Best vented loop? Maintenance-free?

[svJasmine]

In my "not so humble" opinion, the best way to do this is to make a loop out of something, or use your current loop and take that valve off.

Run a hose to the cockpit and make a little 1/8 inch outlet that will spray right down in to the cockpit drain. I used a vent fitting for a fuel tank. Make sure there is enough restriction that you don't dump much water there so you don't starve the exhaust. Mine gets restricted down to 1/8 inch.


This will keep the loop open at all times when there is siphon, and tell you if there is water coming out the exhaust all the time. If you see steam there, you have a problem.


never needs maintenance.


Rich

[svJasmine]

I see my response is much like John's above.

[Uncle Bob]

Originally Posted by roverhi

Replace the valve with a small diameter hose barb, attach a hose and run the hose up as high in the hull as you can and then run overboard to thruhull in some inconspicuous place. Did that with the vented loop on my Volvo which kept sticking shut and filling the engine with sea water. One time fix and never a problem there after.

+1 Mine runs into the cockpit drain, easy to see if it is running, bleeds off very little water and never clogs up, whats not to like?

[Clivevon]

Quote:
Originally Posted by roverhi View Post
Replace the valve with a small diameter hose barb, attach a hose and run the hose up as high in the hull as you can and then run overboard to thruhull in some inconspicuous place. Did that with the vented loop on my Volvo which kept sticking shut and filling the engine with sea water. One time fix and never a problem there after.

+1 more.

[Suliwar]

[kenbo]

Originally Posted by Copacabana

Good advice GoAway. I just installed my (last!) spare Groco rubber valve. It would be easy to remove it every 6 months for a good cleaning. I might stick with the Groco if this works. I did save the old one and I am soaking it now in dish soap and vinegar. Perhaps it will come back to life... (I'll keep it as a spare). I just don't know why a little bit of rubber and stainless steel costs US$45. It seems Groco could price this lower to keep customers happy and loyal to the brand.

Also, thanks for the Scot suggestion above. I checked their site and it looks like a good product. It does state, however, that the valve won't open unless the vented loop is installed at least 2 feet above the waterline. I'm not sure mine is, but I'll check.

The Forespar also looks good and the replacement parts are much cheaper.

My vented loop was at 15" above the water line and worked a treat.

[CarinaPDX]

I used a small (1/4") hose to the cockpit footwell instead of the valve. It worked a treat. Unfortunately it was at the front of the cockpit and the drains are at the rear so the walking surface would become wet and slippery. Even if I could have run the hose down into the drain that wouldn't have worked reliably as a siphon-break as the top of the drains is only a few inches above the waterline when not moving, and water can actually come back into the footwell in heavy conditions if the ball check valve doesn't fully seal. So keep in mind that if you go with a small hose it needs to stay well above the waterline in all conditions or you will no longer have a siphon-break.


Greg

[HopCar]

The valve in the Groco vent looks very similar to the valves used in old style Jabsco diaphragm pumps. They are less than half the price of the Groco valve.
What is the outside diameter of the Groco valve?
https://www.go2marine.com/product/19...SABEgLO3_D_BwE

The caps on Groco vented loops have 1/2” NPT threaded holes. You could remove the Groco valve, replace the cap, put a 1/2” X 1/8” pipe bushing in the hole and screw in a Scot Ardox valve.
Boatswain's Locker - VB18

[JOHNMARDALL]

The link below will take you to a web page showing all of our air vents. The one you want is the ASDV. Please feel free to contact me at jmardall@comcast.net if you need more information.


https://www.vetus.com/en/exhaust-systems/air-vents.html


All the best
John M

[hellosailor]

copa-
FWIW soaps break down rubber parts. That's why drag racers literally put soapy water on their tires, to get better traction before they peel out.
You might be better off soaking the part in a rubber cleaner/protectant, or if you can access an ultrasonic cleaner (most jewelers have them for routine cleaning) use that instead.

[agb512]

Did the same except ran the tube to the cockpit so I could always see water coming out: no need to guess if the water is flowing.

[Chris777]

My head raw water inlet has a antisiphon valve that constantly causes the head to loose its prime. If I put it high so seawater dont flood the head it will not prime. And if I lower it head fills up with water. Any ideas folks?

[Uncle Bob]

Originally Posted by Chris777

My head raw water inlet has a antisiphon valve that constantly causes the head to loose its prime. If I put it high so seawater dont flood the head it will not prime. And if I lower it head fills up with water. Any ideas folks?

Where is the anti siphon valve located, in the suction hose or between the pump and bowl?
I believe that it should run from the through hull to the pump thence through a vented loop above the heeled waterline and back to the bowl. This arrangement will not cause the pump to lose prime and will not allow water to flow in when not intended.

[Chris777]

Uncle Bob, that makes perfect sense...Yes it is between the thru hull and the pump. Should be an easy fix. Thank you

[sv.antea]

S.V. Jasmin. Have been installing the system you suggest on boats for long time. On my boat, the engine is right behind the mast, so I just run some tubing up the mast ~10 ft from the top of the loop. there is never enough pressure to push water out of there. One of my customers, when I suggested the cockpit drain route, said, "hell, just make it piss on my foot, so I know I have cooling water" lol.
And, I have seen few installations, where there is just a loop of largish dia hose from the heat exchanger to the exhaust mixer clamped to the underside of the cockpit without vent (it must be well above water line) that worked without problem. When the engine is shut off, the water from the hose naturally drains into the mixer and hence into the muffler/aqualift, breaking any siphon. To be sure, the impeller better be in good shape. But why not run a vent into the cockpit drain.