Anti-siphon issues

[Trevor]

I decided to replace all the hoses and head in my sanitation system of my 1986 C36. Kinda smelly and I want to get everything shipe-shape for an extended cruise this summer. There are a couple things I've run into that have left me scratching my "head"....1) Did the original plumbing from Catalina not include anti-siphon loops for the intake OR discharge hoses? There is such a loop for the sink/shower drain through-hull, but not for the head? Shouldn't there be a 1/4" anti-siphon loop between the pump handle on the head and the bowl? What about the discharge for the overboard through-hull? There is a "Y" valve set to the holding tank, but there is also hose to the outboard discharge through-hull and a "Y" valve... how can this work without a 1 1/2" anti-syphon loop? I plan on cruising offshore and would like this option. 2) Re: anti-siphon loops, does the discharge one need to be placed downstream of the "Y" valve by the through hull? Can the anti-siphon loop on the intake be before the toilet pump handle or must it be between the handle pump and the bowl? I'd like to set these up as inconspicuous as possible.3) Last one, honest. I bought a new head and "Y" valve by Jabsco. Seems the 1 1/2" fittings are a little small, causing leaks even with double clamps. I've been told to add electrical tape to the fittings to make the tighter fit for the hoses. Shouldn't the fitting be standard? Thanks in advance for any help...TrevorS/V Dunoon, #640Seattle, WA

 

[Peggie Hall/Head Mistress]

Answers...

It's highly doubtful that Catalina installed any vented loops...boatbuilders seldom do But that doesn't mean they shouldn't be there...it depends:If any portion of your toilet bowl is below the waterline, there should be a vented loop in the head intake between the pump and the bowl. (Btw...ALL vented loops should be at least a foot above the waterline at any angle of heel). However, if the toilet is above the waterline, it's not necessary unless you're really paranoid about potential REAL siphons...except in the event a true siphon, water will only rise in the head intake line to the waterline.If the toilet only flushes directly into the tank--no direct overboard capability--I also recommend a loop--not necessarily vented, though--in the head discharge line between the toilet and the tank. Even a half-full tank can overflow back into the intake how and run back toward the toilet when the boat is heeled...a loop in the line that's taller than the waste can cllimb over prevents it from seeping past the joker valve and overflowing the bowl.There should definitely be a vented loop in the head discharge line if the toilet can flush directly overboard. There should be another one in any line that allows you to dump the tank at sea...that one goes betwen the pump and the thru-hull.Forget inconspicuous...at sea safety is your prime concern.As for your Jabsco fittings "mismatch"...they're not 1.5", they're 1". Jabsco is the only mfr who uses 1" discharge fittings on their toilets and macerators. Every other manufacturer uses 1.5". Do NOT try to solve the problem by just adding 1/2" of electrical tapeto 1" hose.... do it right: Buy inline 1" x 1.5" reducers and enough 1" hose to create the proper matchup.And double clamp every connection in the system.

 

[Trevor]

Jabsco

Thanks for the clarification on the vented loops Peggy! I'll take a hard look at what is needed and find a place to add the loops. Re: Jabsco, they are 1.5" fittings, not 1". Ok, not quite 1.5"... I've treated the hose to a good dose from a heat gun and double clamped extremely tight. Seems to hold for now, but I'm going to keep a close eye on the connections to make sure. Of course I will close all through hulls when not aboard.Thanks again for your help!Trevor