Low suction pressure in an HVAC system can be caused by which of the following?

Low suction pressure in an HVAC system is often associated with airflow issues. When there is inadequate airflow across the evaporator coil, it can lead to a drop in the suction pressure. This lack of airflow prevents the refrigerant from absorbing enough heat, which can cause the pressures to fall below normal operating ranges. Factors like dirty filters, blocked ducts, or problems with the blower fan can all reduce airflow, leading to this condition.

Although other options, such as clogged refrigerant lines, can influence pressures, they typically affect both the suction and discharge sides of the system, while airflow issues more directly impact the suction pressure due to reduced heat exchange efficiency. Understanding the relationship between airflow and pressure in an HVAC system is crucial for effective troubleshooting and maintaining optimal performance.