Black water surprise from sewer cap

[Iowa Hawkeye]

After traveling, I removed the sewer cap and got about a quart of black water running out before I connected at a full hook up site.
This happened two separate times. My 295RL 5ver is new.

I took to dealer for some warraty service and included this complaint.
The tech said that it is the design. The valves are closing completely, but the sewer piping is more level and does not allow sewage to completely
empty even after using onboard flush. Said it is a common problem with GD 5vers
Suggested that I get an aftermarket valve and replace the sewer cap with this final valve.

I'm looking at the Valterra Flush King 45 Degree Reverse Flush Valve Attachment and thought that would be my solution.
With this valve I could also truly flush the final Black/Gray water piping between the valves and the sewer cap.

Any thoughts/ recommendations?

[jkwilson]

Many people add those valves.

[minnow101]

I see nothing has changed in that regard as my 2015 does the same thing. Many of us have had to add the additional waste valve. I find it odd that it appears its only the black water that collects in the pipe on many(if not all of our GD's). One would think that GD would change the plumbing to avoid that as it creates quite the bio hazard when you pull that cap off and human waste pours out.

[jkwilson]

I see nothing has changed in that regard as my 2015 does the same thing. Many of us have had to add the additional waste valve. I find it odd that it appears its only the black water that collects in the pipe on many(if not all of our GD's). One would think that GD would change the plumbing to avoid that as it creates quite the bio hazard when you pull that cap off and human waste pours out.

The only plumbing change you could make would be a smaller tank, higher floor or lower outlet. Things that increase slope across the tank and through the tube. None of them good.

If you have the time when dumping/flushing, you can pull the curb side tires up on some leveling blocks to help it drain better.

[FT4NOW]

If you have the time when dumping/flushing, you can pull the curb side tires up on some leveling blocks to help it drain better.

Even doing this wouldn't completely solve the problem. For example, one of my gray tanks is plumbed with the discharge of the tank on the curb side, and then it is plumbed into the main discharge header. I've had the coroplast down many times, so I am very familiar with my tank plumbing.

The main problem is the discharge header has no slope built into it. For campers with built in leveling system, you could dump all your tanks and then after raise the curb side and that should eliminate most of the excess fluid.

Then there is the route that most of us take, and just get a twist on gate valve at the main discharge; problem "solved" as best we can without major plumbing changes.


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[AustexGP]

After traveling, I removed the sewer cap and got about a quart of black water running out before I connected at a full hook up site.
This happened two separate times. My 295RL 5ver is new.

I took to dealer for some warraty service and included this complaint.
The tech said that it is the design. The valves are closing completely, but the sewer piping is more level and does not allow sewage to completely
empty even after using onboard flush. Said it is a common problem with GD 5vers
Suggested that I get an aftermarket valve and replace the sewer cap with this final valve.

I'm looking at the Valterra Flush King 45 Degree Reverse Flush Valve Attachment and thought that would be my solution.
With this valve I could also truly flush the final Black/Gray water piping between the valves and the sewer cap.

Any thoughts/ recommendations?

Most of us Grand Design owners have added the Valterra Twist-on Waste Valve just for this reason. We also were getting about a quart of "stuff" every time we opened the valve. After you add this then you will not get the messy leak before you hook up the sewer hoses.

https://www.amazon.com/Valterra-T58-...%2C312&sr=8-36

[Keebler]

One more that has installed the extra valve; works great.

I have read that some use a set screw to hold it in place. I have put mine on so that the handle is in the "3:00" position. This has the weight of the handle working to tighten the connection. This works well for me and I have not seen the need for adding a set screw.

[GrandBillie]

After traveling, I removed the sewer cap and got about a quart of black water running out before I connected at a full hook up site.
This happened two separate times. My 295RL 5ver is new.

I took to dealer for some warraty service and included this complaint.
The tech said that it is the design. The valves are closing completely, but the sewer piping is more level and does not allow sewage to completely
empty even after using onboard flush. Said it is a common problem with GD 5vers
Suggested that I get an aftermarket valve and replace the sewer cap with this final valve.

I'm looking at the Valterra Flush King 45 Degree Reverse Flush Valve Attachment and thought that would be my solution.
With this valve I could also truly flush the final Black/Gray water piping between the valves and the sewer cap.

Any thoughts/ recommendations?

Sadly, I can tell you my 2020 31MB does this exact thing. I scheduled a service for Nov to have a few warranty issues addressed and this was on the list. The tech asked me if I had more than a gallon coming out. Told her I didn’t stick around to measure as it came out. She claimed that GD is aware and if it’s less than a gallon, it’s “acceptable”. Somehow I doubt that but that was the answer given to me. I ended up cutting off the factory twist on and glued on my own twist on end with the bladex valve attached and a cap to finish it off. It does the trick and I no longer have to worry about getting S&@! by my camper. Seems like a wonky engineering design to have to worry about this if you ask me.


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[Richter]

One more that has installed the extra valve; works great.

I have read that some use a set screw to hold it in place. I have put mine on so that the handle is in the "3:00" position. This has the weight of the handle working to tighten the connection. This works well for me and I have not seen the need for adding a set screw.

I’ve also added this valve and put the handle at 3:00. Instead of set screws, I put on a large hose clamp around the hooks that go around the bayonet lugs. It’s the same system that I used for about 20 years on our former travel trailer. Simple and effective, easily removed if I need to, but can’t be unscrewed by hand if someone were so inclined. I understand that these are currently pretty much unavailable, unless you are willing to pay “scalper” prices, making them somewhat attractive to some who are lower on the food chain than most of us.

[tjndsa]

The valterra valve is a rarity however we recently ordered one from amazon and it was supposedly delivered to our post office today. Will know for sure tomorrow.