Fuzion 430..dual black tanks..best way to flush?

[uraceulose]

2021 1/2 Fuzion 430.

Has 88 gallon black capacity but I’m pretty sure it’s two 44 gallon tanks. 2 separate gate valves with single discharge outlet.

When I use the tank flush feature you can audibly hear the flush motor running under the front bathroom sink as well as hear what sounds like some type of a sprayer nozzle/sprinkler head down inside of the front black tank.

I also added a little gauge to the end of the hose faucet and typically I’ll let it run to about 40 gallons then pull the valve and repeat 2-3 times until the water is fairly clean.

Will the tanks over spill into one another?


What’s the best way to flush out the rear black tank?

Thanks so much,

Donnie

[flybouy]

Welcome to the forum. That's not a motor you hear under the sink, that is an anti-siphon valve. The two tanks are not connected internally, if they were there would only be one sewer hose outlet. As to flushing the rear tank look carefully for a hose connection on the outside of the camper around the area of the rear tank. It could be on the side of the camper with a plug in the fitting or it could be behind a small hatch door.

If the rear tank doesn't have a flush attachment you have a couple of choices.
1. Install or have someone install a tank flush.
2. Reverse flush it with a device that adds water thru a gate valve with a water connection built in. Flush King is one brand.
3. Use a "tank wand" which involves dragging the wand connected to a water hose into the bathroom and inserting it into the toilet.
4. Use the GEO method of mixing Dawn, water softener and pour it down the toilet with about 5 or 10 gals of hot water. Then drive home. The sloshing water and detergent will help wash off the tank walls.


I think as many others do that the regularly using the GEO method is best. A word of CAUTION: do not flush the tanks with the drain valve closed. There's many stories of folks doing this and becoming distracted or forgetting and the tank fills up and either ruptures the tank or blows out of the toilet seals. That's a mess that is not only nasty but will tie up your trailer for months if you don't do the repairs yourself.

[wiredgeorge]

If you integrated flush doesn't get to one of your two tanks, I have an older camper without a black tank flush and use a magic wand to keep my black tank clear. I am not sure if just using some detergent will work over the long term and think it best to clean mechanically with a wand.
https://www.amazon.com/Valterra-A01-...2189749&sr=8-9

[JRTJH]

Some "dual black tank designs" (trailers with two toilets) have independent flush systems, one for each tank.

Other designs have a "dual black tank flush system" that flushes both tanks at the same time. Some of those have a valve to direct waterflow, others just fill both tanks at the same time.

Other designs have a flush system on the front tank (closest to the convenience center) and no flush capability to the rear tank.

Which "plumbing system" is in any particular trailer may be dramatically different from year to year or even from month to month, depending on parts availability on the line and "design changes based on front office input"...

So, a "hard look to confirm" just how YOUR trailer is plumbed is vital....

I can't think of much "nastier surprise" than to be at a campground, cleaning and flushing the front tank with the rear tank disconnected and valve closed and at "40 gallons on the meter" hearing a loud "thump" from the rear of the trailer and a quick peek under the side reveals "brown goopy crap dripping from the coroplast".....

Or, not having the rear tank connected to the sewer at home, flushing the front tank, and when the "handy meter reads 40 gallons" and you suddenly realize "there's brown goopy crap all over the driveway, running down into the street"......

Knowing "EXACTLY" how your trailer is plumbed and where water is going when you connect the black tank flush hose and turn it on, is VITAL.... I've seen way too many trailers "just like my buddy's last year model" that provide their new owner with way too many "but that's not like mine" moments......

With Keystone these days, it's no longer "trust but verify"... It's turned into, "hope it's right and verify".....

[uraceulose]

Thank you all so much for the replies, I got one of those wands coming and I will get the “under body guard” (coroplast) pulled down and figure out if by chance the flush is actually filling both of the tanks at the same time or one after the other.

The weird part is I’m on of those guys who ran a new 50 amp circuit and plumbed a sewer line dump connection right at the discharge so I can be fully hooked up at all times at home, keep an extra fridge going and primarily only ever dump my black tanks at home.

So I literally sit there and watch the gauge, set a timer on my phone and still make it a point to hang in the backyard and stay close.
At 40-45 gallons I KNOW it’s good.
The tank reads from empty to full on the iN·command screen, there is never ANY drips or spillage anywhere.

One time I let it run to 50 gallons (remember 88 gallon black capacity with 2 separate black tanks)…my thinking is that each tank is 44 gallons. At 50 gallons there was still nothing spilling over. Nothing.

I let it run some more and couldn’t do it because I chickened out (thinking it could overflow) BUT I really think the overflow will fill the other black tank BEFORE overflowing out of a vent somewhere

[chuckster57]

“Overflow”? I’ve never seen an overflow on any rv waste tank. Easy method would be to open the gate valve on the second black tank, using a clear connection. Turn in the rinser and watch

https://www.amazon.com/Camco-Sewer-H...dDbGljaz10cnVl

[travelin texans]

Originally Posted by chuckster57

“Overflow”? I’ve never seen an overflow on any rv waste tank. Easy method would be to open the gate valve on the second black tank, using a clear connection. Turn in the rinser and watch

https://www.amazon.com/Camco-Sewer-H...dDbGljaz10cnVl

Yes! They have an overflow, actually a couple..........the toilet &/or the roof vent!
I myself prefer that neither of these be tested.............again!
JUST FYI! If you've overfilled the black tank, DO NOT, I repeat DO NOT step on the toilet flush pedal until you've drained a considerable about from the black tank.
Don't ask how I know these things!