Why is it coming back?

[nickc]

Peggie,
I have a Hunter 33 with a manual Jabisco toilet. My question is how can you stop you know what from flowing back into the bowl when you are having a brisk sail. I always shut off the seacock but either position on the pump unit seems to allow it back into the bowl particulalry when the holding tank is more than half full. When heeling hard in a seaway this can sometimes cause a distressing mess.
Is something worn or leaking that shouldn't be?
Nick

 

[Ron20324]

The joker valve is the first line of defense to prevent back flow. The second is at the base of the pump, it's a base valve gasket.

 

[Peggie Hall HeadMistress]

Nothing is worn or leaking...

Nor will replacing the joker valve or anything else in the toilet be any more than a temporary band aid...it wont solve the problem.

If it's really backflow, it may be waste left sitting in the line...you aren't flushing long enough in the dry mode to move it all the way to the tank.

But since it seems to mostly happen when the tank is at least half full, I suspect that the real problem is the location of the inlet fitting on the tank...it's outboard (toward the hull) when it needs to be inboard (toward the centerline) so when the tank is more than half full, waste in the tank would run away from it when the boat is heeled. But when the fitting is outboard, waste runs into the head discharge line--and back toward the toilet when the boat is heeled on that tack. I suspect waste also runs out the vent when you're heeled on that tack.

If relocating the fittings is more than you want to do--and I suspect it is, the simplest solution is a loop in the head discharge line....not necessarily a vented loop, just an arch--that's high enough above the tank to prevent tank contents from getting over it. The loop needs to be immediately after the toilet, so that you only have to pump the toilet in dry mode long enough to move bowl contents over the top of it...gravity will get it the rest of the way to the tank.

You said, "either position on the pump unit seems to allow it back into the bowl..."

The wet/dry function on the pump only controls INcoming flush water...it has nothing to do with the toilet discharge.

 

[nick8489]

Thanks Peggy I will now have a go at the loop you suggest.
Just one more point re the wet/dry pump functions. Why do the instructions say you should leave it in the dry bowl position?

 

[alexco38]

The following pic shows the before and after setup. Stuff always back flow during port tack.
The after setup routes the hose to the center line of the boat. Nothing flows back now. I added a connector (from farm supply shop) so I can use a compressor or garden water hose to clear out the hose if any thing get stuck in the 90 degree bend. I rather remove the 90 degree band but the size of the locker won't allow it.

 

[Peggie Hall HeadMistress]

Just one more point re the wet/dry pump functions. Why do the instructions say you should leave it in the dry bowl position?

To prevent sea water from flooding the bowl via the head INTAKE. Although a vented loop will break a siphon--water PULLED through a line--it won't prevent water from being PUSHED through a line, which can happen if the seacock is open when the boat is underway.


Alex, your "before" and "after" have me a bit confused...it appears that you've run the head discharge hose all over the boat to accomplish what a simple loop in the line would do.

 

[Scott B]

If I remember ( but foggy memory) the hose goes into the top of the tank.

Nick, you say that the tank is half full..... is that from the tank indicator or by looking at the tank. My indicator has not worked in 2 years since we got the boat, I pull the hatch in the aft cabin and put a flash light on top of the tank to see the tank level. Perhaps the tank is actually full and backfilling? I've had that problem. Otherwise, pull the pump handle and lube the ring, and check / replace the joker valve.

Leave the switch in dry mode to cut off the water from the thru-hull while sailing.

 

[nickc]

Anything to avoid getting into the stuff

Thanks Scott you do have a point re the tank indicator as mine never reads zero now. After emptying it still shows 1/4 full, so heaven knows what it reads when full. As a matter of interest I had two new tank indicators during the warranty period, I think they were made by some company with a weird name like Snake Industries or something. Anyrate they were pretty useless and only the fuel indicator seems to work properly now.
Thanks for your clarification Peggy.