Flushing poo with poo

[Sailshabby]

Maybe it’s the coffee. Decaf? Dark Roast?

[Dave22q]

Sounds like flapper and/or high back pressure from a nearly full tank with a clogged vent. Does your pump handle stay down when you stop? You can eliminate the poop problem by flushing with enough sea water to move the poo past the joker valve. That way what comes back will be clean sea water. Also use extra pumps when you empty the bowl and clear the tank vent hose as needed..

[HopCar]

Originally Posted by Scorpius99eh

I would say the unusually high back pressure from the discharge side (because the holding tank is so much higher than the toilet) is forcing discharge fluid back through either the bleed hose or the internal seals to the clean side.

I agree with this except it can't be getting through the internal seals. If it got past the lower seal it would have to pass through the motor and a slinger to even get to the upper seal. It has to be going through the bypass hose. This is the only connection between the discharge pump and the intake pump. I have to admit I don't understand what the bypass does but I think Scorpius must be correct with it having to do with excessive back pressure.

I'd be tempted to pinch the bypass hose closed and try flushing it. Of course the whole thing might blow up. What fun that would be! Get video for YouTube.

[peghall]

Dave...the toilet is electric...this one:Jabsco 29200_Electric_Conversion ....it doesn't have a pump handle.

You MAY be onto something with a clogged tank vent, but a tank 5' above the toilet would create so much backpressure its unlikely a blocked vent is the culprit...especially since the any pressure IN the tank would have been relieved when he removed the toilet discharge hose to swap out the pumps.

[CaptTom]

Originally Posted by peghall

...especially since the any pressure IN the tank would have been relieved when he removed the toilet discharge hose to swap out the pumps.

I made the mistake of trying to visualize that...

[amiller]

Originally Posted by HopCar

It has to be going through the bypass hose.
I'd be tempted to pinch the bypass hose closed and try flushing it. Of course the whole thing might blow up. What fun that would be! Get video for YouTube.

HopCar, I agree. The holding tank is brand new, the discharge line brand new, the joker valve, brand new.

The system worked great for the 3 days I had the old manual flush pump in place, there is of course no bypass hose in the manual pump.

Vent line is brand new and unobstructed, and the discharge seacock is open because I'm only flushing saltwater and coffee. (On this boat waste goes up into the tank, and then out a discharge line, there is no Y-valve.

Either I installed something incorrectly, or the the high discharge pressure from the ride to the tank makes some of the waste prefer the easy path the bypass hose. With the next batch of coffee grounds I'll clamp off that hose....worst case is an airlocked impeller or maybe a coffee explosion. Fortunately I like coffee.

[allendick]

I had the same issue, but in a setup with direct discharge up through a loop and back to waterline.

I figured the hose is old and maybe back pressure was the problem, and could see that the bleed was an alternate route, but had trouble believing all that crap could come up that tiny bleed. I was even more doubtful after pulling the top and seeing the tiny 1/8" hole the bleed hose leads to.

Nevertheless, I did take an SS wood screw and twist it a turn or two into that hole to block it, put the top on and voila!

Problem solved.

Hope this helps someone. I had put up with this for several years after I bought the boat. Someday, I'll change the hoses.

(Sure).

[Shrew]

Originally Posted by svHyLyte

It sounds to me like the seal between the raw water up-take impeller chamber and the maceration/discharge impeller chamber is shot. There should be no connection between the two chambers save the sealed impeller shaft.

Or simply installed incorrectly. Mine was missing a seal that appeared to be an 'optional' item according the instructions. It was NOT optional.

http://www.cruisersforum.com/forums/...or-185548.html

[allendick]

We may be talking about different units. I'm talking about the 29200-0120 manual to electric conversion. In this design, the two pumps are physically separated vertically by a motor with a shaft out each end and the only possible connection is a small bleed tube of unknown function. My guess is that it is designed to drain the top pump, maybe for winterizing? Dunno.

What I do now know is that if the bottom pump generates pressure due to outlet restriction for any reason and the intake is at all restricted, the intake pump sucks crap up the bleeder. In my case, probably both hoses are less than pristine.

Blocking the bleeder stopped it dead and for the first time in a while the toilet flushes cleanly without recirculating crap.

This puzzled me for a year or two and the solution is so simple, I thought I would share. The only tricky part is not to tear the gasket when lifting the top.