I have a siphon break in the raw water inlet to the head - but it has to be between the pump and the bowl. If you put a siphon break into the line before the pump, you will never be able to get water into the pump.
Imzadi has three destinations for black water coming from the head (yes, it is a plumbers nightmare), and only one has a siphon break. The line from the head to the Lectra-San has to be as horizontal as possible in order to move black water to the device. The output from the Lectra-San goes up vertically before going out the through hull, so there is little chance of a siphon. The line to the top of the small holding tank does not need a break - as Martin said, the air vent for the tank serves that purpose. My overboard discharge does have a siphon break. The joker valve in the pump should keep any black water in whichever discharge line is being used from leaking back into the bowl. Rick Brass Washington, NC From: CnC-List [mailto:cnc-list-boun...@cnc-list.com] On Behalf Of Martin DeYoung Sent: Thursday, July 11, 2013 8:27 PM To: cnc-list@cnc-list.com Subject: Re: Stus-List Introduction and gastric reflux >> I never really understood the loop in the discharge line.<< The vented loop is indeed to prevent a syphon from beginning. I have the vented loops for all hoses that can access raw water in quantities that would create a flooding. (head discharge and engine raw water especially) I have also read of placing a syphon break in the raw water supply for the bowl but do not have one on Calypso's head. We shut off the head water supply when not in use. I have not specifically studied whether a hose that only goes between the head discharge and the top of a holding tank would require a vented loop (air space of a partially full tank would also be a syphon break). I would recommend having the hose routed to avoid standing black water in the hose (run downhill to tank) as standing black water will cause odor to permeate the hose. >> I've never actually done my business on a boat before. << Wow. Having made multiple 20 to 30 day offshore passages and cruised with the family on board I have never considered the option of keeping the head that pristine. I will discuss this with the 7 to 8 Calypso Crew that will be onboard for a 100 mile race late August. Maybe there will be enough wind for everyone to hold it start to finish. <VBG> When well offshore, especially in trade wind conditions (i.e. warm) I have been known to use the "aft" head, the one with a great ocean view. Sitting out in the open air with a roll of TP on a sail tie around my neck it was mostly comfortable but one does worry about the errant flying fish. Martin Calypso 1971 C&C 43 Seattle cid:D1BF9853-22F7-47FB-86F2-4115CE0BAF2F From: CnC-List [mailto:cnc-list-boun...@cnc-list.com] On Behalf Of Stevan Plavsa Sent: Thursday, July 11, 2013 8:29 AM To: cnc-list@cnc-list.com Subject: Re: Stus-List Introduction and gastric reflux I never really understood the loop in the discharge line. If your discharge line feeds the tank on top of the tank, in the middle, how would the contents of the holding tank get back into the hose? I understand not everyone's setup is this way ... and I'm only chiming in because I'm about to plumb mine the way I described, I hope I'm not screwing something up. I don't like the idea of a vented loop in my discharge, complicated .. and potentially gross. As to Peter's problem, my guess is the hose goes up before it goes down again, so there are always contents in the hose. Your joker valve isn't working well so the contents of the hose backwash into the bowl (IMO another argument in favour of ditching the vented loop in the discharge). The fix would be to fix/replace that joker valve and to make sure to pump the contents well clear so that if there is any backwash it's .. cleaner. I've never actually done my business on a boat before so I'm not the best person to be giving this advice, much less redesigning and installing my own system so if I'm off base I'de like to know! Steve Suhana, C&C 32 Toronto On Thu, Jul 11, 2013 at 8:27 AM, dwight veinot <dwightvei...@hfx.eastlink.ca> wrote: Probably caused by siphoning action.do you have a vented loop in the discharge line? Like this one: http://ca.binnacle.com/Plumbing- <http://ca.binnacle.com/Plumbing-&-Pumps-Plumbing-Hardware/c31_264/p2249/FOR ESPAR-1-1/2&%2334-VENTED-LOOP/product_info.html> &-Pumps-Plumbing-Hardware/c31_264/p2249/FORESPAR-1-1/2&%2334-VENTED-LOOP/pro duct_info.html Dwight Veinot C&C 35 MKII, Alianna Head of St. Margaret's Bay, NS
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