dwn2erths10
+1y
It would only work if you had something to drive the air back into the tank at a higher pressure than what is in the tank at that moment. ie, a new tank of nitrogen has 2000 to 2700 psi in a 100 size cylinder. if you are at 2000 psi, with the regulator set at 250, you would need over 2000 psi to push the air back into the cylinder