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Peggie Hall

wrote:
Peggie

The head on our boat is a 3 year old Wilcox Headmate. Should there be
any recirculation of the bowl contents happening when one flushes this
head? Either I have just noticed it or the recirculation is getting
worse.

Unless you're seeing waste coming out of the rim of the bowl (which I
don't THINK is happening), your toilet isn't recirculating, bowl
contents are backing up.

The most likely cause is a blocked tank vent that's pressurized your
holding tank...creating backpressure that's forcing waste back into the
bowl. One way to find out: open the deck pumpout fitting. Do it very
carefully, with a hose at the ready, and hang onto the cap...'cuz if the
tank is pressurized, there'll be an eruption. However, no eruption
doesn't guarantee that the vent isn't blocked...'cuz if the toilet
hasn't been used in a while, the pressure can dissipate through the toilet.

Tank vents 101:
All tank vents--fuel, water and waste--have two main functions: to
provide an escape for air in the tank displaced by incoming waste and to
provide source of air to replace contents as they're removed. If air
can't get out, the tank becomes pressurized, preventing it from being
filled...if no air can get in, the pump will pull a vacuum that prevents
it from pulling contents out. So if your tank vent IS blocked, you won't
be able to pump out the tank either.

99% of tank vent blockages occur in the vent thru-hull and the
connection to the tank--both the vent line fitting and that end of the
hose. Scrape out what you find with a screwdriver blade or anything else
that works...if there's a screen in the thru-hull, knock it out...it's
not serving any useful purpose anyway.

Although a blocked tank vent is the most likely scenario, there are two
other possibilities: a clog in the discharge line (someone flushed
something they shouldn't have) or a buildup of sea water minerals in the
head discharge line that has reduced the diameter enough to create
backpressure when you flush.

So start with the tank vent...and do NOT use the toilet again till
you're sure it's completely open. 'Cuz contining to flush a toilet
against a blocked tank vent can pressurize a tank enough to make it
erupt through the toilet, blow out a fitting or even crack the tank. And
don't try to pump out the tank until you're sure the vent is clear
either...a strong pumpout pulling against a blocked vent can create
enough suction to crack the tank.

--
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/boat_odors/