Black tank flush

[Robertn]

Hey everybody, I just got my 2021 keystone fuzion 427. I had my second camping trip in this rig. The first camping trip we boon-docked and I waited to dump for the next weekend. However when I opened up this brand new rigs sew cover to get a bunch of poop water everywhere. There are 2 valves in the command center where you hook up hoses and stuff. Theres a black and a grey. Then there is another valve on the outside on drivers side. It looks like its labeled grey water. and on the other side there is a white valve. when i got to the campground both of those had been open. Could I have a slow black water leak or is there something that I am missing. Also the digital gauges have black tank 1 and black tank 2 as well as grey tank 1 and grey tank 2. Not sure where both tank 2s get filled from. Please help thanks in advance

[Goliath-goes]

Not sure if this helps but my 2020 381th has 2 black tanks listed as well but we only have 1. Not really sure why there are 2 listed on the control panel inside where you get readout of how full tanks are

[JRTJH]

Looking at the specs on the 427, you have (or should have) 5 valves under your trailer.

Fresh Water 94 gal
Gray Water 88 gal
Waste Water 88 gal

There are two toilets, on opposite ends of the trailer, so two black tanks, 44 gallons each and two gray tanks, also 44 gallons each.

The front black tank and front gray tank valves should be in the convenience center. There is a galley gray tank and the valve for it should be just forward of the galley slide, next to the refrigerator. That valve will be on the chassis rail, under the bottom edge of the trailer. The washer/dryer connections are in the forward closet, so the washer will drain into one of the two forward tanks. There should be a decal in the washer/dryer area that says something like, "Do not operate washer unless the gray tank valve is open" or "Do not operate washer unless the black tank valve is open"... That decal will identify which tank the washer drains into.

There will be a valve for the rear toilet, probably aft of that same sofa/refrigerator slide, also under the trailer. The rear bathroom sink will also drain into the rear black tank.

The white valve is the fresh water tank dump, so you can empty the fresh water tank.

That's a total of 2 black tank valves, 2 gray tank valves and 1 fresh tank valve.

The black tanks and the gray tanks will (or should be) identified just above the molding that separates the FILON and the J-wrap (fiberglass/metal along the trailer sidewalls). The valve location is marked by small (about 3/8") decals, just above the molding. They will look something like this photo.

[Robertn]

Thank you very much for all that info. I see the grey on the side you explained. And the white on is on that same side. Still looking for the one in the rear bathroom. If the front gets filled does it go to the second tank. Or do I have to empty them independently?

[JRTJH]

The tanks are not "interconnected"... You can modify them by installing a terminal valve on the sewer hose connection and using the tank manifold as a way to equalize the tanks. THAT IS NOT THE WAY KEYSTONE PLUMBED THE TANKS, but is a "work around" that some owners use.

So, you will need to locate all 4 holding tank valves and pull all 4 of them to drain all 4 tanks.... Keystone's "mantra: One tank/one valve.....

[Essvar]

Your 4th valve should be just behind the wheel well. I know, because I had the exact situation happen to me on my first trip. The rear bathroom has its own tank (sink/toilet both into the same tank) and it has its own valve located behind the wheels under the skirting. You’ll probably see a sticker that says Black 2 once you look for it.