"K2" wrote in message
oups.com...

Thanks for your response, but the vented loop is not for "intake".
Intake is supplied via 1" hose from a sea chest. As stated, output is
from toilet to vented loop to Y valve directing to either holding tank
or thru hull. I am trying to add a macerator pump from the holding
tank overboard. My question concerned where & how to dicect the
macerator pump 1" discharge.


Why in the world would you wish to macerate as you pumped overboard? The
ocean doesn't care how lumpy the product may be. Maceration doesn't kill
bacteria all it does is grind up the sewage into small pieces.

You should get a West Marine catalog and look at the pictures. They have
a couple illustrations of waste systems. The macerator pump is to be
placed on the head discharge tail piece or close to it. You grind up the
product before it goes overboard or into the holding tank. No vented
loop is required or called for on the discharge side of the head. What
on Earth would be the use of a vented loop on the discharge? In a proper
holding tank installation the product enters at the top of the tank and
the tank is vented so there's your vented loop right there. Putting in
another would be redundant.

Wilbur Hubbard