2025 320 BD - Cassette Flush Tank Volume

mx4789 · December 6

I can’t seem to quickly find an answer, or make any search engine understand what I’m am asking.
I have a 2025 320 S Boondock. My cassette toilet has a separate fill (fresh water) tank. There is a water level indicator (and fill tube) inside the cassette compartment. Does anyone know how much water the fresh water fill tank (aka the flush tank) holds? What happens if you over fill it? Where does the excess water go?
When I add water, the level indicator (a clear tube filled with water) rises but after a few seconds it settles back down to about half way.
The owner’s manual says that there isn’t a fill tank, which is either wrong or is referencing another version (which is weird since it is for my camper year/model).
Anyway, just curious and somewhat frustrated since everything thinks I’m asking about the black tank portion of the cassette, or glosses over the specs if it does mention the fill tank. TIA!

MuttonChops · December 6

The cassette internal 'fresh water tank' is not used.

Image: https://us.v-cdn.net/5021717/uploads/editor/ti/03na4eq0p0xx.jpg

No reason to think nüCamp has changed the above for later model years.

mx4789 · December 7

Interesting, that is what I saw too, but there is definitely a fill tube that holds water and fills up, and toilet runs out of water when it’s empty. I will go outside and take a picture… maybe I am crazy and it’s just not used?? It wouldn’t be the first time, lol. Hang on, I’ll be right back…

This is on a 2025 Tab 320 S Boondock. I wonder if they changed the configuration mid-year or something. I don’t know if mine is an early in the model year model, or later in the model year… or did the dealer swap it out for some reason. (My old Aliner didn’t come with a refrigerator because the dealer “borrowed” the one out of my unit to replace a defective one in another unit.) That might be the reason why the cassette door opens the “wrong way” compared to other same year model 320’s I have seen?

Mickerly · December 7

The model number is on the tag with the bar code. Use that model number and go to the Thetford website. They will have a manual for your toilet. The 402C has a freshwater tank. The 403L connects to the trailers water system. The website says 5.1 black water and 4.0 freshwater. There is a warning about overfilling, but it doesn't say why. A shortage of one model often causes a replacement with a similar model that fits.

As for the door, your are correct. The hinge normally goes in the front. I'm betting the installed it this way so closing the door may push the fill tube in. If the door was the other way and the fill tube not fully stowed, it would jam.

Parting thought: The trailer owners manual has to meet DOT requirements for certain subjects. For information of any component of an RV, consult the manufacturer of the component.

mx4789 · December 7

Thanks for the feedback everyone! I will look into it when I get back home and and have internet access on an actual computer instead of hunting & pecking on an iPhone.

mx4789 · December 7

Yep, it turns out I have the 402C model and the flush tank (Thetford's term) holds 4 gallons. Interestingly enough the instructions say not to travel with any water in the flush tank (or half full or less if not empty). Now that I know that, I will drain the tank by flushing all of the water out of it before emptying the black tank (holding tank). Then fill it on site with about 3 gallons of water so that when the flush tank is empty I will know that the black/holding tank is near or less than 2/3 full.

Here is the link to the Thetford page for this model: https://www.thetford.com/us/thetford-support/c402c-cassette-toilet/

Howdy, Stranger!

Quick Links

Categories

2025 320 BD - Cassette Flush Tank Volume

Comments