[pearson424] Holding Tanks
10 messages
| alan P |
Wed, Mar 8, 2006 at 6:26 AM
|
For those of you who have either installed holding
tanks or already had them when you got the boat, is
there a vented loop on the 1 1/2" output side.
According to everthing I've seen there should be. Mine
does not and I have had no problems that I can see or
smell. For reasons that can be imagined, I just can't
see a big loop in that line, just a straight shot to
the tank (just aft of mast) with a nice downward
pitch.
I do not yet have a thruhull connected (there was one,
but I disconnected it for the time being). If I do
connect a thruhull I am going to add a macerator.
Comments?
Alan
"UNABATED"
#140
__________________________________________________
|
|
|
Lee Thurner
|
Wed, Mar 8, 2006 at 8:16 AM
|
|
Although the holding tank needs a vent line to admit or release
air and
thus keep the tank from pressurizing or collapsing, the
need for a
vented loop on the tank discharge is to keep seawater from
siphoning
back into the boat. If you make other arrangements
to keep this from
happening, you can get by without a vented loop. I
have the holding
tank installed under the sole just aft of the mast step,
with the
discharge on the aft side of the tank leading to a 1 1/2"
tee, one leg
of which leads to the deck pump-out fitting and the other
through a ball
valve to the macerator pump. I have no provision for
direct overboard
discharge from the head; everything goes through the holding
tank. The
macerator pump discharge goes to the overboard discharge
seacock.
There's no vented loop.
To dump the tank (where allowed) I open the seacock and
the ball valve
and run the pump until the tank is empty, then close the
seacock and the
ball valve.
This arrangement has been satisfactory for 12 years.
Lee
Meridian, hull no. 139
|
|
| John Stevenson |
Wed, Mar 8, 2006 at 10:09 AM
|
Alan,
I can think of only one reason for a
vented loop between the head discharge and the tank - if the tank is higher
than the head, in which case nasty stuff could siphon back into the bowl.
I think you are safe and better off to eliminate that extra hose run. You
may want a vented loop between the macerator pump and the seacock. You
could avoid it if you keep the seacock closed except except when pumping
overboard. I used that arrangement on my previous boat. Then I
forgot to close the seacock one day and filled the tank with seawater. It
wasnt a big deal as it only took a few minutes to pump out the seawater
once anchored and I discovered the problem. Of course that could have
gotten me into trouble with the s**t Nazis.
|
|
|
Piescik, Walter
|
Wed, Mar 8, 2006 at 10:20 AM
|
If you do not close the through hull, what prevents the system from
backing up? Is the ball valve you refer to a one-way valve?
|
|
|
Lee Thurner
|
Wed, Mar 8, 2006 at 12:19 PM
|
The ball valve is just a 1 1/2" PVC shut-off valve mounted between the
tank and the macerator pump. It's there chiefly to allow changeout of
the pump without having to drain the tank (Murphy predicts the tank will
be full of **** when the pump decides to pack it in). However, when the
ball valve is closed it also prevents backflow of seawater through the
pump to the tank. If the seacock is left open, the plumbing downstream
of the ball valve, including the macerator pump, stays full of
seawater...not a problem if you trust the hoses, hose clamps, and the
plastic body of the macerator pump. I choose to close both the ball
valve and the seacock when dumping the tank is complete.
Lee
Meridian, hull no. 139
|
|
| alan P |
Wed, Mar 8, 2006 at 7:31 PM
|
Lee,
Did you "T" it to the line going to the deck
fitting or just dead end it?
|
|
|
Lee Thurner
|
Wed, Mar 8, 2006 at 9:59 PM
|
Alan,
Pictures being worth a thousand words, please see attachment.
Lee
Meridian, hull no. 139
|
|
|
alan phillips
|
Thu, Mar 9, 2006 at 6:29 AM
|
Lee, Thanks for the picture. That is
exactly what I want to do. I have a 20-25 gallon tank that is located aft
of the mast. I think it may be a too far forward to put the ball valve
in ( short arms) I do have some ideas.
Thanks again
alan
|
|
|
Piescik, Walter
|
Thu, Mar 9, 2006 at 8:06 AM
|
This
is exactly the arrangement I have, except that I have a "Y"
valve in place of the "T" and ball valve.
It works
great for me. When you are out in open water, you open the seacock,
throw the "Y" valve to the pump out position, and
turn on the macerator. When done, close the seacock right away,
and set the "Y" back to it's normal setting. Then
I take the handle off of the seacock and store it elsewhere,
so that I am in compliance in case I should be boarded and inspected.
|
|
|
