Black tank flush schematics?

[TRN]

Is there a schematic available for the 2015 DX3? When I try to use it, I am getting a leak of clean water into the service area.

Edit: This is not a high pressure issue, the first time I tried this I had a regulator on the system at 40psi, the dialed that down to 20 and still had water leaking down from the top of the black tank.

[halla]

I dont have a schemetic, but fresh water could be coming from the tank flush line.

[fonzie]

This link shows how these are plumbed.

https://www.google.com/search?q=blac...oFvKFZy-JE6SM:

[FOURWHL]

If its leaking and not flushing more than likely the nozzle is full of crap (literally)

[TRN]

Below is a photo of the wet lines heading up into the coach. When I turn the water on, it leaks out from above, I cannot visually see where the leak is. The water is clean, so prior to going into tank. I looked under the sink and washer/dryer, looks like these lines are actually under the bedroom (likely behind the fuse box). Is there an easy way to access this area to fix the leak. Sorry about the image, the site keeps turning it sideways (Left is up).

[emm-dee]

Is any water at all getting into the black tank? If yes then it’s probably the vacuum break valve. Hundred of posts about their leak problems.

[TRN]

Originally Posted by emm-dee

Is any water at all getting into the black tank? If yes then it’s probably the vacuum break valve. Hundred of posts about their leak problems.

Can't tell, it leaks so much that I'm afraid to leave it running to check. I had hoped that the valve was under the sink, but it is not. Need to get access to it to check it out (see previous post).

[Joche]

I have the same problem with my Forest River 27RR Toy Hauler. Never have been able to
use the black flush because it leaks clean water at the connections in the kitchen cabinet.
I have changed the hose clamps and swivel fitting, thinking I had found the problem several times by hoping to see the leak when someone else turned on the water outside while I used a flashlight inside.

The only thing I have left is a black plastic valve at the junction of these water lines.
Maybe my problem and yours is the "vacuum break" valve that emm-dee refers to above..

Joe

[5picker]

Originally Posted by Joche

I have the same problem with my Forest River 27RR Toy Hauler. Never have been able to
use the black flush because it leaks clean water at the connections in the kitchen cabinet.
I have changed the hose clamps and swivel fitting, thinking I had found the problem several times by hoping to see the leak when someone else turned on the water outside while I used a flashlight inside.

The only thing I have left is a black plastic valve at the junction of these water lines.
Maybe my problem and yours is the "vacuum break" valve that emm-dee refers to above..

Joe

There are hundreds of posts about that "black plastic valve" as you call it, leaking.
Common issue.

[TRN]

So how do you access the area to get to the black plastic piece? It's not in the sink area. I did not see any easy access.

I'd be happy to know where that valve is hiding in my '15 DX3 37TRS.

[emm-dee]

Not sure about the DX but you could give them a call and find out. I called Forester about mine and they directed me to open an almost invisible access door in the bedroom closet. That door opens to see the plumbing to the shower and the vacuum valve, which happens to be directly above the black tank.

When you find it here’s a quick, cheap and permanent fix. The 90 degree fitting is installed where the valve used to be.

[Larry-NC]

Originally Posted by TRN

So how do you access the area to get to the black plastic piece? It's not in the sink area. I did not see any easy access.

I'd be happy to know where that valve is hiding in my '15 DX3 37TRS.

Hint: It has to be higher than the top of the black tank, hence above the floor inside.

Consider this scenario: You flush the tank adding some water from the downhill tap. You then turn the tap off and disconnect the hose at the tap and drop it on the ground. As the water starts flowing, it starts a siphon and the "black water" is drawn up through that loop, through your hose and out onto the ground by the tap. This is the siphon effect and could drain the entire tank. The vacuum breaker valve (anti-siphon valve) prevents this.

Emm-dee may think his solution, eliminating the valve, is clever, but it has the potential to go very badly.

[emm-dee]

Originally Posted by Larry-NC

Hint: It has to be higher than the top of the black tank, hence above the floor inside.

Consider this scenario: You flush the tank adding some water from the downhill tap. You then turn the tap off and disconnect the hose at the tap and drop it on the ground. As the water starts flowing, it starts a siphon and the "black water" is drawn up through that loop, through your hose and out onto the ground by the tap. This is the siphon effect and could drain the entire tank. The vacuum breaker valve (anti-siphon valve) prevents this.

Emm-dee may think his solution, eliminating the valve, is clever, but it has the potential to go very badly.

Since the flush fitting is located at the top of the tank the only thing it can siphon is air.

[Joche]

Unfortunately I had to follow it to the leak area. The hose connection on mine comes in from the middle area of the trailer.
Same area as the small kitchen pantry beside the slide out.
Then remove a false panel (2 wood screws) to see the plumbing connections.

Watch with a flashlight while someone turns the water on outside. Either open the window to yell stop! or use cells phones LOL

[TRN]

Found the source of the leak, it is the siphon valve which is located behind the drawers in the bathroom cabinet. Looks like I will have to remove the bedroom door to remove the drawers, then an easy fix. Will replace the plastic piece with a brass piece.

[floridela]

Originally Posted by emm-dee

Since the flush fitting is located at the top of the tank the only thing it can siphon is air.

If that were 100% true then why would you even see a back flow preventer on any RV at all?
Why would a back flow preventer be found on the hose connections to fresh water?

These are there to protect all campers from the possibility of a siphon effect causing serious illness to everyone in the campground. It might never happen, but it could happen, so why not use the equipment that is provided for our safety? A back flow preventer is relatively cheap, use it.

[Wolf Alaska]

TRN, I'm glad you started this topic.

Last week, I applied water to Fury's black tank flush fitting for 1st time. This was after dumping black tank.

Clear water was flowing from tank, however water started leaking from fore & aft edges of the black tank compartment. I tried reducing water flow from hose bib valve, but leaks continued. I discontinued the flush operation.

Having no idea where or if any water collected, I left the adjacent water compartment doors open. 712 is at about 90° during most days, so I think (hope) any water safely evaporated.

Thanks, to all who contributed. I know a lot more about the situation now.

[nomad297]

Originally Posted by emm-dee

Since the flush fitting is located at the top of the tank the only thing it can siphon is air.

I’m sure when you did this you didn’t do it with the intention of being irresponsible, but now that you know you have created what could be a deadly hazard, I’m sure you will be responsible and either disconnect your black tank flush or install the appropriate vacuum breaker.

Even though you think your flush fitting is on the top of the tank and the only thing that could get into that line is air, you are wrong. Where do you think the black water will go when you overfill your black tank? You have basically created a black tank overflow that connects directly to the potable water supply used by everybody connected to that system.

You may say “Well, I would never overfill my black tank. I know what I’m doing and I’m not that stupid”. Maybe you’re not that stupid, but what about the next guy who owns that RV? Is he going to be as smart as you? Is he going to know that he could possibly kill himself, his family and people he doesn’t even know simply because he overfilled his black tank? Are you going to warn him about this? I doubt it.

Now that you know what you know, are you responsible enough to correct this? I hope so.

Bruce

[bubbles]

Originally Posted by floridela

If that were 100% true then why would you even see a back flow preventer on any RV at all?
Why would a back flow preventer be found on the hose connections to fresh water?

Because if there wasn't one on the fresh water port water would pour out that port when the water pump is used.

[bubbles]

Originally Posted by nomad297

I’m sure when you did this you didn’t do it with the intention of being irresponsible, but now that you know you have created what could be a deadly hazard, I’m sure you will be responsible and either disconnect your black tank flush or install the appropriate vacuum breaker.

Even though you think your flush fitting is on the top of the tank and the only thing that could get into that line is air, you are wrong. Where do you think the black water will go when you overfill your black tank? You have basically created a black tank overflow that connects directly to the potable water supply used by everybody connected to that system.

You may say “Well, I would never overfill my black tank. I know what I’m doing and I’m not that stupid”. Maybe you’re not that stupid, but what about the next guy who owns that RV? Is he going to be as smart as you? Is he going to know that he could possibly kill himself, his family and people he doesn’t even know simply because he overfilled his black tank? Are you going to warn him about this? I doubt it.

Now that you know what you know, are you responsible enough to correct this? I hope so.

Bruce

Overkill. I'm with EMM-DEE