A possible cause of a compressor running continuously is

• A. Low refrigerant
• B. High refrigerant
• C. Clogged air filter
• D. Overload protector tripping

Answer: (A)

When the refrigerant charge is too low, the system can’t absorb heat from the evaporator as needed. The evaporator pressure stays low and there isn’t enough refrigerant to carry heat away efficiently, so the space doesn’t reach the thermostat’s cooling setpoint. Because cooling isn’t achieved, the thermostat keeps calling for cooling, and the compressor runs continuously in an attempt to meet the demand.

High refrigerant would raise pressures and can trigger protections rather than keep the compressor running nonstop. A clogged air filter reduces airflow and can cause other issues (like frost or short cycling) but isn’t the typical cause of a compressor staying on all the time. The overload protector tripping would stop the compressor instead of letting it run continuously.