What procedure should be followed to thoroughly dry a wet system exposed to atmosphere?

To thoroughly dry a wet system that has been exposed to the atmosphere, the preferred method is to perform a multiple evacuation procedure. This approach involves evacuating the system in stages to significantly reduce moisture content.

When a refrigeration system is exposed to atmospheric conditions, moisture can enter the system, creating the potential for freezing and other damage. Simply evacuating the system once might not be sufficient to remove all the moisture. A multiple evacuation procedure allows for effective moisture removal by repeatedly pulling a vacuum on the system, which helps to vaporize any absorbed moisture through the refrigeration oil or within the lines. Each time the vacuum is broken (usually with nitrogen), moisture is removed, and the process can be repeated until the desired moisture level is achieved.

This method is essential for ensuring the longevity and efficiency of the system once it's recharged with refrigerant, as even small amounts of moisture can lead to corrosion, freezing, and system failure.