need info help about toilet

[Ron Hill]

Guys : What Ken is trying to say is Read the Decal on the bottom of the head sink door -- Caution Caution ... turn off the thru hull valve when not in use!!

What I was trying to say is that the inlet fitting on the head pump is not very sturdy!!

A few thoughts

[KeelsonGraham]

Being new to boat ownership, I hadn't realised that yacht plumbing doesn't seem to have heard of non return valves. I accidentally left the macerator sea cock open after using it. The holding tank back filled then overspilled, flooding the bilge. Could have been seriously nasty if I hadn't noticed before leaving the boat.

[KWKloeber]

Being new to boat ownership, I hadn't realised that yacht plumbing doesn't seem to have heard of non return valves. I accidentally left the macerator sea cock open after using it. The holding tank back filled then overspilled, flooding the bilge. Could have been seriously nasty if I hadn't noticed before leaving the boat.

Of course they have heard of them!!  But check valves are generally discouraged except on clean water lines (e.g., supply to the water heater.)
Accumulating poo and paper in a blackwater tank check valve would at some point not seat well and be fairly useless in preventing a backflow.

RTFM and close the thru hulls!!  The same way one can have a failsafe reminder to open the seawater pump valve before starting the engine, one can also make a failsafe reminder to close other thru hulls after using them.

[Noah]

My "fail safe reminder": I keep my engine key sitting on the head countertop next to the sink. That way I grab the key and then open the through hull.

[KeelsonGraham]

Being new to boat ownership, I hadn't realised that yacht plumbing doesn't seem to have heard of non return valves. I accidentally left the macerator sea cock open after using it. The holding tank back filled then overspilled, flooding the bilge. Could have been seriously nasty if I hadn't noticed before leaving the boat.

Of course they have heard of them!!  But check valves are generally discouraged except on clean water lines (e.g., supply to the water heater.)
Accumulating poo and paper in a blackwater tank check valve would at some point not seat well and be fairly useless in preventing a backflow.

RTFM and close the thru hulls!!  The same way one can have a failsafe reminder to open the seawater pump valve before starting the engine, one can also make a failsafe reminder to close other thru hulls after using them.

Sorry KW but there ain't no such thing as failsafe human behaviour. You can have failsafe devices but not failsafe humans.

As far as I'm aware there are no other seacocks on the CAT II that will flood the boat when left open. The others might under abnormal conditions. I'm pretty sure the manual doesn't mention this. It tells you to close the seacock, but doesn't underline the threat.

[KWKloeber]

[edited]

I didn't say or mean to imply failsafe behavior.  I said failsafe reminder (like Noah's -- one cannot start the engine w/o receiving the reminder (some hang the engine key on the thru-hull handle.)) 
If one thereafter chooses to ignore the reminder (human behavior) so be it! 
I often say you can lead (power)boaters to water but you can't make 'em think  LOL!  (tongue-in-cheek -- I'm also a PB.)

If one opens a thru hull ONLY when using the head or macerator I'd suspect that there's some reminder system that would always "tell" the user to IMMEDIATELY close it.  What that might be of course depends on what works best for the individual and I wouldn't even try to conclude that I'd know what method works for someone else -- only what works for me.

But the head intake can also flood the boat.  Kinda likewise, a stuck vent on the cooling seawater vented loop can back-flood the engine cylinders and ruin one's day -- and I know a chap who installed a solenoid valve that shuts off that hose unless the engine is running -- and another who installed a solenoid valve that drains the muffler unless the engine is running.   And of course any thru hull that's left open (hoses will NEVER fail when one's aboard -- only when no one is on the boat.)  I generally close 'em all (my reminder that the sink TH is closed is to put a stopper in the drain.)

[edit]
The manual:
7.  Close valve "B" immediately after emptying the holding tank.

You're right that should carry the same warning as for the head intake valve!

THIS WILL PREVENT WATER FROM FLOODING THE BOAT BECAUSE SEAWATER CAN BACKFLOW THRU THE VALVE, FILL THE HOLDING TANK, AND THEN CAN FILL TOILET AND WILL OVERFLOW THE BOWL.

[AndyBC]

Holger, I don't have anything to add beyond what others have stated but just noticed that your hull # is right after mine!  We're basically family! 

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]

Holger, I don't have anything to add beyond what others have stated but just noticed that your hull # is right after mine!  We're basically family! 

@Andy:  I'll say hello to RUNAWAY from #1218 when I go to Italy in 3 weeks. After all, 30 years ago they stood next to each other in a California hall. 

Holger

[krafty81]

[edited]

I didn't say or mean to imply failsafe behavior.  I said failsafe reminder (like Noah's -- one cannot start the engine w/o receiving the reminder (some hang the engine key on the thru-hull handle.)) 
If one thereafter chooses to ignore the reminder (human behavior) so be it! 
I often say you can lead (power)boaters to water but you can't make 'em think  LOL!  (tongue-in-cheek -- I'm also a PB.)

If one opens a thru hull ONLY when using the head or macerator I'd suspect that there's some reminder system that would always "tell" the user to IMMEDIATELY close it.  What that might be of course depends on what works best for the individual and I wouldn't even try to conclude that I'd know what method works for someone else -- only what works for me.

But the head intake can also flood the boat.  Kinda likewise, a stuck vent on the cooling seawater vented loop can back-flood the engine cylinders and ruin one's day -- and I know a chap who installed a solenoid valve that shuts off that hose unless the engine is running -- and another who installed a solenoid valve that drains the muffler unless the engine is running.   And of course any thru hull that's left open (hoses will NEVER fail when one's aboard -- only when no one is on the boat.)  I generally close 'em all (my reminder that the sink TH is closed is to put a stopper in the drain.)

[edit]
The manual:
7.  Close valve "B" immediately after emptying the holding tank.

You're right that should carry the same warning as for the head intake valve!

THIS WILL PREVENT WATER FROM FLOODING THE BOAT BECAUSE SEAWATER CAN BACKFLOW THRU THE VALVE, FILL THE HOLDING TANK, AND THEN CAN FILL TOILET AND WILL OVERFLOW THE BOWL.

New to my boat and looking for location of valve "b". The manual just has a schematic. Thanks.

[KWKloeber]

New to my boat and looking for location of valve "b". The manual just has a schematic. Thanks.

It would be best to post what you're looking at when asking about something specific (schematic page) so everyone is on the same page.  Literally.