Hi Elmer, While i appreciate your input...You may notice that I am an instructor and I own a dive shop...and average about 700 dives a year. I own eight DIN regs, and not counting my shop stuff 6 yoke regs. I deal with the set up and take apart of about 12 sets of gear a day, ( Very conservative) that`s about 7,000 times a year. So in my experience of roughly 35-40,000 set ups in my diving career. I believe I am aware of any remaining gas in the systems....and usually I do not dive an spg but AI....not a lot of residual gas in that sending unit...Is this a daily problem....no, it has happened four or five times. Have I ever found the cause ? No, have I bled the tanks empty to remove all possible pressure from the system...yes..with that additional information, if any body has a suggestion as to why I would experience this periodic lock up of a din system, it would be useful..
Thanks.