ABYC Air Conditioning & Refrigeration Certification Practice Exam

Plugged air filters restrict airflow into the system, which can lead to an array of performance issues. When the amount of air entering the evaporator coil is reduced due to clogged filters, the cooling capacity of the system diminishes. As a consequence, the pressure in the suction line decreases, resulting in low suction pressure.

This low suction pressure arises because the compressor is not able to draw a sufficient volume of refrigerant vapor from the evaporator coil, which is now receiving inadequate airflow. The added resistance from a blocked filter impedes the system's ability to maintain optimal pressure levels, causing it to operate inefficiently. Maintenance of clean air filters is therefore crucial for achieving proper suction pressure and overall system efficiency.