Re: holding tank outflow blockage


--- In, amelliahona <no_reply@...> wrote:

8 April 2007
"Have done more investigation, found out the outflow from the forward
holding tank was blocked"

What was blocked? The vent, the thru hull outlet, the pump-out stand-
The blockage was somewhere between the thru hull outlet and the bottem
of the tapered end of the holding tank

"causing the tank to fill up and cut of vent"

If the thru hull outlet was blocked and the vent was blocked then each
time the toilet was flushed it would pressurize the holding tank and
worsen any joker valve incompetence.
The joker valve was not incompetent. Once the holding tank was full
up, each time the toilet was flushed the overflow leaked out of the
deck vent.

"The seller previously replaced the original holding tank copper intake
tube with PVC tubing"

It is unclear to me which piece of pipe you are talking about, can you
The toilet outflow is connected to the holding tank by means of a hose
which connects the toilet outflow to the inlet pipe of the holding
tank. The holding tank inlet pipe failed at this connection, causing
the leak. The leak soiled the material/fiber lining adjacent to where
the hose traveled.

"He did not remove the original copper tube which remains in the
holding tank, but disconnected from the intake area."

Again I am uncertain how this is possible if it is the piece I am
thinking of.
One of my big concerns is it appears that the holding tank inlet pipe
begins exterior to the holding tank at the inlet pipe connection, then
traverses the vertical length of the holding tank's interior,
extending to the top of the tank where it dumps the black water into
the holding tank. It is this pipe that the seller replaced with PVC
pipe. During the replacement process, he did not remove the original
interior holding tank portion of this pipe, but merely dislodged it so
that it could float freely in the holding tank.

The holding tank on my SM2000 (Hull # 335) is simply a fiberglass
box laminated to the hull with a inlet pipe (from the macerater pump
hose) that dumps into the top of the tank. The outlet is a funnel
shapped portion of the bottom of the box that terminates in the
outlet valve "dump valve" that goes to the thru hull outlet.
Again, my concern is the dislodged original inlet pipe is partially
blocking the funnel shapped portion of the bottom of the box,
interfering with the outflow of black water and promoting blockages.

vent is a couple of holes drilled into the "WC" cap fitting on the
deck. This also acts as the overflow if the tank gets too full. The
black water simply runs down your side deck if overfilled. The
deck WC fitting has a standpipe fitted that goes from the fitting to
near the bottom of the tank so that when pump-out suction is
applied the black water is evacuated from the bottom area of the
tank. The vent works in reverse in this case to allow the tank to
be evacuated. There is not access to the tank for cleaning or

If the thru hull was blocked I would start by treating my holding
tank repeatedly (filled to the top) with a good holding tank
cleaner and exercising the "dump valve", followed by some
vinegar water treatments etc.

Best of luck, Gary
Thanks, Gary. Again, what I'm really concerned about is that the
outflow from the funnel portion of the holding tank is compromised by
the dislodged original inlet pipe, which may have settled in the
funnel shaped area at the bottom of the holding tank. This results in
a partial obstruction to the flow of black water from the box to the
thru hull, and thereby promotes repeated complete blockages. The idea
that I might have to repeatedly have to manually clear repeated
blockages in this area is not something I want to live with.

I'm wondering if anyone else has had this problem, and if there was
any other solution other than cutting an access port into the holding
tank for the purposes of removing the disloged inlet pipe (assuming
the inlet pipe originally vertically transversed the interior of the
holding tank, and then broke off interiorly--if this assumption is
incorrect, then my concerns regarding this are moot). I have also
sent inquires about this situation to Amel, and am waiting for a response.

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