Airtrol question

Timco

I am re-using an expansion tank on my current job that has an odd Crane fitting where I usually like to have an Airtrol, as described in Pumping Away. I have two, and do not know which is better. One has a 10" long tube that extends into the tank, and a manual drain cock, and the other has a 12" tube, but has 2 tubes that extend into the tank (inner & outer), with a plug that goes where the drain cock usually goes that connects with the smaller, inner tube. This plug has a tiny hole in it and if you back it off, opens the small inner tube. Which would you use & why, and does the nipple that connects the Airtrol to the tank set the tube depth inside the tank? Does this fitting automatically set the water depth within the tank?

Thanks,

Tim

Unknown

if ya look in the book....

If ya look in the book, " Pumping Away, It ain't the same, or How Come?" can't remember which but I know its all written by St. Holohan... The single tube is just for letting in air while draining the steel tank. While the double tubings do two things. One is to drain the tank. The second and larger tubing in to prevent temp strafned(sp) and asborbs 02 into water...( or turnover in fisherman's term). Others will explain it better than me but its all in those bibical heating books...