A simple perhaps stupid question

[c_witch]

Ok are vented loops bi directional in the flow of liquid thru them? I recently hooked up the loop on the boat and filled the msd holding tank with water and flipped on the macerator to pump it out to check the connections for leakage and proper working. The connection on the right side of the loop to the hose from the macerator was spraying some water. I retightened it and tried again and still the same problem but less spraying this time. The vent is a 1'' Johnson one and yes the seacock was OPEN at the time as the water was being expelled from below the hull via the thru hull.

c_witch

 

[Crazy Dave Condon]

you hit on the nailhead as some vented loops are one direction. Take it off and check it.

crazy dave

 

[Bill Roosa]

A vented loop is bidirectional. The vent works on the principal of pressure closes it and a vacuum opens the vent. So when you run a fluid through it in either direction the valve should close. As the fluid stops and the vent is above the level of the static fluid level the fluid pressure goes below atmospheric and the lower pressure allows the vent valve to open.
The vent is just a one way valve allowing flow into the hose but not out, plain and simple

The location of the leak is not even in the vent so all you have is a loose connection or miss fitting hose/ loop

 

[Joe]

Don't put a vented loop between the holding tank and the through hull. You put the vented loop on the seawater INTAKE line between the head pump and the TOILET.... that's to prevent the seawater from siphoning into the toilet bowl when the msd is below the waterline.

You can also put a vented loop on the MSD pump's discharge line..... on mine it goes to a Y-valve.... when the valve is on direct discharge it prevents siphoning back through the exit through hull to the bowl.... when the valve is switched it prevents the holding tank contents from working it's way back to the bowl.

I'm not sure what benefit there is by putting an anti-siphon device after the holding tank.... the only place water is going to be siphoned into the boat is through the toilet bowl.... So that is why you essentially protect both sides with vented loops.

Read this: http://www.xylemflowcontrol.com/files/itemdoc1391.pdf

 

[c_witch]

A vented loop is bidirectional. The vent works on the principal of pressure closes it and a vacuum opens the vent. So when you run a fluid through it in either direction the valve should close. As the fluid stops and the vent is above the level of the static fluid level the fluid pressure goes below atmospheric and the lower pressure allows the vent valve to open.
The vent is just a one way valve allowing flow into the hose but not out, plain and simple

The location of the leak is not even in the vent so all you have is a loose connection or miss fitting hose/ loop

Thanx Bill, I kinda figured that this thing should be bi-directional as far as the actual flow of liquid goes. Chalk it up to another incompatability with various marine parts. In this case a vented loop claiming to be 1'' but the nipples for the hose attachment being slightly on the small size. The hoses fit both the macerator outlet and the nipple on the ballcock without issue so I'll take the issue to be with the vented loop.

c_witch

I added a bit of silicone to the nipple and let it set slightly and then applied the clamp again. I have not checked for leakage as yet though.