What is the purpose of the access ports on a filter drier in a refrigerant system?

• A. To Measure Temperature Change
• B. To Measure Pressure Drop Across The Filter Drier
• C. To Inject Refrigerant
• D. To Relieve Pressure

Answer: (B)

Access ports on a filter drier are there to measure the pressure on each side of the drier, so you can determine the pressure drop across it. This pressure differential is the key clue to whether the drier is flowing freely or becoming restricted or clogged. If the drop increases beyond the system’s normal range, it indicates the drier may be restricting refrigerant flow and may need attention or replacement. These ports aren’t meant for injecting refrigerant or releasing pressure—their primary purpose is to provide a window into how well the drier is performing, by allowing accurate pressure measurements across it.