"Peggie Hall" wrote in message
...
Gordon Wedman wrote:
Peggie
I'm involved in pretty much the same project as K2 and would appreciate
some clarification on a couple of your points.

You say "Put the loop as close to the thru-hull as possible ". Not sure
what you mean here. My vented loop is about 1 foot higher than the thru
hull. Wouldn't this lessen the chance of water being forced back into
the toilet?

"As close to the thru-hull as possible" doesn't have anything to do with
the height of the loop, only with how far upstream from the thru-hull to
put the loop. Obviously, how far upstream depends upon how much height is
available...hence "...as close as possible..."

You also say "tee the line from the macerator into the head discharge
line as close as possible to the
inboard side of the loop". This is the line from the y-valve to the
vented loop, correct?

No...the vented loop needs to be on the outboard side of the macerator.

So when the Y-valve is set to run sewage to the holding tank the toilet
is shut off from the thru hull and you don't need to worry about the
macerator pumping back into the toilet, correct?

Right...but not the way you're envisioning it. The plumbing should be:

toilet to y-valve...one side of y-valve to tank, the other side to vented
loop and thru-hull.

From the tank to a macerator to a tee in the toilet discharge line that's
AFTER the y-valve, but ahead of the vented loop.

Thanks Peggie
You final description is pretty much how I planned it except I had the
macerator tied in at the thru hull, that is, after the vented loop.