Which practice helps avoid water and moisture problems in a refrigerant system?

• A. Proper evacuation during charging
• B. Using only dry refrigerants
• C. Running the system continuously
• D. Avoiding any evacuation

Answer: (A)

Moisture in a refrigerant system causes acids, corrosion, and ice that can clog metering devices and degrade lubrication. The most reliable way to prevent these water-related problems is to evacuate the system during charging. Pulling a deep vacuum removes air and moisture from the entire system before the refrigerant is introduced, often achieving a vacuum around 500 microns or lower. This “dry start” stops moisture from reacting with oil and refrigerant and reduces the risk of acid formation and internal damage. Simply relying on a dry refrigerant won’t remove moisture that’s already in the lines or trapped in oil, and running the system or avoiding evacuation doesn’t remove water — it may circulate or leave moisture behind.