Redoing Waste System

[Joe]

What is "counter intuitive" about it. As long as your toilet is above the waterline you don't risk siphoning seawater back into the boat.... but.... if your head is up against the side of the hull, instead of dead center in the boat.. the there's a good chance it drops below the waterline when the boat heels.. so... don't take any chances... especially if you sail with the seacock open. (which means you have crew that use the toilet a lot)

 

[wufibugs]

Having the line higher than the water line made perfect sense given that the head is against the starboard hull. Just seemed odd to have excrement flowing through a vented line. Course, since the vent only allows air in and not anything out . . . . Thanks for setting my mind at ease, Joe.

 

[Ron20324]

...and tell me if it's really true that the discharge from the toilet is supposed to go through the vented loop before it is routed to either the holding tank or overboard. That seems counterintuitive.

You're right... No, it should not be vented. Run the hose above the waterline to make a loop, which should happen when it goes to the tank. When- not if- the vents fail and leak or need to be cleaned/changed... Yuck.

Odds are you'll flush to the tank. If you flush straight overboard, yes, you must close the thruhull when not in use. I have signs on my new boat that tell me that.

If it was my boat, for KISS sake, I'd pump everything to the tank then deal with is as needed from there.

 

[Joe]

The valve can be closed easily, less than a complete turn of the screw, if you see any leakage.. because of its size. Very easy to clean, use a napkin or glove if you're squeamish... but.. it's small price to pay for a little insurance. There's also the problem of making a compact loop with the cumbersome, large sanitary hose.

Besides, the danger is NOT excrement coming from the tank.. it is seawater being sucked back to the bowl. That's the real need for the anti-siphon device if you have a direct discharge option in your system.

 

[wufibugs]

Obviously I'm obsessing over this. Can it be done as in the picture below.
1. I am trying to avoid pumping toilet discharge up 5 feet through the vent [as in picture above.
2. Am I correct that the head vent goes off the head water intake line?

 

[Peggie Hall HeadMistress]

You have the intake vented loop in the wrong place. It needs to be in the line between the pump and the bowl, NOT between the thru-hull and the pump.

You would find it useful to check in the installation instructions for your toilet...the instructions for all of 'em include drawings that show where vented loops and y-valves etc belong. If you don't have the instructions for your toilet you can download them from the mfr's website.

That said, some of their websites have become more trouble than they're worth to try to navigate...if you can't find 'em, email me (EMAIL, not pm please!) and I'll send 'em to you.

 

[wufibugs]

Thanks, Peggy for straightening me out on putting 2nd vent between the bowl and the pump.

I did find the installation instructions from Raritan. It too shows the head discharge going up through the vented loop. Do you think I have to do that or can I just put the vented loop in the line as I have it pictured? It would be a lot easier to plumb that way for a variety of reasons.

 

[Peggie Hall HeadMistress]

That depends on how much time you spend cruising in open water beyond the "3 mile limit" where you'll be flushing directly overboard. If more than 50% of the time, you'll need a vented loop in the head discharge line. But if you'll always be flushing into the tank, you won't need one.

However, depending on the distance from your toilet to the tank or whether the run to your tank will be uphill, a loop--not necessarily vented--could be a good idea, 'cuz a short uphill run over the top of the loop will cut down on the amount of pumping and flush water needed to move bowl contents to the tank.

There are also other plumbing considerations, the vent line size and distance is one. If you'd like to brainstorm a bit, send me an email.

 

[wufibugs]

Peggy, I definitely will be installing 2 vented loops, one between the head pump and head [3/4"], and the other on the head discharge line. I am pretty much using 1 1/4" lines.

My question is this: All the schematics of waste systems show the head discharge lines running up THROUGH the vented loop and then down to the diverter valve. I want to run my head discharge line to the diverter valve with the vented loop going off that line, as in my drawing on post#25. I can't think of any reason the loop won't work that way, but I'm not sure. Not only will it be easier to run the line, but I don't see any good reason to have the head pump elevate the sewage up 5' to the loop and then down again to the diverter valve.

 

[Peggie Hall HeadMistress]

Got your email, see my reply