Flushing poo with poo

[amiller]

So despite some good advice, we converted a manual Jabsco head with their electric conversion kit. The old setup worked great, but this is the kids' head and we wanted something easier doe them to flush.

I installed per Jabsco directions (just swap the pump unit and wire it up) and plumbed the flush water to the back of the bowl with the 12" tube provided. Great...except when it flushes some of the waste gets recirculated as rinse water. Gross, but fortunately I'm experimenting with used coffee grounds instead of feces. So it starts to flush by pulling the bowl water down, clean water starts coming in the top, and then in a few seconds coffee starts coming in the top.

Per the instructions, if this happens, you need to run a hose from the flush pump up to the height of the holding tank, and back down to the bowl. I've done this (pictured) but that just delays the arrival of coffee grounds by a few seconds. I presume the material is getting from the dirty pump to the clean pump through the bleed valve?

What do I do next? Some facts:
Saltwater comes from an inlet below the waterline.
Toilet is at/near water line.
Holding tank is above water line, and waste has to go up about 5' to get there.
In the picture, the 1" hose loops up higher than the highest point of the holding tank.

Ps: after all this we are going to take the forum's sage advice and not replace the other manual flush head!

[verb88]

your holding tank is 5 FEET above the toilet?..

oops sorry, posted that before a good look at the picture

[Sea Life]

We have a similar problem, but only when not using holding tank. The head discharge and suction are only 16” apart. So when in direct overboard mode. We flush for a few seconds, wait a few for “cloud” to dissipate, then flush again. If not the suction strainer seems to pick up a few things that are not fun to clean out. Ours are electric raritan if it matters.

If you are using a holding tank when this happens, I have no advice. Internal leak sounds most likely

[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.

[amiller]

Originally Posted by svHyLyte

There should be no connection between the two chambers save the sealed impeller shaft.

There IS this little hose, called something like a bleed line. Could the particles be bypassing this way? I am unable to figure out what it does exactly.

[SV DestinyAscen]

http://jabscotech.com/files/2016/10/...Rev.1docx.docx

Most likely an airlock somewhere or bad joker valve.

[peghall]

I installed per Jabsco directions (just swap the pump unit and wire it up)

It's not quite that simple. The complete installation instructions are in the owners manual here Jabsco 29200 owners manual They are a bit confusing. If you can't sort out the problem, call Jabsco tech support: Paul Campagna is their their toilet guru...his direct line is 978-282-5246.

Peggie

[Sailmonkey]

According to the instructions, if there is recirculating waste you should raise the pump to the level of the highest part of the discharge line.

Edit: looking at the diagram, the bleed hose, when faced with high head pressure from the discharge being led high, will allow waste to flow into the flush pump. The bleed hose is there to prevent an airlock of the poo pump.

I have no idea how you raise the pump.

[amiller]

Originally Posted by peghall

It's not quite that simple. The complete installation instructions are in the owners manual here
Peggie

Thanks Peggy, yes, I did actually follow the instructions in the manual, which includes reference to adding a loop up to the height of the holding tank if poo recirculates. The contact info for the Jabsco guru is much appreciated. I'm wishing I'd followed your previous advice to get a different brand!

Per others' suggestions, I'll make sure there are no bad gaskets, then give Jabsco a call....

[peghall]

Are you sure the toilet is actually recirculating--in which case bowl contents would be coming out the holes in the channel in the rim of the bowl...that what you're seeing isn't waste that isn't making it over the top of the loop, running back down to the toilet? If that's what it is, the joker valve in the discharge fitting should still be closed tightly enough in a brand new toilet allow only very slow seepage. Flushing longer in the dry mode should solve any runback problem...the joker valve may be missing or defective if it's flooding the bowl.

[amiller]

Unfortunately, it is recirculated waste coming in from the little holes at the top. (I'm glad I've only been experimenting with coffee grounds, since the first faulty flush). Contents clear out of the bowl nicely, but then a second later come back in from the top with the rinse water. The joker valve is good (brand new) and once up the discharge line to the holding tank, they stay up.

But it's unsavory to be washing the bowl with recirculated water, and it takes a while before things run clear...

[peghall]

If it's recirculating you've somehow managed to plumb it to do that. Smart move to try it with coffee grounds first...but I suspect YOU suspected something wasn't hooked up right or you wouldn't have thought it necessary. You definitely need to talk to Paul at Jabsco on Monday...preferably from the boat so you can be looking at the toilet when you do.

Peggie

[senormechanico]

Peggie,
I'm glad you said "when you do", rather than when you doo.

Sorry, I couldn't resist.

[ranger58sb]

Originally Posted by amiller

I'm wishing I'd followed your previous advice to get a different brand!

Sounds more like an installation/plumbing problem than a brand problem...

-Chris

[Scorpius]

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.