Pete C:

Loop Down - The line does make a loop up to the sink and back down to
the pump and thru-full as an anti-siphon. When you are talking about a
loop down, you mean in addition too, right? E.g. come out of the
shower, loop down, then loop up. If that is what you mean, do I have
to loop down lower than the depth of my shower drain (I cannot, drain
is at lowest point on the boat), or can I get the same if I angle up,
then loop down, then continue up to the sink and back down to the pump
?

Non Return Valve - Thought of that. Other Beneteau owners have tried
the non-return valve, and found that it was useless after some hair
gets in it.




Pete C wrote:
On 14 Dec 2006 09:10:48 -0800, "b393capt"
wrote:

Fred,

It's not possible to do that in my production Beneteau, no room below
the grade of my shower bottom to put such a tank.

In desperation, not having any other ideas to work from or any
recommended designs that don't involve a sump, I am thinking of
replacing the Jabsco shower pump with a Gulper 220, and eliminating the
pump guard.

My hope is that
(1) The Gulper 200 will be more succesful at getting the liquid out
before the suction prime is broken, and less water will flow back into
the shower.
(2) Eliminating the pump guard and shortening the hose 10%, will reduce
the volume of fluid that can reside in the system, and flow back to the
shower. I believe the pump guard can be eliminated because the Gulper
220 materials specifically mention that it isn't needed.

Does anybody see any foley in doing this ?


A washing machine plumbing out kit comes with a non return valve,
maybe this could be used near the shower to prevent back flow. Eg:

http://www.toolstation.com/search.html?searchstr=51805
http://www.toolstation.com/images/library/stock/webbig/51805.jpg

OR,

Use a non return valve or ball valve further up, but loop the hose
from the shower drain down, before it comes up.

As long as the outlet is shut off 100%, and there is a 'U' bend at the
bottom of the hose, there is no way air can get in to break the vacuum
and let the water back down.

I suspect the hose from the shower drain is not looped down in this
way and/or there is a small air leak.

HTH,
Pete.