Water in sewer outlet after travelling

[craigj0628]

I have a 2019 Forest River Grey Wolf 33' TT and I have an issue with water/sewage in the grey/black water outlet after travelling. I always ensure both tanks are dumped and valves are closed, bug after travelling if I take the cap off the outlet pipe liquid comes out. This happened on our last trip when I was getting ready to hook up sewer hose at full hookup site. Valves were closed but when I removed cap about a pint of smelly sewer water came out.

[Maggot]

Seal in black tank dump valve?


Leave cap off and and put bucket under drain and see what happens over a bit of time.



Maggot

[Mr. Dan]

Originally Posted by craigj0628

I have a 2019 Forest River Grey Wolf 33' TT and I have an issue with water/sewage in the grey/black water outlet after travelling. I always ensure both tanks are dumped and valves are closed, bug after travelling if I take the cap off the outlet pipe liquid comes out. This happened on our last trip when I was getting ready to hook up sewer hose at full hookup site. Valves were closed but when I removed cap about a pint of smelly sewer water came out.

My guess is that the valve may feel closed/may look closed but is not fully closed. I had that issue with my galley gray water. My valve apparatus would move until it stopped but the valve wasn't closed because there wasn't enough of the center wire sticking out of the sheath to close the valve. I ran out of slide wire before the valve closed. I had to fix it myself by trimming about 1/2" of outer sheath off my cable.


BTW, a flat bottom tank will seldom fully drain - in my experience. Level or tilted one way or the other, some 'stuff' stays in the tank at dumping -- until you drive around and out it comes when you remove the cap.

[CHICKDOE]

ditto, had the same problem. put a valterra twist on valve on the outlet and let it hold back the water that appears in the drain pipe. i think they are about $35.

it turns out my black tank valve was not trimmed properly like mr dan posted in post #3. i had it repaired and now it works just fine. but i am leaving the valterra valve on for insurance and because it allows me to equalize between the two gray tanks.

[craigj0628]

I don't have a cable assembly. Both my valves are located at the outlet and they are pushed in to the hilt. Could it be a bad gasket? I'm not real familiar with the inner workings of the valves.

[bedubya]

Originally Posted by craigj0628

I don't have a cable assembly. Both my valves are located at the outlet and they are pushed in to the hilt. Could it be a bad gasket? I'm not real familiar with the inner workings of the valves.

If it's still under warranty, RUN, don't walk to your dealer.

[jtaylor1920]

As mentioned above the Valterra valve will prevent the surprise that comes after dumping your tanks and driving around. Sometimes they just don’t get enough slope on the pipe to get all the water out. This solved my issue.

[Bama Rambler]

A lot of us (me included) use a twist on valve. I personally use the dual flush which has a clear section before the valve. That prevents surprises like you had when removing the cap.

[hupmat]

Had the same issue on black tank valve on my motorhome, a 2003. My RV Mechanic said likely TP caught in the valve slide. I filled the tank twice and drained it. That dislodged whatever was holding the slider open slightly. Good to go now, pardon the pun

[5picker]

How much liquid?

I've owned several units where maybe a 1/3 cup of residual liquid was in the piping and would come out after dumping and traveling with the cap on.

You could let the cap off all day long with a full tank and no leaks, not even a drip.

[rlh1957]

I like the suggestion of putting a bucket under the closed valve to see if it still leaks.
If you still find it leaking into bucket and you're sure it is closing all the way and seating like it should, then you need to get a new valve seal or new valve before it really fails. Drain and flush the tank well and then change it out.

[Larry-NC]

Originally Posted by craigj0628

I don't have a cable assembly. Both my valves are located at the outlet and they are pushed in to the hilt. Could it be a bad gasket? I'm not real familiar with the inner workings of the valves.

The inner workings are very simple. And you can take apart the assembly and re-assemble it without having to get new seals. Easy to take apart, inspect, and re-assemble.

See the image below. There are four bolts/nuts which hold the valve in the middle of the sandwich between two flanges. When you remove the four bolts, you can slide the valve assembly out. There are only three pieces:
--The overall assembly (Handle, gate, carrier)
--Two rubber-like seals. These are stepped; part of the seal has a larger outside diameter than the rest.

The smaller diameter of the seal seals against the sliding gate plate. The larger diameter of each seal seals against its respective flange. A talented fourth-grader can disassemble and re-assemble this valve, so don't be shy about taking it apart to clean it.

You could put new seals on if you like. Here's a link:
https://www.amazon.com/Valterra-T100.../dp/B00303XGRI

In the meantime, here's a trick. Connect the other end of your drain hose first. Then hold the second end beneath the cap, open end upward. As you remove the cap, all the waste will flow directly into the hose with no mess.

Larry

[Flybob]

Make sure the groove that the gate slides/fits in does not have foreign material stuck in it.

[Larry-NC]

Originally Posted by Flybob

Make sure the groove that the gate slides/fits in does not have foreign material stuck in it.

While you have it apart, of course.

Larry

[TitanMike]

Had this problem on my old trailer. Merely waited until the tank was empty and thoroughly flushed. Left valve wide open and used a piece of welding rod with "L" bent on end to clean the channel the valve gate slid in. Removed a gooey mass of toilet paper that was just enough to keep valve from fully seating. Got about a cup of water that was trapped in the sealed space. Didn't fill it entirely, just until enough pressure built inside cap and closed gray tank valve to hold back more water from black tank.

FWIW, same can happen if food particles build up in valve's gate "track" on the gray tank valve.

[Tall frog]

Originally Posted by craigj0628

I have a 2019 Forest River Grey Wolf 33' TT and I have an issue with water/sewage in the grey/black water outlet after travelling. I always ensure both tanks are dumped and valves are closed, bug after travelling if I take the cap off the outlet pipe liquid comes out. This happened on our last trip when I was getting ready to hook up sewer hose at full hookup site. Valves were closed but when I removed cap about a pint of smelly sewer water came out.

We also have a small amount of liquid come out of the hookup after removing the cap, my thought is the pipes don't have enough slope and won't completely drain sitting still, after moving the liquid moves on down to the cap. The valves are closed but liquid still remains in the pips.

[craigj0628]

Originally Posted by Bama Rambler

A lot of us (me included) use a twist on valve. I personally use the dual flush which has a clear section before the valve. That prevents surprises like you had when removing the cap.

Is this the Camco dual flush valve? Do you leave it connected all the time or remove it after dumping?

[Bama Rambler]

Originally Posted by craigj0628

Is this the Camco dual flush valve? Do you leave it connected all the time or remove it after dumping?

Yes it is, and I leave it connected all the time. I even put a band clamp on it to ensure that it doesn't come off during travel.

[Tundra 2014]

Try spraying some silicone spray on the metal rod on the valve. Sometimes the rod sticks a little short of closing all the way. The other choice is a twist on valve to prevent the "Surprise" or replace your valve. I know on mine, where I dump is not always level and some material will stay in the tank. I do not open valve until hooked up, 1 time was enough.