Are you keeping the Gas Ballast open when starting?
Originally posted by huskerdu
I have been using the same jb 3cfm pump for 20 years been a good unit on new installs and light pumpdowns after fixing leaks in linesets, but when I have had burnouts or trying to vacuum condensers that have had freon and oil in them I have bad luck!! It seems that it takes forever to get the 500 micron on the gauge that I want , even had to settle for a little higher # a couple times. Been talking to the boss hard about a 6cfm but not getting anywhere. Maybe after the next 4 hour pumpdown time he will think again.
I change the oil religeously after each use!!!