Community Forums

Jerry Burks · 05-27-2021, 10:00 PM

On our new 5th wheel there is quite a bit of plumbing between the hidden valves and the drain cap. I had the unpleasant experience when after traveling and taking off the drain cap, there was an apparent pressure build-up (maybe temperature change) and I got sprayed with a mix of mostly gray and probably some black water that remained in the pipes after dumping. Not so nice but nothing a shower and a washing machine can't fix...
To avoid the pressure build-up I removed the o-ring from the drain cap. Obviously that will lead to a little dribble of this residual water on the road (maybe a cup or less) but I guess spraying that on the camp site is not preferable as well, disgusting and less healthy.
Any other ideas how to improve this?
Tnx, JB

HarryStone · 05-27-2021, 10:05 PM

Unless you have a knife valve leaking. I can't imagine why you would have pressure buildup in the pipes, if they are empty, but not having a 5th wheel, can't speak from experience.

RVnAggie · 05-27-2021, 11:37 PM

Sounds like a valve might be leaking, or at least in the one instance leaked because it didn’t close completely.

I actually added an additional knife valve on my outlet as an added piece of insurance as I seem to sometimes have about 1-2 cups of water that get by the valves that are farther upstream.

There are twist on versions or you can by the valve and couplings and glue it directly on the outlet, and still use your existing cap. I did the latter b/c the twist on valves were backordered at the time........cheap and easy to so.

TXiceman · 05-28-2021, 01:47 AM

Easy solution is to add a third valve at the out let.
https://www.rvupgradestore.com/3-WAS...BoCdd4QAvD_BwE

Ken

wildtoad · 05-28-2021, 04:36 AM

Had same problem with my MH. As delivered, the dump pipe had just a cap. One day removed cap and was greeted with a big mess. I added not only the valve pointed to in this post, but also a clear elbow to better align the pipe over the access hole and to see when clear water flows when flushing.

Quote:

Originally Posted by TXiceman

Easy solution is to add a third valve at the out let.
https://www.rvupgradestore.com/3-WAS...BoCdd4QAvD_BwE

Ken

charliez · 05-28-2021, 05:53 AM

If you don't address your leaking valves, you'll soon learn the word stink pickle. It can be anything from bad seals, cable or whatever device is used to open and close it not setup right, to debris in the tank. Could be debris from manufacturing. When I got my current TT, because I've been through this before, I filled all my tanks up with clean water and checked for leaks and proper operation. I ended up flushing a sample bottle of the blue potty treatment out of the black tank. Had I not done this, this could have easily blocked the tank from draining when full of the real stuff. The good thng is to simply learn about this stuff so you know what to do and how to handle these issues.

For a real life example, watch this short vidga....

https://youtu.be/pj2Y8NXck_c

charliez · 05-28-2021, 05:56 AM

Hopefully you still have the o ring and you can put it back once the issue is resolved

chunker · 05-28-2021, 06:06 AM

Just a thought but it's likely not a leaking valve but waste water that makes it's way to the end cap. My Raptor and GF's 5th wheel have 4 waste tanks, 1 outlet pipe and a lot of pipe between some of the valves and the outlet. Residual waste remains in the piping between the valves and end cap which while traveling migrates to the end cap and the resultant nasty surprise. On the Raptor I also added the extra gate valve. That valves traps the "migrant waste" so I don't get that surprise. If there is room you could put a short clear section between the RV outlet and the added extra gate valve to see what's there before taking the cap off.

Keep the last gate valve clean. In other words, don't close it with visible solids coming out. Make sure that it's clear waste water so solids don't get pinched between the gate and slot in the valve.

Elwood58 · 05-28-2021, 06:52 AM

There is likely a little bit of debris stuck at the gate valves. Do a drain and a good flush. With gate valves open, try to reach up with a soft brush and clean things up.

This is one of those areas of an RV that you want to work as perfectly as possible.

egwilly · 05-28-2021, 07:15 AM

All of the tanks are vented. There should be no pressure buildup.

You most likely have a bad drain valve. I had to replace our black valve 3 years into the ownership of our new trailer. They fail.

I also installed a Valterra valve at the termination of the pipe. Best investment I did for my drain system.

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Jay D. · 05-28-2021, 08:49 AM

your problem is a bad valve or not closing completely i had the same problem with my T/T cable operated valves. and just wouldn't close completely even with new parts. i installed a clear drain connection at the end with a garden hose connection. if i saw fluid i would drain it through the garden hose fitting before opening the main cap. this worked, but the garden hose fitting would plug up most of the time. this situation really sucks! i finaly got under the T/T with Sawzall and cut the plumbing off right at the tanks, and redid it with rod operated valves. how sweet it is now, almost a pleasure. everting works perfect.
Jay D.

Nwcid · 05-28-2021, 09:58 AM

Like others have mentioned I added a valve right at the end of the piping. I did not add "twist" on since it would hang down too low on my unit. I cut the original end off and glued on a new valve.

I mainly did this so that I could easily combine my 2 grey tanks since we mostly boondock. It does have the great advantage of no surprises.

Jerry Burks · 05-28-2021, 12:50 PM

Thanks for the replies. I think I did not explain the effect correctly. I am sure the gate valves for the tanks are fine. There is no leak as such when they are closed. Actually they and the cap are sealing perfectly, otherwise there would be no air pressure in the drain pipes. I believe the pressure build up comes during the day, e.g. I drained the tanks in the morning when cool and then closed the valves and the cap. During the day when it gets warmer the air in the empty drain pipes (they are probably 10+ feet long from all 3 tanks) warms up and expands and, with valves and cap closed just build pressure. It is not much and when the cap was opened it just made a short "pfft" like a soda bottle was opened. But that was sufficient to blow the residual water that had collected on top of the cap all over the place (i.e. over me). Without the pressure it would have just dribbled out (let's say a few spoonful).

The twist-on valve would shurely be the solution but the drain on my 5th wheel is hanging already very low so that is not possible. Maybe I have to tweak the drain plumbing to get an outlet valve permanently installed near the cap. It would be nice if there was a T-fitting with an integrated exit valve. Anybody seen something like that?

Or maybe I can tap a vent in the drain with a hose going up high in the camper?

Nwcid · 05-28-2021, 12:56 PM

Quote:

Originally Posted by Jerry Burks

The twist-on valve would shurely be the solution but the drain on my 5th wheel is hanging already very low so that is not possible. Maybe I have to tweak the drain plumbing to get an outlet valve permanently installed near the cap. It would be nice if there was a T-fitting with an integrated exit valve. Anybody seen something like that?

As I said in my post, I had the same problem where are twist on is not practical. It was a 5 min project to cut the current bayonet fitting off and install a glue on one in its place. I cut the pipe back enough so that I would have room to cut it again if needed, but is actually shorter than "OEM". Works great.