Black tank flush....

drboyd · 07-30-2003, 11:59 AM

OK, I'm hearing about "black tank flush" as a (capital C) Cool Thing on the new Airstreams.

Sounds like something that runs water into the black tank to clean it out. Duh! Ain't I the bright one?!

So here's my idea - I've got a black tank drain on the left corner of the trailer, and a vent pipe coming out of the black tank on the right corner - the opposite side of the tank.

Seems to me like water put down the vent pipe would flow across the bottom of the tank and out the drain, carrying with it any solid matter.

So, where to get extra water? How about the grey water tank? Wouldn't it be possible to put the 12 volt RV version of a trash pump to draw out of the grey water tank (setting the pickup a couple of inches from the bottom, to avoid drawing big chunks of stuff into the pump) and pump it down the vent (thru a T fitting near the bottom of the vent) to flush out the black tank?

I'm sure this has been thought of before, and proven to be a Really Bad Idea, for several reasons. I'm just curious why!

Thanks!

Don

thenewkid64 · 07-30-2003, 12:10 PM

The only reason I can think of is cost. A black tank flush system like is being installed is a $5.00 cost for parts and $20 labor cost to build it in. Who knows what the markup on it is. I do not think you really need a macerator pump. As long as you are using an impeller based pump anything that gets pulled in still gets shredded. A diaphram sytyle could get stuff stuck in the valves.

You solution sounds elegant, and should work as long as seal/mount/install it all with safety and stability in mind. I would not even worry about getting the fitting into the tank, just having it dump into the vent tube should work.

With all of that being said I would suggest some type of safety so the pump cannot move water into the black tank without the valve being open, or you not being aware. Maybe a headlight warning buzzer hooked to the power switch so you know it is on? There should be no need for a check valve as there is one in the pump.

drboyd · 07-30-2003, 12:22 PM

...on the pump, so you have to keep your thumb on it to have it run....

"Your solution sounds elegant, ..." Blush! I'm so flattered! Thanks!

Silvertwinkie · 07-30-2003, 04:10 PM

You know, what seems to work well for us is simply placing the chemicals in the tank the start to break down the stuff in there.

Then we purge that first and the grey tank next. At home, we have a sewer line poke through. I fill the tanks two times and flush them out completely.

Of course, you need a poke throught to make it work. The reason I did this was because most dump sites that I have been to don't have a threaded connector (which I thought the black flush used). Since I didn't want to drag a dumpstation hose through the Bambi, I figured I'd do it at home where I know where the hose has been and I can control some of the variables.

Eric

WayWard Wind · 07-30-2003, 08:57 PM

At the present time we are using a Flush King for our tanks. It appears to work very well & we avoid taking a fill hose in the trailer. The clear fitting allows one to see when the tanks are clean. I have been seriously considering to have a Black Water Flush added when we go to Jackson Center this Fall & talked today to A-S ( Rick ) regarding costs. It's now between the Flush or Fantastic Fan. Most likely it will be the fan, as I think the Flush King will do the "job". Also when talking to A-S today I tried to get from them what all ( meals, etc) is covered in the costs. They appeared to be REALLY unorganized for the event, as they had no idea what may be covered. They did however make a quick charge to the CC. Perhaps a Pig in the Poke?
Best,

Silvertwinkie · 07-31-2003, 07:24 AM

What was the cost of the flush? I also talked to Rick and got a ballpark on the Fantastic Fan (which for sure is going in-- I just don't know if I want two since the Bambi as poor cross ventilation.

Eric

Rickk48 · 07-31-2003, 09:53 AM

I have been using the Flush King for a couple of months and think it works really well. Totally eliminates need to drag hose into trailer, and gives a good visual check as to cleanliness of the tank.

Eric, I have only one Fantastic Fan in my Bambi, above the dinette/Galley area. With the rear vent slightly open, we get very good "all trailer" ventilation, blowing in or out. With the two vents only about 8' apart, I think two Fantastic Fans might be slight overkill (except for the rain sensing feature). On a longer trailer, I could certainly see the benefit.

Silvertwinkie · 07-31-2003, 01:38 PM

Rick, thanks for the input on your exp with the fantastic fan. I kind of get my eyes bigger than my stomach when I think of improving things!

**jcanavera** · 07-31-2003, 04:27 PM

I have 2 fans and a much larger trailer than a Bambi. My interest in two fans was purely based on volume of air. Two can exhaust more than one. Plain and simple. Two fans really wouldn't be overkill if your interest is moving air. Sometimes the motion is what keeps you cool, especially when the outside temp is pretty warm.

Jack

dtbw · 07-31-2003, 04:36 PM

I have been contemplating putting in another Fantastic Fan in our 19'. Part of the reasoning is the auto closure in case of rain as well as the added ventilation of either both pulling or a push/pull operation. Has anyone done this on a 19' Bambi yet? I am curious if there is wiring at the vent or will I just need to pull a new wire from the adjacent ceiling light.

WayWard Wind · 07-31-2003, 09:25 PM

Rick at A-S quoted me "around" $400 for the Flush installed. Said they would have to remove the belly pan for the install. I agree that the Flush King appears to work well. No hoses in the trailer & with the clear view elbow connection you can tell when the system is clean. So most likely we will go with the Fantastic Fan at $425. It will have the rain sensor, which will be nice if we need to leave the Mr. Turbo in-residence for a short period. I would think that with a 19' , leving a window open & running the fan on exhaust would be adaquate. Btw, has anyone else had problems with Rick/ A-S not returning calls? Took me 3 days to get thru to Rick, as he would not return calls, even after another worker told me he had my name ,telephone #, on his desk & was to call. When I findly talked to him, I wished I hadn't as he was very unpleasent & not really helpful. Kinda cheapens the A-S thing for me. Anyway so goes life.
Best,

dtbw · 08-01-2003, 08:40 AM

A.E.
I am surprised that A/S feels it make it easier to pull the belly pan than to work just from the lavatory area. When I had my lav area out, I could clearly see and reach all the black flush components. The inlet to the black tank is just at floor level toward the curbside wall. There is a hose that goes upto a vacuum breaker mounted on the wall just below the lav counter and then out to the outside connection. They will have to pull the lav area out anyway to do the installation of the plumbing. I will take another look at mine when I bring the Bambi home for next week's trip. Clearly the time to do the black tank is before it is installed, but given that I had no problems cutting the opening for the Thermasan probe (1 3/4") I see no reason why A/S could not do the same. I just used my right angle drill and a boring bit. I did have to angle the bit down some to get it as low on the tank as possible, but the tank is only a fraction of an inch thick, so the slight angle was immaterial. The black tank flush inlet was only a few inches away and at the same height as the opening I drilled. If I can can get some decent pics, I will send them to you. (I failed to takes pics while I was doing the Thermasan installation...stupid me)