Forum Discussion

TenOC's avatar
TenOC
Nomad
May 28, 2018

Inquiring Minds -- Plumbing -- Full gray water tank

I have a North Peak 5er by Hartland. I expected that when the gray water tank became full that water would backup in the shower pan since that is the lowest drain point. However this is not what happen. When the gray water tank is full, the sink that is in use (kitchen or bath) stops draining. I like this feature because it lets me know that the tank needs to be drained. Water does NOT backup in the shower.

Question: How do they accomplish this?

7 Replies

  • Dutch_12078's avatar
    Dutch_12078
    Explorer III
    May 29, 2018
    As Old-Biscuit said, Hepvo drain traps would cause exactly the OP's situation. Think "check valve" on the shower drain.
  • rk911's avatar
    rk911
    Explorer
    May 29, 2018
    TenOC wrote:
    Only one Gray Water tank that is only one drain valve

    Shower drains into the gray water tank, because the gray water tanks fill faster when taking showers than when not taking showers.

    well, the water is going somewhere. i have two gray tanks but just one gray dump valve. if you are certain you have just one gray tank and are certain that the shower is not draning into the black tank then it would follow that your gray tank is not full and/or your tank indicators are wrong. Once you eliminate the impossible, whatever remains, no matter how improbable, must be the truth.
  • Old-Biscuit's avatar
    Old-Biscuit
    Explorer III
    May 29, 2018
    Instead of a conventional 'P' trap on shower drain they possibly used a 'Hepvo' waterless drain trap on horizontal run. Less space needed and they only allow flow one direction (internal 'duck bill' closes when no water is flowing)

  • TenOC's avatar
    TenOC
    Nomad
    May 29, 2018
    Only one Gray Water tank that is only one drain valve

    Shower drains into the gray water tank, because the gray water tanks fill faster when taking showers than when not taking showers.
  • rk911's avatar
    rk911
    Explorer
    May 29, 2018
    TenOC wrote:
    I have a North Peak 5er by Hartland. I expected that when the gray water tank became full that water would backup in the shower pan since that is the lowest drain point. However this is not what happen. When the gray water tank is full, the sink that is in use (kitchen or bath) stops draining. I like this feature because it lets me know that the tank needs to be drained. Water does NOT backup in the shower.

    Question: How do they accomplish this?

    either by plumbing the shower into a second gray tank (like our current MH) or into the black tank (like in our first MH).
  • sch911's avatar
    sch911
    Explorer
    May 29, 2018
    Shower drains to the black tank X 2

    OR

    Are you sure that you only have one Grey tank?
  • BFL13's avatar
    BFL13
    Explorer II
    May 29, 2018
    Perhaps the shower drains into the black tank. Some RVs have two grey tanks. One for the shower and bath sink and another for the kitchen (galley)

    You might be seeing the galley grey tank full, while there is still room in the shower's grey tank

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