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  1. #1

    What is plumbed to what?

    I have a 2015 388M.
    It has two black and two gray tanks.
    I believe that the rear sewer pipe is for the rear bath black tank only and is filled by the 1/2 bath comode and sink only.
    So that leaves the front drain pipe with a black tank for the main bathroom comode and two gray tanks that are drained with one handle.
    One of my gray tanks (#2) are not displaying any level so I can't determine what is plumbed to what.
    So what drains into what tank?

  2. #2
    Site Sponsor JCR GD's Avatar
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    Mar 2015
    Central Cal
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    I would think it is similar to mine but ???

    As you described for rear black and front black and then one gray for galley and one gray for shower and bath sink. But it seems like there should be two gray handles if that is the case... maybe just one big gray???
    Jim (& Sharon)
    2015 GD Momentum 385TH - SOLD
    For Sale - 2015 Ford F-350 DRW 4x4 Lariat w/ AirLift bags, Titan 65 gal. OEM replacement fuel tank.
    The toy:
    2017 RZR XP 1000 EPS SE

  3. #3
    Left The Driveway Mmeyer's Avatar
    Join Date
    Feb 2015
    North Ft. Myers
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    I've been trying to figure this mystery out myself. We've been in our 350 since the end of April without any issues. Moved her from Ohio first of July for a month in the cool air in New Mexico. after this first week or so, gray tank one always shows full even after dumping. This is no big deal since GD back-up sensor (main bath vanity) lets you know when gray one is full. We don't use the half bath much and figured the sink there would go to the black two tank. Our gray two tank always shows empty. I just read another thread where Janice from GD offered the gray two tank is for the half bank sink and for your W/D waste water. Yesterday after dumping all tanks I ran the half bath sink for 10 minutes, the black tank two registered 1/3 full. So our 350 half bath sink drains to black tank two. We don't use the W/D plumbing, needed the space for the H/D instead, so I guess I'm going to open the washer drain and run water into it to see what tank fills up. This mystery shouldn't keep us up at night but it seems too. With all the paper work G/D gives us a simple plumbing layout would be nice. With all the mod's folks do you'd hate to drill a hole threw a plumbing pipe or into a gas line or gasoline tank.
    Mark & Ang (Retired)
    2015 Momentum 350M
    2016 Ford F-350 w/18K SuperGlide/AirBags/RDS Transfer Tank
    2007 HD Ultra /

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