Tank fittings spin-welded in today

[Iceni John]

I took my black and gray tanks back to Ronco this morning (I had bought all four tanks from them about two years ago), and they spin-welded in the fittings while I waited, for free.   The black got five fittings, and six in the gray, so now it's full steam ahead to finish making these tanks' supports, then they go in the bus.   Like with the two fresh tanks, I have to jack up one side of the bus enough to slide each tank under the bodyside, then lower the bus down and manhandle the tank up into position to secure it.   Not fun!   Once they're in place they'll be completely secure, yet still accessible if needed.

Each tank has two 2" vents, but I've not yet decided exactly how to run the vent pipe.   I hate having to make a hole through a perfectly good roof, but what other way is there?   I also put a 3/4" inlet in the top of the poo tank directly above the 3" outlet, and I'll either direct city water in through it to help flush the tank and move those stubborn "solids", or I can transfer gray water through it if the gray tank fills first.   I also put a second dump valve on the gray tank kerb-side, just in case . . .

The much-awaited First Dump In The Bus is drawing near.   Maybe I should invite my friends round to share the joy.   BYOTP?

John

[Seangie]

 John,

I am right behind you.  I am ordering my tanks soon. 1st week of April.  Then installing hopefully in May.  Take pics as you progress....Id love to see how you are installing your tanks.  Mine are going into a bay so it should be straight forward but this is all new to me.  I've never owned an RV and this is our first bus.  So I am open to all suggestions.

-Sean

[mikke60]

How do you intend to hook clear water to the black tank? anything other than indirect,such as a drain would seem to be  sanitary nightmare?

[TomC]

There is nothing said that you have to run the vents up to the roof.  When I had my truck running with the fully equipped sleeper, my tanks were mounted on the fuel tank cross supports with the drive shaft above.  My vent for the gray was just a 12" open top pipe, and my black was on top of the tank with a 3ft hose leading backwards for vacuum effect going down the road.  Now in a big rig, smells isn't a big deal since you're not socializing in a campground.  With the black vent at a lower level, you can smell every time the toilet is flushed.  The smell control is why you have roof top vents.  As far as the vents are concerned, the vents don't care where they are mounted.  Good Luck, TomC

[Iceni John]

How do you intend to hook clear water to the black tank? anything other than indirect,such as a drain would seem to be  sanitary nightmare?

The black tank's 3/4" inlet directly above its 3" outlet will be supplied two ways:

  1.   City water can be connected directly, obviously with the  appropriate vacuum breaker / check valve protection to absolutely prevent any possibility of contaminating the city water supply.   This will blast city water at 65 PSI (or whatever pressure it is) straight down into the black tank to help clean it and persuede obstinate solids to not get too attached to the tank.   Just in case you were wondering, this city water inlet will be entirely separate from the fresh tanks' and bus's main city water entries (there is one on each side), so there is no possibility of cross-contamination of my fresh water.   My fresh water tanks and pumps/filters/manifold/etc are ten feet from the waste water tanks, partially for this reason.

  2.    The gray tank has a 3/4" outlet about 1" above its bottom, and this supplies gray water to a 12-volt transfer pump that will move it up to the black tank's 3/4" inlet.   Again, there will be a check valve to prevent any back-flow to the gray tank.   This will be to transfer excess gray water if my gray tank is getting full  -  it's only 115 gallons, but the black tank is 65 gallons which should last a long time before needing dumping.   This transfer pump won't have sufficient pressure to clean the inside of the black tank;  it is merely to transfer excess gray water.   I'm hoping that my Dometic 310 toilet won't need more than about a quart per flush, then my black tank will last a long time before dumping.

With 400 gallons total tank capacity my intention is for one person to comfortably manage at least one month off-the-grid, or two people for at least two weeks.   This means taking showers every night, washing, doing the dishes, in other words living a more-or-less normal lifestyle.

John  

[Oonrahnjay]

(SNIP)  this supplies gray water to a 12-volt transfer pump that will move it up to the black tank's 3/4" inlet.  

     What pump are you using, John?  (Brand, part number or name, please)   How much $$$$$?   Thanks!

[Geoff]

Warning: Just because they "spin-welded" the fittings on your tanks doesn't mean they won't leak.  Been there, done that, if I were you I would pressure test the tanks and fittings BEFORE you install them in case the welds leak.  Also, "Seal-All" works great on bad polyethylene leaks and welds. 

[Iceni John]

(SNIP)  this supplies gray water to a 12-volt transfer pump that will move it up to the black tank's 3/4" inlet.  

     What pump are you using, John?  (Brand, part number or name, please)   How much $$$$$?   Thanks!

It's one of these:  http://www.harborfreight.com/12-volt-marine-utility-water-pump-94639.html   I bought it a year or so ago for about $25 (don't you love the HF sales and the 20% coupons), so for occasional non-critical use it should be OK.   The one thing that will kill these vane-type pumps is running them dry, even for a few seconds  -  they don't self-prime!   To avoid this problem, the pump will be mounted below the minimum level of the gray water.  If this cheapo pump works OK, good;  if it doesn't, I've only spent a pittance, then I'll buy a proper marine bilge pump from West Marine or the local yacht parts recycling place.   It's worth a try!

John

[Oonrahnjay]

(snip) It's one of these: (Snip)   

     Thanks.  I don't think that I've had any better luck with HF than anyone else, but I agree, for such a non-critical, low-load use as this, it's worth a try at the price.