Forum Discussion

RandandDoug's avatar
RandandDoug
Explorer
Apr 10, 2021

Holding tanks

Bought a used 2019 Keystone Avalanche 321RS.
All company specs I have seen show it having 1 black and 1 grey tank.
There are two grey Pulls and one black. The salesman and I did a fairly quick walkthrough, my 3rd rv, and he explained that there are 2 grey tanks, and the that was that.
I am out today familiarizing myself with the trailer, flushing tanks and stuff, and it seems as though the bathroom sink is plumbed into the black tank, not sure about the shower yet, will be going back out to run some water through that too.
Is anyone here familiar with that? Seems strange to me, but I can live with it. Just curious and all the places to call are of course closed for the weekend.
Thanks
  • work2much's avatar
    work2much
    Explorer
    Apr 10, 2021
    Pretty common for 5th wheels to have 2 grey tanks. One for the bath and one for the galley.
  • ssthrd's avatar
    ssthrd
    Explorer
    Apr 10, 2021
    On my 2014 Laredo, there is a black (Right side) and a grey tank (Left side) between the frame rails directly under the toilet and the sink/shower. (Just repaired the grey :( ).

    There is another grey under the galley sink.......... Not sure about the fresh water tank, but I assume it is beside the grey and on the left side.

    The front tanks look to be the same size...........

    Hope this helps. Good luck getting info from Keystone.
  • agesilaus's avatar
    agesilaus
    Explorer III
    Apr 10, 2021
    Dump some dye and water down the drains one at a time and see which valve shows the color
  • wildtoad's avatar
    wildtoad
    Explorer II
    Apr 10, 2021
    Not uncommon for bathroom sink being plumbed to the black tank either due to ease of plumbing or to help assure sufficient water in the black to assure sufficient water to have things flow properly.
  • TXiceman's avatar
    TXiceman
    Explorer II
    Apr 10, 2021
    work2much wrote:
    Pretty common for 5th wheels to have 2 grey tanks. One for the bath and one for the galley.


    Not all common to have two gray tanks, but some do. It is usually when the kitchen sink and shower are on opposite ends. The bathroom sink may be routed to the black tank since it is generally low use and the black needs lots of water to operate properly.

    Ken
  • ssthrd's avatar
    ssthrd
    Explorer
    Apr 10, 2021
    agesilaus wrote:
    Dump some dye and water down the drains one at a time and see which valve shows the color


    Good idea. Two different colors of food dye.

    I forgot to say that both the shower and the bathroom sink go into the grey tank.
  • RandandDoug's avatar
    RandandDoug
    Explorer
    Apr 10, 2021
    Thanks for the responses. The labels at the pulls were wrong. Not sure why or how, but now I know so no problem. Not sure if it came like that or might have had some work done on it. And it does have two greys, but all the generic manuals and things online say one. I will be under it tomorrow, so maybe I will get some more surprises, but that's what's fun about this stuff, sometimes!! Haha
  • Roger10378's avatar
    Roger10378
    Explorer II
    Apr 10, 2021
    When the bathroom and galley are on different levels they will have separate gray tanks. If they didn't it would be easy to overfill the tank and it would leak out of the one on the lower level while you didn't realize it and keep using the one in the upper level.
  • RickLight's avatar
    RickLight
    Explorer III
    Apr 11, 2021
    I think it's not so much different levels as the distance between drains.

    The general rule is 1/4" drop per 12" run. If the drains are too far apart then they can't connect to the same outlet. Mine are about 20' apart, so 5" drop!

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