The Joker: nemesis of Batman, and... you?
Does this rubber invention actually work? I've replaced ours and the water still won't stay down. There is no back pressure on the pump and 80% of the time, the urine backs up into the bowl. I've asked some other boat owners and they have the same problem. I think this rubber gadget would do its job if the pipe was vertical with sufficient water weight on the back side allowing the opening to close completely. Anyone have any comments on this? I even called the manufacturer. He said rotate the valve 90 degrees. I tried that and got the same results. I think he was pulling my leg. Would adding some bleach soften the rubber allowing it to close easier?
From casual observation, by the late 80's Ericson was installing the Raritan PH2 head in most boats. It seems to be designed/built very well. As for that rubber "back flow preventer"... ours will also allow a little bit of water back into the bowl once in a while. This is due to a minuscule bit of tp catching in it and not allowing the little flapper to fully close. When this happens, several more vigorous flushes of water through and out of the exit piping will cure the problem.
Often it's a simple as someone trying to minimize the amount of flushing to clear out the bowl -- sometimes out of concern about capacity of the holding tank, or just a guest being a bit self conscious about making all that wheezing pumping noise a few feet from the rest of the crew in the cabin. (Sigh... as though there's a shred of real privacy on any boat under 40 feet anyway.
)
If you boat in an area with lots of seaweed being sucked into the bowl during pumping, a little piece of weed would cause the same problem on the outflow side.
Some boaters have put a longer raised loop in that exit hose with a vented loop at the top. That way very little water can ever drain back into the bowl even if the joker is not working well. Of course then you have an additional place for "stuff" to clog a small valve and cause other problems.
Note that the waste hose to the holding tank or overboard valve needs to have zero waste inside it after you have finished all of your ablutions. If you actually have waste routinely backing up into the toilet, a review of the head piping scheme would be in order as well. (IMHO)
Back a few years, when I reformatted out whole head setup, I put in a new tank with all top-mounted gozinta's and gozouta's with dip tubes for the exits. This lets the entry hose always be free of waste after a few pumps to clear it out.
In general, if you have a good quality toilet and a new joker valve, it might be good to have a quick review of "proper flushing procedure" with the crew.
Happy Flushing,
Loren