SailNet Community banner
  • SailNet is a forum community dedicated to Sailing enthusiasts. Come join the discussion about sailing, modifications, classifieds, troubleshooting, repairs, reviews, maintenance, and more!

"Thingamajig" what the heck

2K views 16 replies 7 participants last post by  rugosa 
#1 ·
This weekend I was tracing the hose for my seawater cooling system on my new boat (Yanmar 4JH5E). I was fully expecting to see the hose that leads from the heat exchanger to go directly to the mixing elbow. But no, it heads up engine room bulkhead (above waterline) to a "thingamajig" that looks like a sensor or solenoid then another line going back down to the mixing elbow. This seems strange to me and I am half tempted to put in a new short hose that goes directly from the heat exchanger to the mixing elbow. Looks to me as another single point of failure. Thoughts? What is this "thingamajig"?

The line on the right comes from the heat exchanger, the left line goes back down to the mixing elbow.
 

Attachments

See less See more
1
#2 ·
That's looks like an anti siphon device that prevents a vacuum from existing in the system.. AKA a "vented loop". Are there actually wires going to it, or do they just go by?

btw.. don't short circuit it!!
 
#5 ·
Thanks! I bet it is. There is a grey small hose in the pic that leads off from the top to the left of the junction. I was thinking there were wires in it but I bet it leads off to a higher point in the boat. Interesting, I need to track that hose down to see where it goes. More bruised knuckles coming my way.
 
#8 ·
Anti-siphon valve with plastic cover tabs covering the ends of the hose clamps that hold the hoses in place.
 
#9 ·
That valuable information might be in your owner's manual/dvd/webpage or might not. There was likely some installation & maintenance instructions in the box/bag when installed, but way too often that stuff ends up in the assembly shop trash. Better to know and plan for preventative maintenance than be caught in a gale with your pants down:D
 
#10 ·
Boy, am I sooo glad I asked the question and now know that I need to also give it a periodic vinegar bath. I did look in my Beneteau manual and 4JH5E operation and parts manual, nada. I do try to research (RTFM) prior to posting questions:)

We did sort through all the random manuals that came with the boat, a stack 4 feet high. First removed all the versions that are not in english, 70% reduction right there.
 
#11 · (Edited)
Anti siphon. I had one on my boat and replaced it with a bronze type. The vent tube connected to it went into the exhaust hose about 4ft from the transom. Because it had a bad check valve (it's like disc) water was running out of mine when the engine was pumping water. It may be a different set up on yours.

click here for Vetus USA catalog. you will see a whole bunch of them! --> USA They do go bad.


http://www.jamestowndistributors.com/userportal/show_product.do?pid=63153&familyName=Vetus+Anti+Syphon+Device+with+Valve
 
#12 ·
Anti siphon, I call it vacuum break, I had on on my boat and replaced it with a bronze type. For the engine raw water to vacuum break USA They do go bad. it's like a wafer or disk that keeps the water from going out the vent.. but lets air in when the water is not under pressure.

You have the one I had.
So do you have a link to the bronze one that you now have? Great info thanks!
 
#13 ·
I am half tempted to put in a new short hose that goes directly from the heat exchanger to the mixing elbow. Looks to me as another single point of failure. Thoughts?
You have already been enlightened by other posts on the function of that little thingamajig but I just want to add a little about the Extreme Importance of it. On my Yanmar that loop is vented to the outside and 'mud dauber' wasps built a nest in it - stopping it's function. The next time I used the boat it ran fine and I shut down as normal. What I didn't know was that as the engine cooled down sea water was sucked/siphoned into the engine totally 'hydro-locking' it. I was lucky and no water go into my oil and it was a simple pull the injectors and spray in all over my interior while turning it over. That was 3 years ago - no problem. That would probably happen every time if you did as you were tempted to do above ;)
 
#14 ·


I researched it and it's been working fine for about 4 yrs now. they are also used on head lines Vetus didn't seem to any more durable for what it does. But even the bronze ones only have a little wafer for the check valve.
 
#15 ·
I researched it and it's been working fine for about 4 yrs now. they are also used on head lines Vetus didn't seem to any more durable for what it does. But even the bronze ones only have a little wafer for the check valve.
Nice, adding to my future upgrade list. Can you hook in a small vent hose like the Vetus at the top of the cap? Or does it just vent right off the hole in the cap?

It looks like it is very easy to clean the wafer, nice setup.
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top