Anti-Siphon ... Dumb Question!!!

Don S/V ILLusion · Dec 10, 2014

To preclude the possibility of siphoning water back. They require periodic maintenance along with lots of other stuff. When did you last open and clean the valve?

Stu Jackson · Dec 10, 2014

Third one in week:

http://forums.catalina.sailboatowners.com/showthread.php?p=1168402&highlight=vented

Bill Roosa · Dec 10, 2014

The motor is below the water line. If you start pumping water into the boat and the impeller has a couple of vanes off, when you stop the water will keep running into the boat around the busted impeller and into the exhaust manifold flooding the engine. If it has to go up and over its own water level due to the anti-siphon loop then the water will stop IF there is a vacuum break valve at the top to let the water above the water line (and at lower than atmospheric pressure at that point) seek its own level. Breaks the circuit so no flooding.
Not much chance the impeller will both have enough vanes broken and stop in just the right location to allow water to flow when stopped but ......

seadaddler · Dec 10, 2014

Funny

Mine doing same thing and some reason it stopped and have not
had a chance to take apart and see what 's up and maybe just
need cleaning from salt water.
Maybe will take apart tomorrow.
Nick

seadaddler · Dec 11, 2014

vented loop

Well inspected my engine vented loop and you can see pretty clean for sure
and mine has been used always in salt water from day one 2007.
Last time I ran the engine and not so much water coming out and will keep a eye on things for now on and maybe even take off my mixing elbo and check that to see if it is loaded with gunk and the hoses do come from the mixing elbo
to the heat exchanger.
Nick

seadaddler · Dec 11, 2014

Vented loop

Sounds like a good idea with the bottle and was thinking next time
I run engine I will put hose in bottle for sure and my hose goes into under the engine into closed engine pan.
I did not see any water coming out last time I ran engine and only noticed
water under engine when changing impeller and cleaning up my raw water
pump and needed to clean and paint bracket for the pump and than when ran the engine saw the water.
My step son is visiting us and so no boat for while maybe when I return
New Years,have happy Xmas and new Year and if you go to Noel's say
hello to gang for us and really will miss all the holiday parties in PG this year.
Nick

Don S/V ILLusion · Dec 11, 2014

Nodak7 said:
Don, our boat was in fresh water up until last year and I never have done any maintenance on it. It sounds like I can just remove the top and check it for salt or debris. Is it normal for them to "spit" out water occasionally or should it be dry?

If functioning properly, you shouldn't have any water coming out.

On every boat we've ever owned, one of the first things I did was trash the plastic valve and replace it with a bronze Vetus loop.

Heat and plastic don't like each other.

FredV · Dec 20, 2014

Same thing happening on my boat - the bronze (not Vetus) anti-syphon device spits water contiuously when the engine is running. According to the product manual for a Vetus device, "... a small quantity of water will flow out of the hull outlet continuously when the engine is running when an air vent without valve is used."

Since I really don't understand a lot of this stuff, I emailed Vetus to ask if continuous spitting was normal, and will post here if I get an answer.

FredV · Dec 22, 2014

Vetus Answer

According to the Vetus support dept.:

"It is normal for the hose/non-valved version on the antisiphon to spit water - accordingly it is wise to plumb the hose overboard/to a location outside the boat. If you do not want the antisiphon to function like this, you can replace the hose/non-valved version with the valved version - either AIRVENTV or ASDV. This will allow ingress of air, but will not permit spitting of water."

Hope this helps!

Blitz · Dec 22, 2014

My boat which is a yanmar 3GM raw water cooled uses a marelon vented loop which is vented directly outside. It almost always has water streaming out of it except at a very low idle.

seadaddler · Dec 22, 2014

Vetus

My vented loop on my Yanmar is made by Vetus and own my boat since
new 2007 and have never seen water under my sealed engine ever before
but I have noticed maybe about 6 months now have noticed water under
the engine but never new where it was coming from and now have checked
the vented loop and watched water spiting out a lot.
I will put a water bottle for the hose to go into for now on and keep a eye
on it and I already did take apart and it was perfectly clean.
Nick

Claude L.-Auger · Dec 22, 2014

Re: Vetus

Nick, if it has a spring that may be weak it will spit water. Good luck

scherzoja · May 24, 2015

Is there any functional difference between these two siphon breaks?

The T is identical in both cases. the only difference is the length of the hose running from HX port to water inject port.

Red one is a T in the 5/8" raw water line (wet exhaust hose) with at 3/8" or 1/4" line going up to cockpit scupper (or transom near centerline).

Green one is a long 5/8" raw water line going up to near the cockpit scupper, where there is a T installed and a 3/8" or 1/4" hose connected to the cockpit scupper (or transom near centerline).

http://s1278.photobucket.com/user/scherzoja/media/siphon break/siphonbreak_zpsn6f1ksk4.jpg.html

Thanks

Diablito · Dec 6, 2015

Kind of the same subject. 1997 Hunter 376 with a Yanmar 3JH2E. I've been trying to find the molded hose that connects to the port side of the stainless tube, on top of which the anti-syphon valve connects. I've checked Yanmar Marine, Hunter Owners, Sailboat Owners, Defender, West Marine, etc., etc., etc.
The molded hose in my boat is in need of replacement and I can't even find it in my manuals.
Any recommendations?
Thank you.Tim

Anti-Siphon ... Dumb Question!!!

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