I want to put in a Jabsco (Model 2675387) self priming Macerator pump
to empty the holding tank when I’m more than three miles out. Will
typical "Y" valves be tight enough under suction for the pump to draw
from the tank instead of pulling so much air into the line around the
"Y" valve seals that it just cavitates? Some seals work fine under
pressure but leak under suction.


The pump will only have to lift about 15 inches. It says it’s self
priming to 5’ when "wet" but my experience with getting pumps to prime
is that it doesn’t take much air leakage to result in major
frustration.

Any particular "Y" valve I should be looking for to avoid this as well
as minimize the possibility of its being an odor source?

--

Roger Long

Roger:

Combraco bronze y valves are very tight. Other plastic bodied valves I would
wonder about.

David

Roger Long wrote:

I want to put in a Jabsco (Model 2675387) self priming Macerator pump
to empty the holding tank when I’m more than three miles out. Will
typical "Y" valves be tight enough under suction for the pump to draw
from the tank instead of pulling so much air into the line around the
"Y" valve seals that it just cavitates? Some seals work fine under
pressure but leak under suction.

That y'valve shouldn't be under suction, Roger...tank contents should be
being pushed over it. It goes between the pump and the thru-hull.

Any particular "Y" valve I should be looking for to avoid this as well
as minimize the possibility of its being an odor source?

I'd go with a Whale.


--
Peggie
----------
Peggie Hall
Specializing in marine sanitation since 1987
Author "Get Rid of Boat Odors - A Guide To Marine Sanitation Systems and
Other Sources of Aggravation and Odor"
http://shop.sailboatowners.com/books...ku=90&cat=1304

Oh hell...you said y-valve, my brain read vented loop. Sorry...it's been
a long week.

Good quality y-valves don't leak, so you won't have any problem. Again,
go with Whale...avoid Jabsco, they DO leak.


Peggie



Roger Long wrote:

I want to put in a Jabsco (Model 2675387) self priming Macerator pump
to empty the holding tank when I’m more than three miles out. Will
typical "Y" valves be tight enough under suction for the pump to draw
from the tank instead of pulling so much air into the line around the
"Y" valve seals that it just cavitates? Some seals work fine under
pressure but leak under suction.


The pump will only have to lift about 15 inches. It says it’s self
priming to 5’ when "wet" but my experience with getting pumps to prime
is that it doesn’t take much air leakage to result in major
frustration.

Any particular "Y" valve I should be looking for to avoid this as well
as minimize the possibility of its being an odor source?


--
Peggie
----------
Peggie Hall
Specializing in marine sanitation since 1987
Author "Get Rid of Boat Odors - A Guide To Marine Sanitation Systems and
Other Sources of Aggravation and Odor"
http://shop.sailboatowners.com/books...ku=90&cat=1304

But, then the pump out boat and the marina pump out have to pull the
sewage through the pump. The pump out at our marina has enough
trouble lifting the stuff 15 feet at low tide. I don't want to add
the head loss of a pump to it. A self priming pump won't pass stuff
that way anyhow.

Normally, I could turn the pump on to make it easier for the
marina/pump out boat pump but we have a great service here in
Portland. You sign up with the Friends of Casco Bay and the boat
stops and pumps your tank once a week whether you need it or not. I
won't always be there to turn on the pump when they stop by.

--

Roger Long



"Peggie Hall" wrote That y'valve shouldn't be
under suction, Roger...tank contents should be
being pushed over it. It goes between the pump and the thru-hull.

Any particular "Y" valve I should be looking for to avoid this as
well as minimize the possibility of its being an odor source?

I'd go with a Whale.


--
Peggie
----------
Peggie Hall
Specializing in marine sanitation since 1987
Author "Get Rid of Boat Odors - A Guide To Marine Sanitation Systems
and Other Sources of Aggravation and Odor"
http://shop.sailboatowners.com/books...ku=90&cat=1304

Roger Long wrote:

But, then the pump out boat and the marina pump out have to pull the
sewage through the pump. The pump out at our marina has enough
trouble lifting the stuff 15 feet at low tide. I don't want to add
the head loss of a pump to it. A self priming pump won't pass stuff
that way anyhow.

As I said, Roger...my brain burped...it's the vented loop, not the
y-valve, that goes between the pump and the thru-hull. The y-valve, of
course, goes ahead of the pump...there'd be no reason to put it after
the pump.

Sorry for the confusion...
--
Peggie
----------
Peggie Hall
Specializing in marine sanitation since 1987
Author "Get Rid of Boat Odors - A Guide To Marine Sanitation Systems and
Other Sources of Aggravation and Odor"
http://shop.sailboatowners.com/books...ku=90&cat=1304

"Peggie Hall" wrote in message
om...
Roger Long wrote:

But, then the pump out boat and the marina pump out have to pull the
sewage through the pump. The pump out at our marina has enough trouble
lifting the stuff 15 feet at low tide. I don't want to add the head loss
of a pump to it. A self priming pump won't pass stuff that way anyhow.

As I said, Roger...my brain burped...

snip --

Peggie
----------
Peggie Hall
Specializing in marine sanitation since 1987
Author "Get Rid of Boat Odors - A Guide To Marine Sanitation Systems and
Other Sources of Aggravation and Odor"
http://shop.sailboatowners.com/books...ku=90&cat=1304


You are lucky Peggie because mine only farts and never burps. ;-)

Thanks.

I actually plan to skip the vented loop in this case. Because the
USCG requires these pump outs to be secured against unintentional use,
I'm going to remove the lever from the seacock. I'm also going to put
the switch for the pump right by the tank so I can watch what's going
on (like if the vent plugs and the pump starts to collapse the tank).
This is for occasional use. I may never use it but I like the boat to
be self sufficient. The idea of being dependent on shore support for
something as basic as getting the sewage out doesn't sit well with me.

A "Y" valve may not be the best solution here either. I may just put
a ball valve in the deck pump out line. The seacock will shut off the
other side of the system.

No, that's a bad idea. Sewage would sit in the overboard line, maybe
forever. With the "Y" valve, I would pump out, then let seawater back
flow briefly to clear the overboard line (everything is below the
W.L.). Then shutting off the seacock and switching the "Y" would
leave mostly seawater in the discharge line and the boat ready for
normal pump out.


--

Roger Long

My waste tank is purged to the sea or, with an external hose connected,
to the Wall Mart plaza storm sewer like RVers do it, or an external
tank, like my porta pottie from the truck, using air pressure. We
don't need no steenkin' macerator pump, nor no 'nuther pump neither,
except the 12vdc tire pump, which pressurizes the system enough (1 or 2
lbs overpressure) to blow the "ballast" out the marine discharge. I use
a plastic ball valve as a sea cock, and it doesn't leak. Nor does the
joker valve, even with pressure on.

The only time I open the cheap plastic ball valve / sea cock / port /
sea valve is when emptying the holding tank. The only valve, aside
from air vent valves in the system, is the one sea cock ball valve.
There is a tee between the head, through hull / sea cock, and holding
tank pipe.

Two minutes of pumping air into the tank with the air vents closed and
the sea cock open and it all goes out. Then, it farts to let me know
it's done.

Terry K

Hmm, I like this idea. Running that airline down into the bottom of
the tank with lots of holes would also let you aerate stuff if you
were in a no discharge zone. A 12 V air pump is 1/10 the cost.

What kind of tank do you have? I would have to pump against the head
pressure of the tank being below the waterline so would need 2 - 3 psi
which is a fair amount for a plastic tank. I would sure hate to bust
something.

--

Roger Long



"Terry K" wrote in message
oups.com...
My waste tank is purged to the sea or, with an external hose
connected,
to the Wall Mart plaza storm sewer like RVers do it, or an external
tank, like my porta pottie from the truck, using air pressure. We
don't need no steenkin' macerator pump, nor no 'nuther pump neither,
except the 12vdc tire pump, which pressurizes the system enough (1
or 2
lbs overpressure) to blow the "ballast" out the marine discharge. I
use
a plastic ball valve as a sea cock, and it doesn't leak. Nor does
the
joker valve, even with pressure on.

The only time I open the cheap plastic ball valve / sea cock / port
/
sea valve is when emptying the holding tank. The only valve, aside
from air vent valves in the system, is the one sea cock ball valve.
There is a tee between the head, through hull / sea cock, and
holding
tank pipe.

Two minutes of pumping air into the tank with the air vents closed
and
the sea cock open and it all goes out. Then, it farts to let me know
it's done.

Terry K