need info help about toilet

[Holger Dieske]

can someone explain the hoses of the Toplette to me?

Picture WC1: the water comes from the left via a seacock under the sink next to the coolant inlet seacock. The seacock is also the waste water from the shower drain.

bottom right is the waste water through the wall to the seacock (can be switched to the holding tank, which I don't use) see also picture WC2.
The sea water goes into the pump at the top right.
Now a seawater hose goes from the pump into the hole behind in the wall and comes out again and goes to the toilet bowl. What is that hose doing behind the wall, why? And how do I get there?

When I have the seacocks of the toilet (inlet and outlet) open, some water flows up out of the drain hole in the shower floor and little by little there is too much water in the toilet bowl.

Can someone explain to me what is wrong and what I should change?

One more question: It's an old Jabsco toilet. I am considering buying a new model from Jansco. Will the mounting holes fit again so that I can simply swap out the toilet 1:1? (possibly with a modified hose routing?)
Holger

EDIT: I can not connect the pictures with the post, biu I hope, i have explained the problem

[Holger Dieske]

Pictures about my questien

[Noah]

There is/should be an anti-syphon valve connecting those two hoses. Its purpose is to stop seawater from back-flowing. If it is like mine, it may be hidden behind the toilet paper cabinet, secured up near the fuel tank. You might be able to see it through the head sink door. The toilet paper cabinet is removable on the MKl, just have to remove wood bungs and unscrew it. You should be able to find all Jabsco model toilet manuals on google.

[Holger Dieske]

... thanks a lot you all!

another question:

there is a shower suction pump. I have it installed under the sink in the toilet.
A hose goes to this from the shower tray (floor).
From this pump a hose goes to the hull culvert. In my case, it is the same outlet from which the flushing water for the toilet is sucked. So 2 hoses on a hull culvert (I think it's a bit stupid, but what the heck)

Now, when the seacock is open, some water always pushes up out of the shower drain hole in the floor. (My PO just put a cork in the hole, but that's not supposed to be my solution in the long run).

My question: is there a non-return valve installed in the shower waste water hose, and if so - where?

Holger

[waughoo]

There is a check valve in the line from the shower drain culvert.  If you follow the line from the shower pump back towards the shower pan you will find it.  Mine was failed when I got my boat and so I put in a new one.  The other great suggestion I have read on here is to put a small strainer AHEAD of the check valve to keep schmutz from fouling the check valve.

[Noah]

Hard to reach area. Many of us have installed a Beckson-style inspection port under the wood sole and some have contemplated even in the shower floor itself, to "better" reach that shower drain hose.

[Ron Hill]

Hogler : Look in the old Mainsheet Tech Notes for my article where I added a "Strainer in the shower drain line" to catch the body "fuzzy wazzys"  -- so they didn't clog the one way shower drain valve!!

A thought

[Holger Dieske]

Ron, I searched these and couldn't find it

Another question:
as Noah wrote, his hose from the toilet hand pump to the toilet bowl goes up through a hole behind the panel (behind the toilet, look my Pic number one) and back through the opening to the toilet bowl via an anti-siphon valve.
That's how it is with me too (although I haven't been able to see exactly how it is behind the wall.
I've looked at a lot of pictures of other C34's and for most of them this connection is just a short piece of hose from the toilet pump to the toilet bowl, i.e. without this anti-siphon valve behind the panel. Otherwise everything seems the same in the pictures.
Why do I (we) need this?

Holger

[crieders]

A bit off topic but I am trying to find an electric head that fits
I looked at the Raritan Sea Era QC but with the bowl properly aligned to fit, the discharge hose would come out in front. Does anyone have a picture of an installation? Thanks

[Dave Spencer]

Holger,
The vented loop (anti-siphon valve) is required when the toilet is at or below the waterline.  If the pump is left in the wrong position after using the head, water can siphon from the sea into the toilet bowl eventually overflowing and flooding, possibly sinking the boat.  Either operator error or a failure in the pump would have to to happen but the vented loop eliminates the chance of drawing sea water into the toilet bowl unless it is deliberately pumped in with the toilet pump.  Many boats don't have a vented loop but it is wise to have one installed, especially where the toilet is located on our C34s. 
Here's a link that may explain it better: https://marinesan.com/y-valves-vented-loops-check-valves-etc/vented-loop-q-a/

[Holger Dieske]

... thx Dave.

Holger

[KeelsonGraham]

Holger,
The vented loop (anti-siphon valve) is required when the toilet is at or below the waterline.  If the pump is left in the wrong position after using the head, water can siphon from the sea into the toilet bowl eventually overflowing and flooding, possibly sinking the boat.  Either operator error or a failure in the pump would have to to happen but the vented loop eliminates the chance of drawing sea water into the toilet bowl unless it is deliberately pumped in with the toilet pump.  Many boats don't have a vented loop but it is wise to have one installed, especially where the toilet is located on our C34s. 
Here's a link that may explain it better: https://marinesan.com/y-valves-vented-loops-check-valves-etc/vented-loop-q-a/

I can vouch for this. It happened to us recently. Came down below to find water slopping around the cabin sole. I'd left the toilet inlet seacock open. Toilet bowl was full of seawater and overflowing.

[Noah]

Cliff-
https://c34.org/bbs/index.php/topic,11272.msg91037.html#msg91037

[Ron Hill]

GUYs : Also be VEVY careful when cleaning or working behind the toilet!!  I was doing something and the inlet water hose + the fitting fitting on the pump assembly (must have been cracked) and came off in my hand with the inlet water hose still attached!!  I had the head inlet water thru hull valve shut off.  If that had happened with the valve open I could have flooded the boat.  The vented loop only protects syphoning between the pump output to the bowel!!   

So "heads up" when you are working around the back of the head!!!

A few thoughts

[KWKloeber]

The answer, of course, is to RTFM.

2. ....... THE VALVE SHOULD BE KEPT
CLOSED WHEN THE HEAD IS NOT IN USE. THIS WILL PREVENT
WATER FROM FLOODING THE BOAT IF THE VALVE IN THE TOILET
PUMP SHOULD FAIL.

If the thru-hull is open only when necessary, OR AT LEAST CLOSED when you leave the boat or are sailing (HEELING,) "an accident" CAN NOT occur. Fact. 

RTFM.