HVAC Evacuation. Leak testing by vacuum..500 microns ≠ No Leak 

The only explanation that I have is that when you pull down to 500 µm the boiling temperature of water drops down to 0°F. so if you are working on a unit and it is 35 or 40° outside by pulling down to 500 µm and it holds, you are sure to remove all of the moisture from the system. the lower you bring the pressure the lower the boiling temperature is. Keep in mind that because the new refrigerants are using POE oil, the oil will not release the moisture. So we need to make sure that we get as much of it out of their as possible. I hope this answers your question. And thank you for watching!

​@@AirConAcademythankyou 🙏 now i understand.

Some of the moisture will be removed. But you really need a micron gauge to make sure that you have removed all of the moisture. It is recommended that you pull a vacuum down to 500 µm. it is difficult to say yes that will be long enough because no one really knows how much moisture has gone into the compressor. long before micron gages were invented we would always pull a vacuum for a minimum of 45 minutes. But like I said, it is best to use a micron gauge. Thank you for watching! And I hope this helps!

Thank you for your suggestion. I am trying to make time to make more videos. I will see what I can do. And thank you for watching!

Thank you! I hope I could help. Thank you for watching!