SeaLand Holding Toilet Installation

[bikelessman]

Wondering if anyone could assist me with reviewing a SeaLand holding tank toilet installation. I'm not sure if I need a vented loop of not between the toilet and the macerator pump? I am going to run the pump out line up to the deck through a three-way valve, and on the other let from the valve directly to a macerator pump and then to the sea cock. I believe this will provide me with good protection from siphoning, as I will have the sea cock to close, a macerator pump in line and a three-way valve. Is my thinking correct? The toilet, pump and sea cock are below the water line, but the pump out and 3 way-valve are above.

Thanks for your help!

 

[bikelessman]

Forgot to add that the water supply is from the fresh water tank as specified by SeaLand using a 1/2inch tubing. SeaLand indicates there is a check valve in the toilet, should I add another one in the line to make sure that the fresh water supply is not contaminated?

Wondering if anyone could assist me with reviewing a SeaLand holding tank toilet installation. I'm not sure if I need a vented loop or not between the toilet and the macerator pump? I am going to run the pump-out line up to the deck through a three-way valve, and on the other outlet from the 3-way valve directly to a macerator pump and then to the sea cock. I believe this will provide me with good protection from siphoning, as I will have the sea cock to close, a macerator pump in line and a three-way valve. Is my thinking correct? The toilet, pump and sea cock are below the water line, but the pump-out and 3 way-valve are above.

Thanks for your help!

 

[kloudie1]

If you intend to sail with the thru hull after the pump open.. you should have a vented loop between the macerator discharge and the thru-hull. It should be above the waterline when heeled.. If you are religious about closing that thru-hull ANY time you aren't pumping out, it would be OK to go with your schematic. I won't comment on the fresh water check.. just make sure that the literature for the toilet says it can be connected to the potable pressure water system.. they have to have this one worked out if they claim that..

 

[bikelessman]

Thanks for the information. I will be keeping that sea cock and 3 way to the pump closed at all times unless I am 3 miles or more off shore, which will be once in a blue moon as I sail in Cape Cod bay. I will be using the pump out dock most of the time.

Now if I open the sea cock will water instantly rush into the toilet or will the pump act as a check valve? It's a jabsco pump.

also will the jabsco pump self prime from the toilet tank up through the 3 way valve and back down to the thru hull if there is no fluid in that line? It says self priming to 5 ft but does that mean it will pull air until fluid starts flowing through the pump?

Thanks!

If you intend to sail with the thru hull after the pump open.. you should have a vented loop between the macerator discharge and the thru-hull. It should be above the waterline when heeled.. If you are religious about closing that thru-hull ANY time you aren't pumping out, it would be OK to go with your schematic. I won't comment on the fresh water check.. just make sure that the literature for the toilet says it can be connected to the potable pressure water system.. they have to have this one worked out if they claim that..

 

[Benny17441]

Marine toilet connected to fresh water supply? I would not trust a check valve in our bilge and sure would not trust our fresh water supply to one. I would think the connection is to the pressurized side of the plumbing but what happens when leaks develop and air enters the system and the pump electrical circuit is being turned Off as when the boat is left unattended? In boats any motion makes the waterline a moving target. It can range plus or minus from fractions of an inch to a foot or two. They may have a safety design other than a check valve to prevent contamination under adverse conditions but I would make certain before connecting it.

 

[Peggie Hall HeadMistress]

Benny, the toilet in question is a SeaLand 7-11 M28 "Marine Traveler"...see it here on Defender's site (SeaLand's site has been redesigned to make it nearly impossible to get it to anything on it in less than 20 steps):
http://www.defender.com/product.jsp?path=-1|51|2234284|2234292&id=105225

They've been on the market for more than 20 years...designed to be connected to the fresh water plumbing--the connection is the same as the VacuFlush...so trust me, it's totally safe.

Today there are more than a dozen marine toilets that are also designed to be connected to the potable water system...last year Raritan even introduced the first ever MANUAL marine toilet that uses pressurized fresh water--the "Fresh Head"--and it's designed to be connected to the potable water system. They haven't managed to get up on their website yet...here 'tis on the Defender site
http://www.defender.com/product3.jsp?path=-1|51|2234284|2234286&id=2598940, and I'm sure the online store here will have it too. Also available as a "conversion" that let's you re-use your existing bowl.

As for the original question... standards call for a vented loop in any line connected to a below-waterline thru-hull...so I recommend you install one.

I also strongly advise AGAINST any holding tank overboard discharge thru-hull remaining open except when actually in use to dump the tank, whether there's a vented loop in the line or not..

 

[Sailvayu]

No you do not need a vented loop. I do not know what pump you are using but the sealand diaphragm pump has check valves. Even if you do not use that pump and it did siphon back it would only fill the holding tank. And yes you should always close the seacock after a discharge as this could save you from a fine. As for connecting to the fresh water there is no worry about back flow. The fresh water system is under pressure and even if it did backflow for some odd reason it flows into the top rim of the bowl so unless the bowl was completely full and maybe over flowing it would not let sewage into the water system. Do not over complicate things by over thinking it.

 

[Sailvayu]

Peggy what standards call for a vented loop on any thru hull connected below the waterline?

 

[kloudie1]

I wouldn't trust the macerator to hold back the seawater except for the short time between opening the valve and turning on the switch.. The self priming ones are flex impeller pumps and will leak a very little bit normally. If it leaks through, it will fill the holding tank and then try to get out of the toilet to sink the boat. The toilet valve would be the only defense against sinking.he toilet does not have a conventional joker valve but a more reliable "knife gate" type valve. If literature says the macerator is self priming to 5 feet, it will pull air as long as the pump is not more than 5 feet above the level in the tank; this would include any possible high humps in the hose between the pump and tank. You want to have the pump suction as close to the tank bottom level as you can . Like Peggy says, it is much safer to go ahead and install the vented loop in the pump discharge line.

 

[Sailvayu]

As I look back at the drawing I see this is not the typical Vacuflush I see in most boats where the head is under vacuum, but more of a RV set up with the head on the top of the holding tank with gravity feed. The whole kit is below the water line so I will admit the head valve would be a final defense to an overflowing tank. I am not a fan of vented loops as they fail too. So I would not say in this case do not install the vented loop but would say if it were my boat I would not.

 

[bikelessman]

Thanks for the great responses everyone! That is just what I was looking for. I went to look at the toilet again and on the back it has a built in vacuum breaker between the fresh water valve and the bowl inlet. This is also located above the height of the bowl making back flow impossible.

I will make sure my sea cock is always closed as well as the 3 way valve and with the pump being a run dry design I think I will always start the pump a few seconds before I open the sea cook if I use the overboard discharge.

Great help on a great site!

Thanks again!

 

[kloudie1]

Wouldn't start pump before valve is open, BikeLess.. I think that the pump is a rubber impeller pump and if ya run it even for a few seconds with the valve closed, you have a good chance of inverting the blades and killing the impeller; in any case, it will shorten the life considerably. Leakage through that macerator with a good impeller would be a very little bit.. like a cup a minute.. max.. usually less.. so no danger of flooding the tank by opening the valve first...unless the impeller is shot.. even then leakage would be on the order of half gallon a minute.. The pumps are expensive and messy to repair, .. do everything you can to make his life easy !

 

[bikelessman]

Thanks for the advice! I think you're right. The pump should be a stopper in the system and hold most of the flow back. I was also thinking more about the 3 way valve and it dawned on me that I should always keep the valve in the position where the maceration pump is connected to the deck pump out fitting when ever I'm at sea. In addition keep the sea cock closed. Then there is no way water can siphon backwards to the toilet holding tank. Only when I want to pump out or use the maceration discharge should I move the 3 way valve to one of those positions. I'd have to have a complete hose failure and a sea cock failure to flood the boat.

Wouldn't start pump before valve is open, BikeLess.. I think that the pump is a rubber impeller pump and if ya run it even for a few seconds with the valve closed, you have a good chance of inverting the blades and killing the impeller; in any case, it will shorten the life considerably. Leakage through that macerator with a good impeller would be a very little bit.. like a cup a minute.. max.. usually less.. so no danger of flooding the tank by opening the valve first...unless the impeller is shot.. even then leakage would be on the order of half gallon a minute.. The pumps are expensive and messy to repair, .. do everything you can to make his life easy !

 

[Peggie Hall HeadMistress]

Peggy what standards call for a vented loop on any thru hull connected below the waterline?

ABYC