Re: [Amel Yacht Owners] Head pump

Mike Ondra <mondra@...>

Hi Ian,

Using the high volume flush indeed can improve the character of the backwash
into the bowl, however it also significantly limits the number of flushes
possible when the holding tank is not set to discharger overboard (in port).
I am considering installing a ball valve in the riser pipe just above the
head pump to allow a manual shut off to the backflow problem. Primitive but
should be effective. I would hope there would be a more elegant solution.

Relative to the riser tube inside the holding tank, the swan neck 180 top
would be appropriate to act as a trap to prevent holding tank contents from
sloshing back down the tube. But if the tube was working properly, it would
be full and therefore would not be able to take on more effluent. That
copper riser tube was severely constricted with mineral building in Aletes
as previously reported. I mechanically pried off the buildup with a
combination of screwdriver and hacksaw blade up into the tube as far as they
could reach. My sense was that I could reach fully to the top of the tube
(only with great difficulty and scraping of knuckles) and that it simple
ended near the top of the tank without any elbow or gooseneck. I hope that
is the case because there would be no way to pry off deposits around the
elbow. I would really like to know what the inside plumbing of the holding
tank looks like, and how Amel expects us to be able to maintain any parts
inside it.



[] On Behalf Of Ian Shepherd
Sent: Friday, September 15, 2006 4:19 AM
Subject: Re: [Amel Yacht Owners] Head pump

Hi Mike,

I have always had the same problem with the forward head only. I have
changed the joker valve several times, but it makes little difference. I am
told by Amel that the pump up pipe enters the holding tank via a swan neck,
so there should not be any back flow unless the tank is faulty. The only
way to test it might be to pour some dye into the tank and see if it finds
its way back to the toilet bowl.

I believe that in my case it is probably only what's in the pump up pipe
that back flows. As the forward holding tank is situated higher above the
bowl in the forward head than the aft, it may be the higher head of fluid
that is causing my problem.

The only way that I find to make the situation more pleasant is to make sure
that the toilet is well flushed after use so that only sea water comes back
into the bowl.

Good Luck!

Ian Shepherd SM 414 Crusader

-------Original Message-------

From: Mike Ondra
Date: 9/15/2006 2:04:42 AM
To: amelyachtowners@ <>
Subject: [Amel Yacht Owners] Head pump

We are persistently getting backflow of waste water through the check valves

back into the toilet bowl, enough sometimes to fill the bowl. Besides being
unpleasant at anchor, this can be a mess under sail. I would presume (and
hope) this volume represents the waste water from the riser tube only and is

not siphoning out of the holding tank somehow leaking back through the
tricuspid check valve as well as the flapper valve in the pump assembly.
New valve and flapper seemed to retard the problem for a short time only.

Does anyone know what the riser tube looks like inside the holding tank.
Does it simply extend to near the top of the holding tank with an open end
inches below the top of the tank? Or perhaps there is a 180 deg elbow on

Have other faced this and discovered the problem and solution?

Mike Ondra
Aletes - SM 2000 #240

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