[C320-list] antisiphon valves

[harold brown]

Thanks for all the information on the valves. This
list is invaluable to someone just beginning. Now
another question.  My genoa winches are thru bolted
but only have a small washer on the bolt. Is there a
reinforcement plate in the glass and if not should one
fit one over the bolts?  It seems like a lot of force
on just 4 small washers. I understand the deck mounted
winches are bolted into a threaded plate imbedded in
the deck. Thanks. Jim Brown
--- Scott Thompson <sthompson at toad.net> wrote:

> The purpose is to to create a "vented loop" above
> the water line in 
> order to prevent a siphon forming when the
> associated system isn't in use.
> 
> The vented loop in the cockpit locker is for the
> engine cooling system 
> and is in a loop between the engine heat exchange
> and the exhaust elbow. 
>   Without this vent it's possible that when you shut
> down the engine, 
> cooling water could continue to flow due to siphon
> action from the 
> exterior of the boat through the raw water pump and
> heat exchanger into 
> the exhaust elbow and muffler.  Without pressure
> from the engine exhaust 
> to clear the muffler, this could eventually cause
> the muffler to fill 
> with water, possibly allowing water to back up
> through the exhaust elbow 
> into the engine itself, which obviously is not a
> good thing.
> 
> The one for the head is intended to prevent flooding
> the boat from water 
> siphoning through the head pump into the bowl and
> overflowing.  The 
> other one in the head cabinet is for the shower sump
> pump, where water 
> normally flows out of the boat, but could reverse
> due to siphon action.
> 
> Scott Thompson
> Surprise, 653
> 
> harold brown wrote:
> > Thank for the information. Mine are now screwed
> down
> > tight they were all open (including the one for
> the
> > engine). Funny the owner's manual maken no mention
> of
> > it. What is the purpose of having the vented valve
> in
> > the first place? Jim Brown
> > --- Quentin Murphy <qmurphy at sympatico.ca> wrote:
> > 
> >> These should be screwed tight.  Some 320s also
> have
> >> another anti-siphon
> >> valve (engine) in the main cockpit locker.  Mine
> >> loosened last year and
> >> caused the aft cabin berth (including the
> bedding)
> >> to get a good soaking.
> >> It took months to get the space under the locker
> dry
> >> and every time the boat
> >> heeled, it re-wetted the berth.  Not too
> pleasant!
> >>
> >> Quentin Murphy
> >> Celtic Knot #667
> >>
> >> -----Original Message-----
> >> From: c320-list-bounces at catalina320.com
> >> [mailto:c320-list-bounces at catalina320.com]On
> Behalf
> >> Of harold brown
> >> Sent: July 4, 2007 3:45 PM
> >> To: c320-list at catalina320.com
> >> Subject: [C320-list] antisiphon valves
> >>
> >>
> >> Probably a dumb question but are the screw down
> caps
> >> on the 2 antisiphon valves in the head cabinet
> >> supposed to be screwed down or left partially
> open?
> >> Jim Brown     Desafinado
> >>
> >>
> >>
> >>
> >
>
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> >>
> > 
> > 
> > 
> > 
> >  
> >
>
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> > 
> 
> 



       
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