Toilet Vented Loop Question

[Dockhead]

I recently did a little work on my aft toilet -- a Raritan Sea Era conversion with which I have been quite pleased.

It was installed a couple of years ago by a handy crewman (at sea!). I was shocked, when I got into the plumbing, to see that the sea water supply goes directly to the pump with no vented loop, and with a fragile plastic strainer in the line. The vented loop is between the pump and the toilet bowl.

Looks like a recipe for sinking, but when I looked at the Raritan site: http://www.raritaneng.com/pdf_files/...eaerav0103.pdf -- it seems my handy crewman did it just the way Raritan recommends.

WTF? Shouldn't the vented loop be the very first thing? Makes me glad that I am religious about shutting off the sea cock whenever I'm not on board.

Puzzled.

[Sailmonkey]

If the vented loop is on the suction side of the pump The pump sucks air......bad. The loop is installed just as on the main engine, after te pump and before the discharge.

[Ziggy]

If the vented loop came before the pump, the pump would suck air an it wouldn't work. It belongs where you have it.

Shutting off the seacocks when you're not on board is a good practice in any case.

[Dockhead]

Thanks for all of that. But query -- why any vented loop at all? If you can't have it between the sea and the pump?

It seems all inherently hazardous, and makes me think again about fresh water toilets.

[Sailmonkey]

The loop prevents the water from leaking past the pump and flooding the bowl. If your bowl is above the waterline, then you don't really need the loop, but it doesn't hurt a thing.

[Dockhead]

Originally Posted by Sailmonkey

The loop prevents the water from leaking past the pump and flooding the bowl. If your bowl is above the waterline, then you don't really need the loop, but it doesn't hurt a thing.

Thanks -- starting to get it, slowly.

My bowl is below the waterline -- just.

I'm starting to desire a solenoid sea cock which will open just at the moment when water is needed for flushing.

I am very afraid of flooding. Is it irrational? Somehow I don't think so.

[Sailmonkey]

Just think, you've got an engine, probably below the waterline, that is protected by the same sort of vented loop as your head.

[banjoship]

Originally Posted by Dockhead

Thanks -- starting to get it, slowly.

My bowl is below the waterline -- just.

I'm starting to desire a solenoid sea cock which will open just at the moment when water is needed for flushing.

I am very afraid of flooding. Is it irrational? Somehow I don't think so.

Jabsco have a solenoid activated siphon breaker on their electric heads. When the head is flushed the breaker closes, preventing the pump sucking air. You can buy it separately.
Lee

[Dockhead]

Originally Posted by banjoship

Jabsco have a solenoid activated siphon breaker on their electric heads. When the head is flushed the breaker closes, preventing the pump sucking air. You can buy it separately.
Lee

Thanks! Hot tip

[HopCar]

"I am very afraid of flooding. Is it irrational?"
Maybe a little irrational, but that fear is not uncommon.
The only thing in your setup that might cause me concern is the "fragile plastic strainer". You might want to go to a real sea strainer like a Groco ARG.
Groco Raw Water Strainers ARG500-ARG2000

Are the hoses good quality?
Are the hose clamps in good shape?
Do you have a real flanged seacock?
If the answers are yes, you're in pretty good shape.

[Dockhead]

Originally Posted by HopCar

"I am very afraid of flooding. Is it irrational?"
Maybe a little irrational, but that fear is not uncommon.
The only thing in your setup that might cause me concern is the "fragile plastic strainer". You might want to go to a real sea strainer like a Groco ARG.
Groco Raw Water Strainers ARG500-ARG2000

Are the hoses good quality?
Are the hose clamps in good shape?
Do you have a real flanged seacock?
If the answers are yes, you're in pretty good shape.

I have a bronze skin fitting and screwed-on bronze ball valve sea cock as is used in this part of the world. Think this part of it is ok. All real bronze with no brass or anything like that.

Hoses are good. They are over 10 years old and probably about time to change, but still flexible and strong, no cracks, or anything.

Clamps are good stainless Jubilee clips and the hoses are double-clamped.

But the strainer is a flimsy plastic Jabsco job which I don't think belongs below the waterline. This can't be double clamped because the barbs aren't long enough. I think I'll get rid of this. The Groco strainer looks good. How I would like to lead that above the waterline and add a solenoid air vent -- but I doubt I really can afford the time and trouble with all the other things on my list at the moment.

P.S. The toilet in question is one of yours -- and I have been well pleased with it. Thank you.

[NahanniV]

You CAN put a vented loop in the seawater line, but it needs to have a very small orifice so it will not add too much air during flushing.

Easy way to do this is to install the common plastic vented loop pictured below, but pull off the rubber air valve and install a short length of hose with a plug in the end that has been drilled with a small hole.



LAVAC heads have a small orifice that you insert into the top of the seawater intake hose.

Another way to install it is to leave the big vent, but route it to somewhere that you can block it with your finger during flushing.

[HopCar]

Thanks for the feed back. Glad you like the toilet.