Sewer Cap Surprise - You are not alone

**watt100** · 09-07-2019, 02:26 PM

we had same issue on 303rls but i cut my outlet off behind twist lock and glued on the new valve and only stuck out very slightly further than the original twist lock.

**Jan&Diane** · 09-07-2019, 03:04 PM

I also added the gate valve and put small hitch pins through holes I drilled in the clips that hold the valve on since I had heard it can rotate off while traveling. So far it hasn't budged and it is nice to not have the sewer cap surprise anymore!

**Sledman248** · 09-07-2019, 04:01 PM

[QUOTwE=manofslip;254589]So I am one of the many people who have had that surprise of a bunch of water (or other) coming out of my sewer connection after knowing full well I let everything drain the last time I dumped. Now if we knew it is grey water that might be slightly OK but definitely not black water. The amount of water is generally over a pint and definitely not a small cup full. This is an unpleasant surprise I never had in previous campers. I read a lot of people having this issue and the easy solution is putting a gate valve on the sewer connection. I even had the Dealership indicate to me that this happens to a lot with the Grand Designs and they offered the same solution. So with that being said the engineer in me wanted to make sure my waste gates were working correctly. So I did a test.
• First I cleaned the pipes out using a dryer clean out brush with a rag on it. My goal was to get everything dry. I replaced the sewer cap. After a couple of days the pipe was still dry.
• The next thing I did was fill up my black tank to ¾ full. I waited 5 days. Still the pipe was dry so I figured my blank tank gate valve was working.
• The next thing I did was to fill up my grey tank. I had the same result after a few days. The pipe was still dry and no surprises.
So I am left with the fact that my gate vales are working and the problem is the plumbing after the gate valves. Water is remaining because of the slope of pipes or pockets where the water can not drain. So we could re-engineer the plumbing or just add a gate valve like everyone else. I am opting for the gate valve.

Bonus- So all of the effort was for not. Since there was clean water along with my normal tank concoction of baking soda, Calgon water softener and tank treatment sitting in the tanks for several days, my tank sensors were fully functional immediately after dumping. The 1/3 full light was on previous to my test for both tanks.

I hope this helps those who question what is going on.

Dan[/QUOTE]
What amount of Calvin and baking soda do you use for tank treatment?

**KheSahn068** · 09-07-2019, 04:12 PM

Just to see how much water I would have in my dump lines, I put five inches of wood on the Pax side trailer wheels so that the trailer would be tipped to the drivers side. This would be AFTER I had drained all tanks (2 grey and 1 black). I next put a 5' sewer hose on and opened both the grey water valves and then the black water valve. The 5' sewer hose was dumping into a 50 gallon drum I had and I filled about a quarter of the drum (which would be about 10-12 gallons. This was a mixture of all grey water and black water waste. Now the real trick was pulling the trailer off the 5 inch pads and driving in my field where I did a few turns with the trailer and low and behold, about another several gallons sloshed out. Needless to say, the Grand Designer Designers shouldn't be designing the sewer system in RV's and all should be fired for stupidity. They install sewer lines that go uphill and monitors that are about as accurate as a five year old quoting Shakespeare.

**hotpepperkid** · 09-07-2019, 05:29 PM

Originally Posted by manofslip

So I am one of the many people who have had that surprise of a bunch of water (or other) coming out of my sewer connection after knowing full well I let everything drain the last time I dumped. Now if we knew it is grey water that might be slightly OK but definitely not black water. The amount of water is generally over a pint and definitely not a small cup full. This is an unpleasant surprise I never had in previous campers. I read a lot of people having this issue and the easy solution is putting a gate valve on the sewer connection. I even had the Dealership indicate to me that this happens to a lot with the Grand Designs and they offered the same solution. So with that being said the engineer in me wanted to make sure my waste gates were working correctly. So I did a test.
• First I cleaned the pipes out using a dryer clean out brush with a rag on it. My goal was to get everything dry. I replaced the sewer cap. After a couple of days the pipe was still dry.
• The next thing I did was fill up my black tank to ¾ full. I waited 5 days. Still the pipe was dry so I figured my blank tank gate valve was working.
• The next thing I did was to fill up my grey tank. I had the same result after a few days. The pipe was still dry and no surprises.
So I am left with the fact that my gate vales are working and the problem is the plumbing after the gate valves. Water is remaining because of the slope of pipes or pockets where the water can not drain. So we could re-engineer the plumbing or just add a gate valve like everyone else. I am opting for the gate valve.

Bonus- So all of the effort was for not. Since there was clean water along with my normal tank concoction of baking soda, Calgon water softener and tank treatment sitting in the tanks for several days, my tank sensors were fully functional immediately after dumping. The 1/3 full light was on previous to my test for both tanks.

I hope this helps those who question what is going on.

Dan

I have had the same results. Seams to happen only when on the road. I get from 1/4 to 1/2 and it appears to be either gray or galley water

**gulfstreamg5** · 09-07-2019, 06:02 PM

I have the same “leak” issue on our 2019 Solitude 3740bh. Bought two of the Valtera gate valves to solve the issue... Anyone use ABS cement to “lock” the otherwise freely rotating Valtera valves in place ??

**mgm1121** · 09-07-2019, 06:09 PM

Just leave the cap off. I never get a surprise anymore.

**traveldawg** · 09-07-2019, 06:44 PM

Originally Posted by gulfstreamg5

I have the same “leak” issue on our 2019 Solitude 3740bh. Bought two of the Valtera gate valves to solve the issue... Anyone use ABS cement to “lock” the otherwise freely rotating Valtera valves in place ??

I met a fellow this summer who had fabricated a bracket to hold the valve in position and he welded the bracket to the frame. I’m going to look into this when I get done traveling.

**WhittleBurner** · 09-07-2019, 07:56 PM

If you drop the coroplast you would see that the tanks are big and somewhat shallow. They are only as thick as what the frames are. The flooring is on top of the flooring and they can't have them be below the frames. The tubes have to be at the bottom of the tanks so as to be able to empty them. The tubes then run next to them to the side of the trailer. If the tubes were run at an angle they would be too low by the time they reached the side of the trailer and would be a hazard. Even with a sleight drop the dump stations aren't always level meaning there is a good chance the tube would be on a sleight incline anyways. There isn't a good solution to being guaranteed of of not having something left in the tubes. That's why you see so many gate valves on a lot of different brands of trailers.