Dumping Vintage Black Tanks

[kidjedi]

I want to be sure I am dumping my 1975 stock black tank correctly. There is no macerator or any kind of "tank flush" that I can tell, so I just want to verify that I'm supposed to rely on gravity as the only force in dumping (and rinsing) the tank.

My 1975 Argosy 24 has a gray tank and a black tank (though they are labeled as main tank and auxiliary tank). My level sensors don't seem to work very well, but I know I'm getting close to dump time for my black tank.

Each tank has a separate sliding valve under the vehicle, and the tanks have one common outlet. I don't see a freshwater hose hookup anywhere (for rinsing). I know you can buy sewage outlet elbows with hose connectors for rinsing tanks, but the way the tanks are configured (I assume with their openings facing one another, then emptying into a singular "3" drain outlet" at a perpendicular angle), it doesn't seem like spraying water "up" the common sewer drain port would do much of anything to rinse the tanks out.

Any experienced advice out there?

[B. Cole]

The Main holding tank is your Black (Toilet tank) .
The Auxiliary ( Wash) holding tank is labeled just like that on my 77 Landyacht.
Pull your Black tank handle up first. Then the " Gray" water handle.That rinses your Black tank.
Its all gravity fed, so you want a lot of water in grey tank, to flush black tank.You basically want them full with max water, or like 3/4 full, to flush.
For new people, at a camp ground , never leave the handles up.
Always close until next dumping.If you leave the handles up ( common newbie mistake) that allows sewer gas from camp ground system to enter your trailer.

[Bill M.]

I use a simple approach. I keep both valves closed until time to dump. Make sure the dump hose connections are tight. Then open the black tank valve all the way. Let the tank drain. If still at a campsite I go in and flush a few bowls full of water. Then close the black tank valve and open the gray water valve. Let it drain completely. Then close the gray water valve and remove the hose and put the cap on the outlet. Stow the hose. We keep our hose in a carrier mounted under the trailer that is large enough in diameter to take the hose with the fittings attached.

The hard thing about dumping Airstreams is that the fittings are so low to the ground. Picking a good spot to dump is important. I may use a dump station instead of the campsite outlet if the outlet is too high. You can dump higher than the outlet by lifting the hose but it is not much fun and the connections need to be perfect. I estimate that I have dumped close to 1000 times and it still makes me a little nervous.

I did not read your post correctly I guess. Why am I telling someone with 4 Airstreams how to dump anyway? I know nothing specific about a 1975. Neither of my 1988 tanks have flush valves. They have both been converted to Valterra fittings.

[kidjedi]

Originally Posted by Bill M.

I did not read your post correctly I guess. Why am I telling someone with 4 Airstreams how to dump anyway? I know nothing specific about a 1975. Neither of my 1988 tanks have flush valves. They have both been converted to Valterra fittings.

All my Airstream trailers have composting toilets. I've never dumped a black tank!

I've recently gotten my 1975 Argosy 24 motorhome on the road, and we used the toilet for the first time last weekend, so I am coming up on a deadline.

I appreciate the feedback. Sounds like I should dump the black first, then dump the gray and the gray will help washout the black. I may also try to run the kitchen sink for a while to be sure that gray/auxiliary tank has plenty of water for rinsing.

Thanks again!

[Piggy Bank]

Agree to use fresh water if you have that available

If you are at a dump station do this:

Dump black,
Then dump gray.
While gray is dumping, add a couple of bucket fulls of water from a bucket into the toilet.
Dump black again.
If not clear, do some more water and repeat.

[azflycaster]

When I had a 75 the grey water could never enter or flush the black tank. The grey water tank was under the floor and the black tank was on top of the floor. Nothing from those tanks ran uphill. This is the dumping sequence we used on it and still use on our newer trailer.

1. Open the black valve and dump that tank.
2. Pour around 3 gallons of water down the toilet to remove any paper products in the valve area. Filling and flushing the bowl 3 times does the same thing.
3. Close the black valve and open the grey.
4. When the flow stops close the valve, rinse and store the hose. Don't forget to put the cap on the exit pipe.

[Waipio Rim]

We run a hose into the bathroom and shoot it into the toilet once in awhile with both tank valves open. If I hold the toilet flush valve open I can see, and blast, the bottom of the black tank with the hose.

[Skhartzell]

Emptying the gray tank last does not flush the black tank, it flushes the T connector and the sewer hose. You can buy a toilet wand that has a spinning jet. Empty the black tank and close the valve. Hook the wand to a hose and stick it down the toilet. The pressurized water helps clean the sides of the tank. Then turn the water off and open the drain. Repeat until the water draining is fairly clean. Make sure you do not overfill the tank!

[Smartstream]

Actually if you grab the dump hose and lift a section of it above the black tank level, the grey water will flow into the black tank for a quick rinse. I just stand holding the hose about waist high until I hear the water rush stop, drop the hose to the ground and finish the dump.

Also if you drive around for a few minutes before dumping, it helps to break up any solids.

[azflycaster]

I personally would not do the hose lifting process. While it sounds like a good idea, it opens a possibility of allowing fecal matter into the grey water tank. It may not be a big deal, but I like to keep my stuff separated.

[InsideOut]

Originally Posted by azflycaster

I personally would not do the hose lifting process. While it sounds like a good idea, it opens a possibility of allowing fecal matter into the grey water tank.

Me either X2^.

There is also a greater risk of the fitting coming loose and getting "stuff" on your shoes, legs, waist...

We prefer the dump, fill w/water dump again method. Black tank followed by grey tank. We did add a sprayer to the tank that a hose can be hooked up to when we did our retrofit - but we only use that occasionally like at the last outing of the season or if we have 'plenty of time' to dump like at a campsite.

Shari

[azflycaster]

This did not work out well...

[Wazbro]

Originally Posted by kidjedi

I know you can buy sewage outlet elbows with hose connectors for rinsing tanks, but the way the tanks are configured (I assume with their openings facing one another, then emptying into a singular "3" drain outlet" at a perpendicular angle), it doesn't seem like spraying water "up" the common sewer drain port would do much of anything to rinse the tanks out.

Any experienced advice out there?

Those rinsing elbows can help a lot if you have a clog.

[lemley]

For cleaning the black tank I use the ice method. Put a bag of ice down the toilet. Add water. Drive to the campground (bumpy roads are good here). Drain tanks. A warning on this one... if you don’t get all the ice into the tank before you leave, make sure to warn the wife.

I also swear by Valterra Pure Power Blue for tank treatment. Eco friendly, no formaldehyde, etc. and it helps lubricate valves.

And don’t leave the black valve open at the campground. The solid stuff needs the liquid stuff to break it down and help it flow. If you leave the valve open the liquids will flow right out and you’ll end up with a pile of solids right under the toilet.

[PA BAMBI II]

Hello. The 1972 Airstream I grew up camping in did not have a gray tank, but it had, of course, a black tank. Dad didn't know it until years later when a friend showed him, but it was possible to fill the tank with (non-potable) water at the dump station without lugging buckets of water through the trailer or from the sink and down the toilet into the tank.

There was a clean-out plug, accessible through the rear access door, installed in the vent tube. This is the pipe that runs to and through the roof to vent gases and pressure from the tank. All you had to do was remove the clean-out plug, stick the hose in there, and refill with water to flush.

Not near as fancy as these new-fangled clean-out hose attachments with hurricane force, but it was quite effective nonetheless. We never had a problem with the setup in 30 years of camping.

I added a stainless steel waste water fill fitting to the exterior of my trailer and teed into the vent pipe in my Bambi II so I can flush it out this way as well.