Why are suction line filter dryers equipped with two service ports?

Suction line filter dryers are equipped with two service ports primarily to enable checking the pressure drop across the dryer. This is essential for monitoring the operational condition of the refrigerant system. By assessing the pressure drop, a technician can determine whether the filter dryer is obstructed or if it is functioning properly. An excessive pressure drop could indicate that the filter dryer is clogged or that there may be other issues within the refrigeration system that need addressing.

Having two service ports allows for accurate measurements; one port can be used to measure the pressure before the dryer, while the other measures the pressure after the dryer. This information is vital for maintaining an efficient refrigeration cycle and ensuring that the system operates within manufacturer specifications.

The other choices present alternatives that may seem plausible but do not accurately reflect the primary design purpose of the dual ports in suction line filter dryers.