Waste System - How does it actually work?

[rpwillia]

So I replaced my joker valve on my boat and two complete head pumps on a friends boat. While doing this I go to thinking and can't wrap my head around it. When you flush the toiled, the waste (water and stuff) goes out the pump and into the hose and then usually up before running to the holding tank. How is it the water does not go back down to where the pump is as there is air in the line?

 

[justsomeguy]

How is it the water does not go back down to where the pump is as there is air in the line?

I think that's a big part of the joker valve's function.
Maybe the only one.

 

[Peggie Hall HeadMistress]

The joker valve does NOT prevent water from running back downhill to the pump, it just keeps what wasn't pumped long enough to make it into the tank out out of the bowl. And that's not the joker valve's only function, that's its LEAST important function in a manual toilet.

To answer Ray's question...you just need to pump enough times in the DRY mode to move the flush over the top of a loop (if there is one), then let gravity get it the rest of the way. Follow enough enough WET pumps to rinse the hose behind the flush, the switch to dry again to finish the job. If you learn to use the dry mode to more than just get the last of the water in the bowl, you'll not only reduce the amount of water that runs back downhill, you can also increase the number of flushes the tank can hold by up to 50%. How well this works also depends on whether the person who laid out the toilet discharge plumbing route had even the slightest idea of how to do it correctly...most boat builders don't.

--Peggie

 

[justsomeguy]

And that's not the joker valve's only function, that's its LEAST important function in a manual toilet.

What else does it do?

 

[Peggie Hall HeadMistress]

You'd know if you had my book...it's full of info you prob'ly have no idea you don't know, but should.

This is an excerpt from chapter "Joker Valve 101:"
The joker valve is THE single most important replaceable part in a manual toilet. Here's why:
On the upstroke of the piston, a vacuum is created in the area beneath the piston. This causes the joker valve to close tightly, and the flapper valve beneath the pump to open, allowing some of the contents of the toilet bowl to be drawn into the bottom half of the pump. Then, on the down stroke of the piston, the flapper valve is slammed shut, and the effluent is forced out of the bottom of the pump, through the joker valve, and off down the line. But when the joker valve becomes worn and/or there's a buildup of sea water minerals on it, it can no longer seal tightly on the upstroke of the piston so less and less vacuum is created, requiring more and more pumping to move bowl contents.

You prob'ly won't notice the loss of efficiency at first because it's so gradual. But I guarantee you that if it's been two years or longer since you replaced the joker valve, you need to pump the toilet at least 50% more times to move the bowl contents to the tank or all the way out the thru-hull....IF they're getting there at all any more.

And THAT's why the joker valve should replaced at least annually!

-Peggie

 

[nightowle]

Yes, get Peggy's book. It's worth it, for sure!

 

[Paul Mermelstein]

My boat has holding tanks mounted vertically next to and above the toilet. The waste must be pumped upwards about 3-4 feet to the top of the tank. So, based on Peggy's book (which is great) and common sense, we flush first with some water and then the dry mode about 20 rapid strokes after the bowl is empty. This pushes air and waste up the hose and gets it fairly empty. I also use a Raritan duckbill "joker" on the Jabsco head; works great and lasts two years or longer. This combination results in zero waste leaking back into the bowl.

 

[dLj]

Yes, get Peggy's book. It's worth it, for sure!

+1

dj

 

[justsomeguy]

Golly!