[Nordic]

If you're using a bleed/fill tube you should really consider finding a Y-fitting or getting a small res for the purpose of getting rid of the air a little quicker. In my system the water speed forced the bubbles past my bleed/fill tube when I used a 3/8" T-fitting.

FRAGN'STIEN: What do you mean with this statement about the placement of the fill tube?
"make sure it's at the highest point in the system"

That doesn't really make any sense in closed system. Water won't come spurting out unless you've got a serious air-leak, but that is easily solved by plugging the end of the bleed/fill tube or keeping the opening above every other component (where air can enter).