If the head goes directly to the holding tank and the output of the tank has a Y valve to a deck pumpout or to a manual pump then over board why would an anti-siphon loop be required if the only time the thru hull gets opened is when it is used to pumpout overboard(and 3 miles off shore)? It would seem that with the seacock valve, the Y valve, and the manual pump in one location that it would be a controllable situation with some back pressure but it would be immediately shut off. What am I missing in this simple configuation?
Necessity of a loop
- Thread starter Jim Madden
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Problem's not in the discharge
Jim, If I'm thinking correctly, the anti-siphon loop you're talking about is not in the discharge, but rather in the intake from the thru-hull to the pump, or from the pump to the toilet wet-flush (the line from the pump to the back of the bowl at the top). The purpose is to break any siphon created if the bowl rim outlets end up below the waterline when a flow is initiated. Theoretically you would start a siphon that would self-sustain if you pumped to flush and left the valves open, and that would eventually flood the boat. My 321 has no loop (from the factory), so I never leave the flush lever in the wet-flush position as that seems to stop any potential siphon. I do notice that sometimes the bowl will fill to the outside static water level (about 1/4 up the bowl) if I leave the intake thru-hull open overnight. If the entire bowl were below the waterline, it would flood the boat. Hope that helps! Fair winds, Tim _/)
Jim, If I'm thinking correctly, the anti-siphon loop you're talking about is not in the discharge, but rather in the intake from the thru-hull to the pump, or from the pump to the toilet wet-flush (the line from the pump to the back of the bowl at the top). The purpose is to break any siphon created if the bowl rim outlets end up below the waterline when a flow is initiated. Theoretically you would start a siphon that would self-sustain if you pumped to flush and left the valves open, and that would eventually flood the boat. My 321 has no loop (from the factory), so I never leave the flush lever in the wet-flush position as that seems to stop any potential siphon. I do notice that sometimes the bowl will fill to the outside static water level (about 1/4 up the bowl) if I leave the intake thru-hull open overnight. If the entire bowl were below the waterline, it would flood the boat. Hope that helps! Fair winds, Tim _/)
He's not asking about an intake line loop...
(And if your bowl fills while the toilet is in the dry mode, you're just asking to find it sunk in its slip one day if you don't install a loop in the intake). Jim, what you're missing is twofold: 1)human fallibility--even the slightest possibility that the discharge seacock could be left open...2) your boat will never pass an insurance survey without one because a) humans are fallible....and therefore b) ABYC safety standards require a vented loop in all lines connected to a below-waterline thru-hull. Your boat...your risk. So do what you want to. But in my experience, it's a lot harder to get into trouble by erring on the side of caution than it is take the easy way out and hope for the best...'cuz Murphy was an optimist!
(And if your bowl fills while the toilet is in the dry mode, you're just asking to find it sunk in its slip one day if you don't install a loop in the intake). Jim, what you're missing is twofold: 1)human fallibility--even the slightest possibility that the discharge seacock could be left open...2) your boat will never pass an insurance survey without one because a) humans are fallible....and therefore b) ABYC safety standards require a vented loop in all lines connected to a below-waterline thru-hull. Your boat...your risk. So do what you want to. But in my experience, it's a lot harder to get into trouble by erring on the side of caution than it is take the easy way out and hope for the best...'cuz Murphy was an optimist!
It's the Intake
I have the same setup & expierence as Tim on my C27. Just make sure you shut the seacock if your going to be heeling over, because the water will rise to the water level.
I have the same setup & expierence as Tim on my C27. Just make sure you shut the seacock if your going to be heeling over, because the water will rise to the water level.
My intake line is "T" w/ sink drain
Peggy - My intake line is T-ed with the same sea-cock as the sink drain. It's nice because sometimes I don't even bother opening the seacock and allow the fresh sink water to get pulled into the head. At the end of the weekend it allows me to easily flush the intake line with fresh water. My bowl is below the waterline - I don't have a vented loop. My question is: where should I install the loop? Off the T-ed line that goes to the head? Does the sink drain offer any venting of that line?
Peggy - My intake line is T-ed with the same sea-cock as the sink drain. It's nice because sometimes I don't even bother opening the seacock and allow the fresh sink water to get pulled into the head. At the end of the weekend it allows me to easily flush the intake line with fresh water. My bowl is below the waterline - I don't have a vented loop. My question is: where should I install the loop? Off the T-ed line that goes to the head? Does the sink drain offer any venting of that line?
I've recommended plumbing it that way for years
If the toilet bowl or any part of it is at or below the waterline, yes--you DO need a vented loop in the intake. It has to go between the pump and the bowl--to replace the short piece of hose coming off the top of the pump to inlet fitting on the back of the bowl...if you put it in the intake line, it prevents the pump from priming. In fact, if you don't plug the sink while flushing with sea water, I'd be surprised if you CAN bring in any flush water.
If the toilet bowl or any part of it is at or below the waterline, yes--you DO need a vented loop in the intake. It has to go between the pump and the bowl--to replace the short piece of hose coming off the top of the pump to inlet fitting on the back of the bowl...if you put it in the intake line, it prevents the pump from priming. In fact, if you don't plug the sink while flushing with sea water, I'd be surprised if you CAN bring in any flush water.
Why then?
Peggy, Thanks for your knowledge on the subject. I'm wondering how Beneteau (and likely other mfr's) can build boats to ABYC stds if they are not putting these loops in? My boat is factory stock in the head setup with no loops. Makes me wonder.... Tim
Peggy, Thanks for your knowledge on the subject. I'm wondering how Beneteau (and likely other mfr's) can build boats to ABYC stds if they are not putting these loops in? My boat is factory stock in the head setup with no loops. Makes me wonder.... Tim
Marine Plumbing talk,,,,, Very Interesting.
Jim, Peggie, Rob, cris and Tim, All this plumbing speak is interesting, (Confusing!) Why don't some of you include a diagram of what you are suggesting for this plumbing problem, if for no other reason, for us non-plumber type sailors? By the way, where could a Non-plumber sailor get some guide lines and diagrams for marine plumbing, including marine engine exhause systems? I checked out Peggie's "Related Link" and found the toilet wears but, there was nothing about how to plumb it. Looking for the best way.
Jim, Peggie, Rob, cris and Tim, All this plumbing speak is interesting, (Confusing!) Why don't some of you include a diagram of what you are suggesting for this plumbing problem, if for no other reason, for us non-plumber type sailors? By the way, where could a Non-plumber sailor get some guide lines and diagrams for marine plumbing, including marine engine exhause systems? I checked out Peggie's "Related Link" and found the toilet wears but, there was nothing about how to plumb it. Looking for the best way.
Tim and Hooey...
Good question, Tim. ABYC standards are voluntary...they aren't the same thing as building codes on land. Most boatbuilders are ABYC members, but that doesn't mean they follow all ABYC standards...the standards call for all seacocks to be readily accessible locations, but builders bury 'em in places that some owners never even find! Federal law--which is mandatory--requires all sanitation systems include valves and seacocks that can be secured as described in the while inside the 3-mile limit...but many boat builders use wye fittings instead of y-valves and put tank discharge fittings above the waterline...nothing TO secure. Why are they getting away with it? D'd if I know! However there is no standard or reg that requires a vented loop in a head intake. Toilet mfrs don't include 'em with every toilet 'cuz they're only needed if the toilet is below the waterline...builders aren't gonna spend the money for 'em. They leave it up the owner...too many of whom these days don't know what a vented loop is or what it does (or even where the seacock is, much less ever even think about closing it) till his bowl starts filling up when the toilet is in the dry mode. Hooey...I've never like diagrams 'cuz "one size fits all" diagrams rarely fit ONE installation, much less all. If you go to the link to my book below and take a look at the chapters in Part II, you should have all the information you need to select a toilet and tank, find the best location for it on YOUR boat, and install it. If you're unfamiliar with what things like vented loops and y-valve look like, you'll find photos of 'em in any marine catalog. The West Marine and BOAT/US catalogs also have diagrams of toilet tank installations. As for how to plumb a toilet: When all else fails, read the instructions. Every toilet mfr (every other equipment mfr too)--provides detailed installation, operation and maintenance instructions that include diagrams (including vented loops, btw) with every toilet...and you can download and print most of 'em from their websites. For instance, here's the link to the Jabsco manual toilet instructions: http://www.jabsco.com/prodInfo/overview/29090_MANUAL_TOILET.PDF Same is true for just about every system on a boat. And every system is a learning curve (if you think "plumbing speak" is confusing, try "electrical speak!"). So do some homework...then get back to us with questions about specifc issues you find confusing.
Good question, Tim. ABYC standards are voluntary...they aren't the same thing as building codes on land. Most boatbuilders are ABYC members, but that doesn't mean they follow all ABYC standards...the standards call for all seacocks to be readily accessible locations, but builders bury 'em in places that some owners never even find! Federal law--which is mandatory--requires all sanitation systems include valves and seacocks that can be secured as described in the while inside the 3-mile limit...but many boat builders use wye fittings instead of y-valves and put tank discharge fittings above the waterline...nothing TO secure. Why are they getting away with it? D'd if I know! However there is no standard or reg that requires a vented loop in a head intake. Toilet mfrs don't include 'em with every toilet 'cuz they're only needed if the toilet is below the waterline...builders aren't gonna spend the money for 'em. They leave it up the owner...too many of whom these days don't know what a vented loop is or what it does (or even where the seacock is, much less ever even think about closing it) till his bowl starts filling up when the toilet is in the dry mode. Hooey...I've never like diagrams 'cuz "one size fits all" diagrams rarely fit ONE installation, much less all. If you go to the link to my book below and take a look at the chapters in Part II, you should have all the information you need to select a toilet and tank, find the best location for it on YOUR boat, and install it. If you're unfamiliar with what things like vented loops and y-valve look like, you'll find photos of 'em in any marine catalog. The West Marine and BOAT/US catalogs also have diagrams of toilet tank installations. As for how to plumb a toilet: When all else fails, read the instructions. Every toilet mfr (every other equipment mfr too)--provides detailed installation, operation and maintenance instructions that include diagrams (including vented loops, btw) with every toilet...and you can download and print most of 'em from their websites. For instance, here's the link to the Jabsco manual toilet instructions: http://www.jabsco.com/prodInfo/overview/29090_MANUAL_TOILET.PDF Same is true for just about every system on a boat. And every system is a learning curve (if you think "plumbing speak" is confusing, try "electrical speak!"). So do some homework...then get back to us with questions about specifc issues you find confusing.
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