A ball valve has another very important use in my area. Occasionally I will do a one-man kitchen exhaust system. Often it is very cold - single digit temps are not uncommon. If water is not coursing through the hoses they will freeze in 1 or 2 minutes. Whatta mess. One must get on the roof and activate the trigger immediately. My machine has pressure-activated burner. With a ball valve I can allow water to run slowly without activating the burner, thus preventing freezup and allowing me control not possible with a trigger gun. Wish I had learned about this sooner.
Richard
Richard