Which gray and black tanks collect which liquids in a 2025 385FL?

[johnm]

On our maiden voyage finally and was not completely prepared for a distant sewer tap. I dont have enough hose for both drains to be hooked up at the same time, so we are trying to avoid filling up one tank. My question is - which tanks collect which waste from each plumbing appliance?
In our Fuzion one black tank had both a gray and a black dumping into it (the half bath)... thus my question.
~Galley sink
~Half bath sink & toilet
~Master bath sink & shower
~Master bath toilet
Where do each of these end up? And what sewer drain to they exit from?
The rig has 2 black and one gray holding tanks. Not sure if the black tanks are tied in together or not - they have a lot of distance between them in the frame.
Any help would be apreciated - just to save me some time here on our first trip. This will be corrected before our next trip!!! lol
The pic below I believe is looking to the rear of the 385.

 

[George]

Rather than rely on inconsistent information you can use food coloring to determine which tank is which.
I don't mean "inconsistent" to be derogatory – it's just that all rigs aren't built identical in some ways.
Also try searching for "food coloring" in this forum.

 

[Ben and Kathy]

On our maiden voyage finally and was not completely prepared for a distant sewer tap. I dont have enough hose for both drains to be hooked up at the same time, so we are trying to avoid filling up one tank. My question is - which tanks collect which waste from each plumbing appliance?
In our Fuzion one black tank had both a gray and a black dumping into it (the half bath)... thus my question.
~Galley sink
~Half bath sink & toilet
~Master bath sink & shower
~Master bath toilet
Where do each of these end up? And what sewer drain to they exit from?
The rig has 2 black and one gray holding tanks. Not sure if the black tanks are tied in together or not - they have a lot of distance between them in the frame.
Any help would be apreciated - just to save me some time here on our first trip. This will be corrected before our next trip!!! lol
The pic below I believe is looking to the rear of the 385.

You can also contact Alliance support and request a waste plumbing diagram. They will require the VIN # of your 385.

The dye suggestion is a good one as well just to be sure! Our rear toilet is plumbed to the back Grey tank, a MFG mistake.

-Ben

 

[Chaseweston]

+1 on the dye method to verify. I have a DWV isometric I got from Alliance for our Valor and it shows the main bathroom lav and shower going into the gray (expected) and only the toilet into the front black tank.

In reality, the lav and toilet both plumb to the front black tank (MFG mistake) and only shower into the front gray.

 

[2 Allies]

We have a 2024 385FL and they sent us a diagram, but we only have one discharge point for the black and 2 greys. One grey collects the rear shower, rear bath vanity, the 1/2 bath vanity and the washer. The 2nd grey is for the kitchen sink only. The black collects both the 1/2 bath and rear bath toilets as the rear is a macerator toilet. Ben and Kathy is right, Alliance will send you the plumbing diagram that matches your VIN

Good luck,

 

[WE3ZS]

Same here on our ‘24 385FL.
Kitchen sink is the only feed into the forward grey tank, that exits via the forward dump connection.
Rear grey tank gets the washer, powder room sink, master bath sink and shower water. Both toilets go to the single black tank (switch panel display inside shows 2 black tanks but there is only one) and the black tank and rear grey tank both exit via the rearward dump connection.
Does the thread starter (Johnm) have 2 grey tank dump switches in the wet bay along with one black dump switch? The color and number of these dump switches should match the color and number of the associated tanks.

 

[Ben and Kathy]

I installed Barker MFG Auto Drains on ours. Fantastic support!!! I had purchased three units last year on Amazon during a sale, was delayed installing until April, discovered that one of the units was in the correct box but wrong size plumbing. Called Barker MFG, they took care of me right away. Ended up upgrading to their latest switches as well. Put the switches in the 1st rear compartment back by the rear sewer outlet. Pulled the 12v off of the compartment light feed. There was already a wire chase from the underbelly to behind this compartment.

 

[johnm]

Thanks for all the responses! It helps. I will get the waste plumbing diagram from Alliance. It seems like there are some changes from last year's model - I show 4 tanks on the control board, yet only saw three during the factory tour (pic above).
Right now based on our usage and what the control boards shows -
Black 1 tank is the rear toilet and Black 1 is the half bath toilet.
Gray 2 is the shower and sink in the rear bath.
Gray 1 and Black 2 havent registered as yet - so I assume they are the half bath toilet and the half bath sink and the galley sink... which we have used very little
BTW, Our macerator is showing a full black tank (as I have read about in other threads) - but its still working. Not sure what effect it will have, if any.

 

[Ben and Kathy]

There have always been 4 waste tank indicators on the panel. Black 2 is unused. Here's a part our 2021, unit #2, panel.