Suction-line filter-driers are fitted with gauge connections to determine what maintenance action?

• A. Perform Accurate Superheat Calculations
• B. Change the Filter-Drier
• C. Prevent Flash Gas in the Drier
• D. Avoid Excessive Compressor Load

Answer: (B)

Suction-line gauge connections are there to tell you when the filter-drier needs replacement. The filter-drier removes moisture and particulates from refrigerant, and over time the desiccant can become saturated or the element can clog, causing a change in suction pressure or an abnormal pressure differential across the drier. When the readings indicate degraded performance or the moisture indicator shows saturation, it signals that the drier should be changed to maintain proper flow and protect the system. Other readings like superheat calculations, flash-gas prevention, or compressor load aren’t directly determined by these suction-line gauges in this maintenance context.