Improve head layout?

[dmksails]

The way my waste system is setup at this time there is over 10-ft of hose between the head and the holding tank! (see pic and diagram). The hose goes horizontally from the head, then goes up to an air release that is well above the waterline, then goes all the way back down to be level again with the bottom of the head, then back up to finally connect to the waste tank. I did not draw in the hose that goes from the selector value to the drain seacock.

I calculated that each flush will take at between 1.5 and 2 gallons - based on hose capacity. That means the tank will only hold at most 26 flushes or about 8 days.

Is there a reason why the hose from the selector value to the holding tank needs to dip all the way back down to the base of the head?

[Hardhead]

I have no accurate idea - but maybe part of the design is to create an air-trap - like the "S" configuration in home plumbing. Whether it needs to dip that far, is a question for someone who actually knows something about this subject. I'd like to learn too.

[tkeithlu]

We have a resident Sewage Queen:" She literally wrote the book on marine heads, and hopefully she will chime in soon. In the meantime, is the hose to the holding tank also the pump out connection? If it is, it goes to the bottom of the tank, and you have as much of a siphon problem with it as with the head itself. Actually, you could siphon your entire holding tank into your living space....

[tkeithlu]

Peggy Hall, that is. She has posted in the last day or so, so help should be on the way.

Good luck with it.

[peghall]

Thank you all for that very warm introduction!


A loop in the toilet discharge line immediately after the toilet that's slightly above the tank can make sense if it's an uphill run to the tank, 'cuz that can make it necessary to flush only long enough to push bowl contents over the top of the loop...gravity can get it the rest of the way. A loop immediately after the toilet can

also be helpful if the tank is further from the toilet than the toilet can push the flush in a reasonable number of flushes.


But there is NO reason why the toilet discharge hose needs to dip below the tank whether there's a loop in the line or not...and you're smart to question it!


Looking at your drawing, it does appear that it's an uphill run to the tank. If so, keep the loop after the toilet--aim the discharge fitting straight up to a loop that's just an inch or two above the top of the tank...and then down directly to the inlet fitting on the tank. If the toilet has a straight discharge fitting, replace it with a 90. You may also need another 90 or 45 tank fitting.


If any of that isn't clear, I'll be glad to sort it out for you.


--Peggie

[Sailcat1]

Do you have any experience with a composting toilet? If the advertisements are true, a Boat is a perfect application, and would save a lot of space, water and power use.

[dmksails]

Ms Peggie - if I understand what you are saying, I could shorten the overall run considerably if I can make the final run from the air breather elbow run downhill to the tank - as in the drawing I just added?

I'll have to relocate the breather and selector value, but it is possible to do.

[peghall]

I think you're confusing the tank vent line with the air valve on the vented loop in the toilet discharge line.


However, the answer to you question is, yes you can definitely shorten the toilet discharge line (line from the toilet to the tank) if you go directly from the vented loop--which is a siphon breaker, not an "air breather"---to the tank.


You don't show a vent line (air breather) on the tank, and the tank does need one. There should be a smaller fitting on--or at--the top of the tank...that's vent fitting. The vent line should go straight to a thru-hull fitting in the hull up near the toe rail.


All of this might be a lot easier to sort out, with answers to all your questions if we could spend about 30 minutes on the phone, and I can be available all day tomorrow (Saturday).
If you'll send me an email (click on my name at the left of this post and select email instead of PM) I'll reply with my phone number. (I don't charge anything to do this).


--Peggie