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davejean 12-08-2004 05:17 AM

Holding tank location
Hello, I''m wondering if there is any problem with installing a holding tank about two feet higher then the head itself? I realize it is putting weight up high, but aside from that fact is there any common problems with the pump pushing the weight upward? and any problems with the tank leaking back downward? Thanks

e31 12-08-2004 06:46 AM

Holding tank location
Your toilet should be pumping into the TOP of the holding tank. and your holding tank discharge line should run out of the bottom fitting to a deck pumpout or overboard discharge. The only downward pressure would be moving the slug of waste from the toilet to the inlet of the tank. Once in the tank, it would not go back in the hose unless grossly overfilled.

If it were me, I would ensure that clean water was pumped in the hose section after toilet use I would not count on the joker valve holding back a slug of sewage that would continually try top get back in the toilet.

sstonecliffe 09-18-2006 07:39 PM

Holding Tank higher than toilet
Problems with doing this:
1. Pressure is greater than the pump is designed for to get water uphill. The packing around the piston wears out quickly and leaks, getting your hand wet as you pump with sewage and/or outside water.
2. Sewage will sit in the hose unless you pump a great deal of water through the system to clear the sewage, at least 20 strokes. Stinky smells develop.

We have this situation in our forward head. We like the fact that it empties by gravity when out in the ocean. But our Wilcox-Critendon head isn't strong enough to handle the situation. Maybe an electric toilet would be the answer. Holding tank would fill up pretty fast, however. We're still struggling with the odors, continuing to replace hosing, but the above problems remain.

sailingdog 09-21-2006 10:19 PM

Of course, you could do this with a Lavac head, and by properly mounting the pump, you can probably avoid having to pump a lot of excess water to clear the lines.

awayocean 09-22-2006 01:59 AM

Jeanneau 40,Beneteau 361..................are like this,no problems.

groundhog 09-23-2006 12:59 AM

Have you heard of the Kiss system?
I think the holding tank is above the water line and the tank exit and point where the honey-dipper pipe bottoms out is below the tank. Thus, the tank is totally empty when evacuated. Not sure how they handle the pipe from the pump to the input of the holding tank. But that is the advantage of a high tank.... it is totally empty when cleaned out and therefore reduced breeding of smells.

Maybe the ideal is a tank somewhat below the head/pump, but above the waterline?


SmartCaptain 09-23-2006 04:31 AM

Hi davejean,
I have had occasional problems with the "joker" valve in a Jabsco head allowing waste from the waste exit line flow back into the head. (not a lot of volume, but it creates a stink) The waste is coming from the vent loop which, on my boat, goes up about 2.5' above the level of the joker valve. I believe that an entire tank of waste above the head creates the potential for a disaster, as a failure of the joker valve would allow the entire contents of the tank to empty back into the head... ugh!!

Hope this helps,

sailingdog 09-23-2006 08:15 AM


That isn't necessarily a risk, if the tank installation is properly designed.

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