Check valve in heads inlet anyone?

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Ric

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Jabsco instructions show an optional check valve between sea-cock and the toilet to prevent the pipe from emptying, thereby reducing the need to pump out the air before getting to the water. I am thinking of fitting one as I have a 2.3m pipe and so it can take quite a few strokes of air pumping. However, Is there not a risk that boat movement could force water through the check valve, and eventually flood the toilet?
 
Len Ingalls said:
You may be OK if you install a vented loop :http://www.myboatsgear.com/vented-loops
I'm not a fan of check valves-can hold water in system causing freeze up season,etc.,but I see your problem.
If you install a vented loop.it should keep some water in the line & may be all you need.

Cheers/ Len
Click to expand...

A vented loop in that line will stop the OP from flushing the toilet at all I'm afraid.

The non-return valve should not cause a problem as the vented loop should be in the hose from the pump to the bowl so a syphon cannot start. If the top of your toliet bowl is above the heeled waterline you won't syphon anyway.

Richard
 
RichardS said:
A vented loop in that line will stop the OP from flushing the toilet at all I'm afraid.

The non-return valve should not cause a problem as the vented loop should be in the hose from the pump to the bowl so a syphon cannot start. If the top of your toliet bowl is above the heeled waterline you won't syphon anyway.

Richard
Click to expand...

You are correct.
A non-vented loop may be the answer. That is how mine was plumbed when I got the boat & works fine.
The intake hose comes straight up from seacock to above waterline & back down to head base level & approx. 1m to head inlet.
Been that way since 1984. The discharge hose is plumbed the same. No vents in either. We rarely close those 2 seacocks.
 
Len Ingalls said:
You are correct.
A non-vented loop may be the answer. That is how mine was plumbed when I got the boat & works fine.
The intake hose comes straight up from seacock to above waterline & back down to head base level & approx. 1m to head inlet.
Been that way since 1984. The discharge hose is plumbed the same. No vents in either. We rarely close those 2 seacocks.
Click to expand...

Just don't try that with a toilet mounted at or below the heeled waterline unless you have your wetsuit and flippers or at least wellies, handy.;)
 
Robin said:
Just don't try that with a toilet mounted at or below the heeled waterline unless you have your wetsuit and flippers or at least wellies, handy.;)
Click to expand...

I've often wondered why that doesn't happen Robin. The head seat is close to the Level state waterline with rest of bowl & base below.
The inlet & outlet hoses arch up to top cover of locker just aft of V-berth. Seacocks are in bottom of that same locker & 8-10" below Level waterline. Please see link : https://www.dropbox.com/s/3f0f6mhn2waecmt/Puffin II Layout.jpg?dl=0

Cheers/ Len
 
My question has been answered with non-sequiturs! I am talking about the INLET from sea-cock to toilet. It cannot syphon, because the inlet is below the base of the toilet, and the toilet is above the waterline. So back to my question - if I install a check-valve to prevent the pipe emptying, is there a risk that the movement of the boat could force water up the pipe and eventually overflow the toilet?
 
Ric said:
So back to my question - if I install a check-valve to prevent the pipe emptying, is there a risk that the movement of the boat could force water up the pipe and eventually overflow the toilet?
Click to expand...

If the top of the head bowl ever goes below the water line due to boat movement then I think the answer is yes. but is the answer is that it never will then I don't think so.
 
Ric said:
My question has been answered with non-sequiturs! I am talking about the INLET from sea-cock to toilet. It cannot syphon, because the inlet is below the base of the toilet, and the toilet is above the waterline. So back to my question - if I install a check-valve to prevent the pipe emptying, is there a risk that the movement of the boat could force water up the pipe and eventually overflow the toilet?
Click to expand...

If you place a check valve in a pipe,& jerk that pipe back(sea motion of vessel) & forth,with one end in a liquid(seacock) & the other end open(leaky head),you have built a common siphon pump. Logical?

Cheers/ Len
 
Len Ingalls said:
I've often wondered why that doesn't happen Robin. The head seat is close to the Level state waterline with rest of bowl & base below.
The inlet & outlet hoses arch up to top cover of locker just aft of V-berth. Seacocks are in bottom of that same locker & 8-10" below Level waterline. Please see link : https://www.dropbox.com/s/3f0f6mhn2waecmt/Puffin II Layout.jpg?dl=0

Cheers/ Len
Click to expand...

WE had one that was at waterline level and it wa fine most of the time. The previous owner had added an inline ball valve shut off right by the toilet as a precaution. On the day a visitor forgot to shut that extra valve during a lumpy sail we discovered it could and did syphon over, fortunately only into the shower tray base area so it was easily pumped dry, but it made the point. I don't think our current one would either but our local USA head guru fitted a syphon break in the line from pump to bowl when he installed our new Jabsco Twist 'n lock toilet. Previously there was a basic, boatbuilder installed, manual Jabsco, later adapted by the original owner for electric operation, and which leaked from the electric conversion on our purchase survey. Originally it had no syphon break just a high loop, so it had gone many years perhaps with no problem but on a re-install going back to a manual toilet it made sense to do the job properly and as per Jabsco's instructions.
 
Ric said:
My question has been answered with non-sequiturs! I am talking about the INLET from sea-cock to toilet. It cannot syphon, because the inlet is below the base of the toilet, and the toilet is above the waterline. So back to my question - if I install a check-valve to prevent the pipe emptying, is there a risk that the movement of the boat could force water up the pipe and eventually overflow the toilet?
Click to expand...

Nope. Not non-sequiters. We all know which pipe you are talking about. The position of your inlet is irrelevant. All that matters is whether the top of the toliet bowl is above or below the waterline including when the boat is heeled ..... and you did not mention that previously so I covered the point in #3.

If the top of your toilet bowl is above the waterline at all times, then the chances of a non-return valve pumping water to a point above the water line are negligible.

Richard
 
Robin said:
WE had one that was at waterline level and it wa fine most of the time. The previous owner had added an inline ball valve shut off right by the toilet as a precaution. On the day a visitor forgot to shut that extra valve during a lumpy sail we discovered it could and did syphon over, fortunately only into the shower tray base area so it was easily pumped dry, but it made the point. I don't think our current one would either but our local USA head guru fitted a syphon break in the line from pump to bowl when he installed our new Jabsco Twist 'n lock toilet. Previously there was a basic, boatbuilder installed, manual Jabsco, later adapted by the original owner for electric operation, and which leaked from the electric conversion on our purchase survey. Originally it had no syphon break just a high loop, so it had gone many years perhaps with no problem but on a re-install going back to a manual toilet it made sense to do the job properly and as per Jabsco's instructions.
Click to expand...

Thanks for the info.Makes sense that it could happen if the Raritan PHII open/close knob was accidently left open. Will add to to-do list
Cheers/Len
 
We had a large loop from the water inlet to to the toilet inlet and had no problems at all, I don't see the need to fit a check valve the joker valve stops water coming in unless it has a build up of calcium. It is in fact a choker valve but that was patented so Jabsco couldn't use it.
 
KellysEye said:
We had a large loop from the water inlet to to the toilet inlet and had no problems at all, I don't see the need to fit a check valve the joker valve stops water coming in unless it has a build up of calcium. It is in fact a choker valve but that was patented so Jabsco couldn't use it.
Click to expand...

The joker valve is in the output circuit and this thread is about the input (seawater) pipework, I'm afraid, so no relevance. :)

Richard
 
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