Question about W300 water cooler???

[DisWeld]

I am replacing the torch connection fittings on my water cooler with 5/8"-18 LH threaded fittings so it will work with my other torches. when I took the cover off the water cooler I noticed that on the water supply line to the torch there is a small 1/8" water line that goes from the original fitting back into the water tank. What is that line used for? and will it hurt anything if I dont use that line on the new setup? I will post some pics when I get a chance. Thanks

[performance]

Please post the pics so we can see which line you are talking about.

[Ray]

I beleve that is an air bleed / return to the tank. Keeps air bubbles to MIN.

Probably don’t need it, but it might insure that pressure does not build up if the line is restricted. I noticed if it’s not pointed down and you take of the cap,, well you get it. The Italian pump flat moves some coolant.

[DisWeld]

Sorry the image is so big I dont know how to scale it down. The orange tube is what I was referring to. There is a threaded outlet (I think its a #6-32)on the torch connection fitting that has a hose barb threaded into it and then the hose goes back into the top of the tank. This is on the water out (Cool water supply to torch) fitting. I can make one for my new connections I just wanted to know if it was an absolutely necessary piece and what it was used for.