank flush line). If the fresh water supply line has no pressure or lower pressure then your flush line, and if the faucet is still open, it creates an opportunity for raw sewage to backflow into the water supply line. This is not desirable for obvious reasons.

Let me know if I didn't address your question properly.

Edit:

I think I have a better understanding of your question. You're wondering why the anti siphon is on the faucet attached to the freshwater tank. One reason is that people could use that faucet to attach a hose to their black tank flush kit. Then, everything I explained above comes into play.

But, more than that, almost every jurisdiction has a code requiring all Municipal Water Supply outlets ("Taps") to have backflow preventers. Regardless of whether or not there is a black tank attached to a hose and the water supply -it is therefore more common concerns such as storms and flooding. When a hurricane strikes, often the Municipal Water Supply goes down. If people left their faucets open - these water lines would be an easy route for everything that's floating in the flood water to get into the fresh water system. As I mentioned, it is intended to be a Fail-Safe component for situations that can be thought of as well as the unknown. It's a device designed to protect the Integrity of the water supply and its distribution system.

[EdInArk]

Originally Posted by Flyin4Fun

I'm sorry, I may not understand your question. What's the point of the anti siphon? If that's the question... The anti anti-siphon / vacuum break is essentially a Fail-Safe component that really only comes into play when/if the residential water supply is temporarily out of service (or otherwise has a relative negative pressure as compared to the black tank flush line). If the fresh water supply line has no pressure or lower pressure then your flush line, and if the faucet is still open, it creates an opportunity for raw sewage to backflow into the water supply line. This is not desirable for obvious reasons.

Let me know if I didn't address your question properly.

Edit:

I think I have a better understanding of your question. You're wondering why the anti siphon is on the faucet attached to the freshwater tank. One reason is that people could use that faucet to attach a hose to their black tank flush kit. Then, everything I explained above comes into play.

But, more than that, almost every jurisdiction has a code requiring all Municipal Water Supply outlets ("Taps") to have backflow preventers. Regardless of whether or not there is a black tank attached to a hose and the water supply -it is therefore more common concerns such as storms and flooding. When a hurricane strikes, often the Municipal Water Supply goes down. If people left their faucets open - these water lines would be an easy route for everything that's floating in the flood water to get into the fresh water system. As I mentioned, it is intended to be a Fail-Safe component for situations that can be thought of as well as the unknown. It's a device designed to protect the Integrity of the water supply and its distribution system.

Yep. After your edit was my puzzlement. Why's it on the fresh water input? And I wondered why it'd ever be necessary.

Thanks

[oneknight]

I did mine with Camco Tornado sprayers. They rotate! Clean really good.
Dropped them down from the top, 2 each in the gray and black tanks, with new separate inputs and backflow valves.
http://amzn.to/2FJAdWV