What is the proper micron reading for complete evacuation in HVAC?

In the context of HVAC service, achieving the proper micron reading during the evacuation process is crucial for ensuring the system is free of moisture and non-condensables. A micron reading of 500 microns is generally accepted as the standard for complete evacuation.

Reaching this level helps to create a deep vacuum, which is essential for removing moisture from the refrigerant lines and the system. Under 500 microns, the chances of moisture forming ice or causing corrosion within the system during operation are significantly reduced. It is important to ensure that the vacuum pump has been allowed to run long enough to achieve this micron level properly and that all connections are secure to prevent leaks and ensure accurate readings.

While values lower than 500 microns might be ideal in certain applications, 500 microns is widely recognized in the industry as a safe and effective target for complete evacuation in most HVAC systems.