Black tank valve

bipolarcoder

Senior Member
Joined
Oct 29, 2023
Messages
188
Location
Owensboro
Noticed the tank wasn’t filling up through the toilet for a couple days and thought maybe we weren’t just using it as much. Went to open the valve and nothing happened but there was stuff in the hose. Did the valve crack? Did I not have it pressed in enough?

It’s always something
 
Depending on your procedure for draining the tank, you could have had some "debris" in the valve gate and it prevented it from closing all the way.

The issue now is that if all the liquids drained out, it left all the solids in there to harden in your tank. If you are at a full hookup site, I would suggest aggressively flushing the black tank to ensure that you have it as clean as can be and while it is flushing, work that valve in and out gently, not fully closing it to avoid jamming the valve guides with "debris". Once you think it is good and clear, close the valve all the way and have someone run water in the toilet or operate the tank flush until you have a good amount of water in there and see if the valve is holding.

After watching my brother get a brown shower when he removed the drain cap on his one day, I decided to add a Valterra termination valve on the sewer outlet so that even if the tank valve(s) leaked, the valve would hold everything in. It also doubles as an equalizing valve so that I can open both grey tank valves and let them "share" capacity between the bathroom and galley grey tanks since the kitchen fills 10x faster than the bathroom grey.
 
Depending on your procedure for draining the tank, you could have had some "debris" in the valve gate and it prevented it from closing all the way.

The issue now is that if all the liquids drained out, it left all the solids in there to harden in your tank. If you are at a full hookup site, I would suggest aggressively flushing the black tank to ensure that you have it as clean as can be and while it is flushing, work that valve in and out gently, not fully closing it to avoid jamming the valve guides with "debris". Once you think it is good and clear, close the valve all the way and have someone run water in the toilet or operate the tank flush until you have a good amount of water in there and see if the valve is holding.

After watching my brother get a brown shower when he removed the drain cap on his one day, I decided to add a Valterra termination valve on the sewer outlet so that even if the tank valve(s) leaked, the valve would hold everything in. It also doubles as an equalizing valve so that I can open both grey tank valves and let them "share" capacity between the bathroom and galley grey tanks since the kitchen fills 10x faster than the bathroom grey.

Flushing and adding a flush king valve to the pipe for an extra back up was my idea but my wife informed me we are at a no flush campsite for the next couple weeks.
 
Turns out our valve is just ‘sponges’ and wasn’t pushed all the way too causing the leakage. I pressed it closed fill the tank and dumped it twice then filled with a couple gallons and treated since we can’t flush here.

Thanks for the help though
 
The other advantage of a termination valve is "backwashing" the black tank with gray water. My experience is that draing the black tank, then close the termination valve and open the gray valve. The inrush of reverse flow can often dislodge debris in the groove of the black tank valve as well as the elbows and floor of the tank.

After the gray & black tanks stabilize, open the termination valve and let it drain. Depending on usage, I'll do this proceedure a few times a season. Typically, at min. on the last dump of the season. After doing this method, I'll fill the gray tank with hot soapy (Dawn) water with some fabric softener and repeat the process. It's worked for me, YMMV.
 
Noticed the tank wasn’t filling up through the toilet for a couple days and thought maybe we weren’t just using it as much. Went to open the valve and nothing happened but there was stuff in the hose. Did the valve crack? Did I not have it pressed in enough?

It’s always something

The valves can be "spongy" as you suggested. I always felt I may be pushing on it too hard and something like a wad of tp or "something else" may be keeping it from doing a full close. But once I figured that out it's been smooth emptying now.
;)
 
The other advantage of a termination valve is "backwashing" the black tank with gray water. My experience is that draing the black tank, then close the termination valve and open the gray valve. The inrush of reverse flow can often dislodge debris in the groove of the black tank valve as well as the elbows and floor of the tank.

After the gray & black tanks stabilize, open the termination valve and let it drain. Depending on usage, I'll do this proceedure a few times a season. Typically, at min. on the last dump of the season. After doing this method, I'll fill the gray tank with hot soapy (Dawn) water with some fabric softener and repeat the process. It's worked for me, YMMV.
This is an interesting idea. Aren’t you worried about the black getting into the grey tank. Also when you open the termination valve do you leave both black and grey open?
Thanks
 
No concern for it "backing into the gray tank". Start with both tanks full. The procedure is drain black tank then close the termination valve leaving the black tank valve open. Open the gray tank valve and the tanks will equalize with fluid. Close the gray valve and open the termination valve to drain the black tank. Then close the black tank valve and open the gray tank valve to flush out the hose. Close all valves when finished.

You can repeate the process by filling both tanks with fresh water. As this uses a lot of water I typically do this at the end of the season before winterizing.
 
I agree. The grey tank is like a free tank flush with water already on-onboard. Also, I don’t know about you, but to me grey tanks almost smell worse than black tanks, so a cross contamination issue is a non issue.
 
The other advantage of a termination valve is "backwashing" the black tank with gray water. My experience is that draing the black tank, then close the termination valve and open the gray valve. The inrush of reverse flow can often dislodge debris in the groove of the black tank valve as well as the elbows and floor of the tank.

After the gray & black tanks stabilize, open the termination valve and let it drain. Depending on usage, I'll do this proceedure a few times a season. Typically, at min. on the last dump of the season. After doing this method, I'll fill the gray tank with hot soapy (Dawn) water with some fabric softener and repeat the process. It's worked for me, YMMV.

I do this procedure EVERY time I dump my black tank. I can often backflush 3 or 4 times with the grey water, if the grey water tank is full enough. Of course, between each black tank dump, the grey tank is closed, saving more water for the next back flush.

I'll add the Dawn and a couple gallons of water when we travel between sites.

I've been doing the back flush every time I dump for at least 20 years now, every time. Never miss.

Occasionally, I'll use my black tank flusher or the wand down the toilet bowl. But no need for this when you back-flush consistently.
 

New posts

Try RV LIFE Pro Free for 7 Days

  • New Ad-Free experience on this RV LIFE Community.
  • Plan the best RV Safe travel with RV LIFE Trip Wizard.
  • Navigate with our RV Safe GPS mobile app.
  • and much more...
Try RV LIFE Pro Today
Back
Top