It appears that there is a nut on the valve pin which needs to be loosened before air can be added or released. I am wondering if it is necessary to depress the valve pin before air can be added to the tube. With the nut on the valve pin loosened, will the pump push air into the tube with out having to depress the valve pin.
I am trying to come up with a system so that I can be confident that the air pressure in the tube is the pressure that was indicated on the pump after the inflator is disconnected. It seems that some air escapes when the inflator is disconnected.
So if someone can explain exactly how these air valves work, then maybe I can put my mind at ease.