On Mon, 14 Dec 2009 11:45:39 -0500, "Flying Pig"
wrote:

A question?

How does one connect to the tank outlet and (in my case) macerator
pump inlet using PVC?



Hi, Richard,

The standard hose outlet fitting takes, of course, 1.5" hose. That hose OD
is exactly the outside diameter of 1.5" pipe.

So, I put a sleeve of hose on the barb fitting. making it exactly match the
end of the barb fitting. I make the connection a tight butt (in our aft
through-hull, it was a slight - maybe 3* - off-line, so I shaved the end of
the pipe, very carefully, to the proper angle to make it a tight butt
fitting).

A standard waste pipe rubber coupling sleeve goes over both. Liberal
application of KY equivalent or teflon grease will allow later moving, as
was the case in my forward head, where I changed out the Y valve, and my aft
head, in which I replaced everything but the bowl - loosen the clamps, slide
the coupling up on the PVC to get it out of the way, and do what you need to
do. Slide it back down to reinstall.

In addition to the standard two hose clamps supplied with the coupling, I
put another right over the butt. That prevents any seepage from getting to
the rest of the coupling. NO possibility of odor transfer. When I took off
my couplings to do my work on both heads, once the other end was out of the
way, I pulled off the coupling and looked inside. Not a mark of seepage on
either one...

Odor-safe or whatever the white hose marketer is, in their website, sells
PVC connectors which are the right size for attaching a hose; even they
recommend PVC where possible. Since, other than in the forward head, I
didn't have any hose points, that was irrelevant. In the forward head,
where I had a small section of hose into the wall, I just took a standard
hardware fitting (screws into the threaded coupling in the PVC) and ground
off the barbs until the 1.5" hose fit it, something I learned from seeing it
on some other application when I got the boat. When I redo that front head
part, I'll unthread the coupling and replace it with straight PVC, making my
bends as needed to match up perfectly with the toilet outlet, using the same
sleeve idea to make the rubber coupling fit. When I rebuild the pump, all
I'll have to do is slide the coupling up the PVC, and remove it, if just
undoing the bolts on the joker holder isn't sufficient.

One other hint, also long-ago discussed here with Peggie, is that we very
aggressively flush with raw water after each use. That helps move any urine
products through the system, minimizing scale formation. We then also dry
pump aggressively to empty the pipe to the anti-siphon. PVC will take
muriatic acid and vinegar with aplomb (get your plomb here, folks, going
fast!), so we do that regularly, too. Of course, we have no proof, but I'd
bet a bunch that we have no scale in our pipes...

HTH

L8R

Skip

Which brings up a question I have always wondered abut.

When flushing a toilet connected directly to the ocean one pumps
flushing water through the system until, it is hoped, all evidence of
one's actions have been eliminated. But how about when one is using a
holding tank. Doesn't all this flushing tend to fill up the tank
rather rapidly

On my own system which has the toilet mounted with the top of the bowl
just above the water line, using the normal anti-siphon "loop", it
takes ten strokes of the pump to pump water completely through the
system. I have no idea what the volume of the pump is but I suspect
that ten strokes is a lot more then the approximately 1 qt. that I see
in the usual holding tank capacity calculations.

Cheers,

Bruce
(bruceinbangkokatgmaildotcom)