1. So when you press the purge button (which is pressing on the diaphragm) the air RUSHING/GUSHING OUT of the second stage mouthpiece is at ambient pressure? Is that why it is rushing out so quickly bubbling all the way out like a fountain and isn't coming out at intermediate pressure and is subsiding as it moves away from the valve opening? The intermediate pressure just COMPLETELY and utterly goes down from 140 psig down to 0 psig ambient instantaneously? Is this what you are saying?
2. First stage intermediate pressure is present in the hose and the part of the SS before the SS stage valve opens. It is intermediate pressure in all parts upstream of the valve when it is closed to the first stage including any parts of the SS stage housing that is upstream of the valve.
2. First stage intermediate pressure is present in the hose and the part of the SS before the SS stage valve opens. It is intermediate pressure in all parts upstream of the valve when it is closed to the first stage including any parts of the SS stage housing that is upstream of the valve.