Dual waste valves on my new(er) rig - can I combine them?

Thanks Dutchmen Sport, good idea. Do you let both outlets rip at the same time?

Left is black, right is grey. I release the black first till empty, then the grey. (actually, the left has 2 tanks connected to a single outlet.)

My order for dumping, is Left (black), Left (grey), right (grey).

I have a clear elbow on the "sewer hose" that connects to the trailer outlet. This has shown that the first black dump does not get it all, even when using the tank sprayer. (Our 5er has one of those)

I have learned to close the black tank valve after the first dump and do a refill with the water from the sprayer (they warn not to leave it on too long--where "too long " is when it overflows the toilet inside I guess) Meanwhile, to save time at the dump station when there are others waiting their turns, now I dump the galley grey while refilling the black.

Close the galley grey and open the black again for the second dump--lots of white paper going by in the clear window (better than watching TV ! :) ) So this proves you need two goes at it. Three goes is not over-doing it if you want to really get it cleared out, as I have noted in the clear elbow "window".

Now you can do the main grey tank while refilling the black for a third go, or just do the grey and undo the sprayer hose and put that away.

Ok, all done except if you did a third go on the black there is no grey water left to clean out the hose, so you do that with the sani- dump's hose provided for clean-ups.

Of course if there is a big line up at the sani-dump you just do one quicky and get out of there. Do a proper job on the black tank when there is no line up.

phemens wrote:
Thanks Dutchmen Sport, good idea. Do you let both outlets rip at the same time?

THe black tank only needs to be dumped once. It's easier to just move hose vs. setting up the wye and all the other hoses.

To clarify, it looks like I have a black and grey tank on each outlet, so if I use the ‘Y’ I could run both at the same time (both black, then both grey)?

phemens wrote:
To clarify, it looks like I have a black and grey tank on each outlet, so if I use the ‘Y’ I could run both at the same time (both black, then both grey)?

Realistically you can only dump one at a time.
There is no need to ever dump simultaneously. With that in mind I just move the hose. No need to get out a wye and set all that stuff up.
In my case the only tank that I need to worry about is the grey water tank that the shower goes to. All the other tanks will last the entire trip.
I attach my sewer hose there until it's time to leave.
Then I move it to the rear connection for the galley and rear bath which are never full.
YMMV

Lantley wrote:

phemens wrote:
Thanks Dutchmen Sport, good idea. Do you let both outlets rip at the same time?

THe black tank only needs to be dumped once. It's easier to just move hose vs. setting up the wye and all the other hoses.

If you had the clear elbow to see what is leaving the black tank into the sewer hose, AND a tank sprayer, you would see that on the second go, there is lots of "stuff" (lots of toilet paper included) going by the window then too. You would never again say that the black tank only needs to be dumped once.

Of course it only needs to be dumped once if you are in a hurry, as long as sooner rather than later, you get it properly flushed out. If you don't, eventually you will be trying to unclog the whole thing by poking something down the toilet, and all that kind of fun. :(

Not quite the same but in a previous trailer I had two gray tank valves. It was a pita moving back and forth and I did run a pipe between the two and tied them together. It worked flawlessly. In my research it seemed that many of the more expensive RV's did tie them together. I don't see why two blacks would be any different. I'd give it a try. It was worth it for me.

guess i lucked out here. Mine has three holding tanks and they are all plumbed into one single dump outlet. :C