raw water anti siphon/vented loop?

[deniseO30]

Not even sure what it's called. it hangs under my cockpit and drips water on my new PSS seal! not that that's a bad thing... It's gray and made by Vetus. the raw water lines are 5/8 ID and the top of the thingy has a small tube going off into the high point of the exhaust hose.
Question is.. do i need to replace it with the same one? or use a "marelon" vented loop? thanks !

[deniseO30]

bump it up

[sailingdog]

Can you post a photo of it?

[negrini]

installed behind your engine. Salt deposits overtime, will make it useless, and
drip can turn into a real saltwater fall, and ruin your engine. I remember once I opened my engine after months withou inspection, it looked like snowed over it, as water evaporated and a samll layer of salt covered overall the engine after a long time.
Your model should be inspected (by removing its top) and cleaned periodically, and a hose attached to its top tube, should route drips to the bildge, rather over your engine.
The marelon models (i.e. Jabsco and eve Vetus ones) are mostly intended to toalet siphon breakers. Their rubber blade are not so strong to sustain the positive pressure your exaust pose to the system (or negative, depending where you air-broke).
If replacement is what you want, go for the VOLVO model, made out of bronze and more reliable, but will gonna loose the multiple hose diameters feature.

[JohnRPollard]

Denise,

Based on your limited description, it DOES sound like you're describing the anti-siphon vented loop in the raw water cooling system.

The purpose is to prevent raw water -- after shut down -- from continuing to siphon from your intake seacock, through the engine heat exchanger, and ultimately into the water lift muffler. Normally this raw water would be ejected out the tailpipe by exhaust pressure during operation, but absent the exhaust pressure after shut down,the siphoning could fill the waterlift muffler and backflow through the engine exhaust system and into the engine. Hence the siphon break.

If the siphon break is not working, until you get it repaired, you should quickly close the sea-**** immediately after shutting down the engine. (In reality, the vanes of the raw water impeller will often check the flow of the raw water, but it's conceivable they might not so best to be cautious.) Also, I don't see any reason why you couldn't replace the anti-siphon valve with a similar valve from another vendor -- i.e. it doesn't have to be Vetus.

[deniseO30]

Oh My, thanks Negrini! that's it! Now.how do I find the one Volvo makes (been looking) John Ok 'm looking for them now. marelon is the most common.
ps.. I'm assuming I can take it out for now, splice the hoses and do as John suggests.. close the sea valve when not running?

thanks allot everyone!

[sailingdog]

For what size hose: Look HERE about eight items down for the bronze ones.

[chucklesR]

Most common problem is salted and silted up. Peter Compton's 'Troubleshooting Marine Engines' says to just boil 'em, blow 'em clean and put them back. There are no moving parts.

[sailingdog]

BTW, you could probably buy the Volvo version, but it would probably be three-to-four times the price of the ones I linked to above.

[deniseO30]

gotta love you guys! thanks! I found the original but i'm going for the bronze from defender!
fair winds!
Denise