It's getting to be that time of year again.  Pretty well everything is 134A now ( as new equipment has been purchased) and not R12.  With the old R12 systems had to add a can every year or so on farm machinery.  Seems like it is the same with the 134A systems now that they have a few years on them.  In the past when I added refrigerant I just added refrigerant and did not add oil.  Some of the 134A cans come with a sealer and oil.  When you top up your 134A systems do you just add 134A or do you add 134A with some oil or sealer.  It would seem after a while that you must lose some oil or does the oil stay in the system and you just need to "top up" the 134A.  Were not talking big leaks here just a can a year or so.

Comments appreciated - thanks....

Whipper.