Let me put it this way. I had all the valves and bungs out of my tank when I painted it. All this purging bull is just that,bull. When I got done painting it I put the bungs back in and the valve back in and took it to the propane guy to have it filled and he filled it just like he always did. Their was no purging. The propane goes in the air comes out the bleeder, that's it. My guess is the valve is bad. Others mileage may vary