Arkansas HVACR NewsMagazine May 2025 Issue

HVACR NewsMagazine May 2025

Tech News

Deep Vacuums — With Documentation Evacuation gets all of the air, moisture, and non-condensable gases out of the refrigerant tubing. A deep vacuum ensures that a refrigerant is clean, dry, and tight, which reduces the risk of oil contamination and can also confirm whether a system is leak-free. Our process is to pull a deep vacuum below 300 microns on brand-new systems and at least 500 microns on systems that have been in service. Within 10 minutes, we don't want to see the vacuum decay to above 500 microns or 1000 microns, respectively. Apps like measureQuick, MyNAVAC, and BluVac (pictured) may also monitor your decay tests for easy documentation. The system's behavior under deep vacuum can also tell you if you have a wet or leaky system; a wet system will have a sharp rise and then level off, and a leaky system will have a continuous rise.

Residential systems up to 5 tons can usually do fine with pressure tests lasting 30 – 60 minutes, but we've asked our techs to make them last an hour. When you have larger equipment with more refrigerant, such as in light commercial settings, you may need to perform a longer pressure test. (On top of that, if the manufacturer calls for a specific duration, you'll want to follow their instructions.) In refrigeration, the systems are so large that pressure tests may take 24 hours or more. During the course of a pressure test, there may be significant changes in the ambient temperature, and you don't want to mistake pressure changes due to temperature for leaks. You can use calculators like our Nitrogen Pressure Calculator in these situations.