Which of the following factors can lead to increased suction pressure in a refrigeration system?

In a refrigeration system, suction pressure is critical for maintaining proper operation and efficiency. The factor that leads to increased suction pressure is the presence of oversized metering devices. Large metering devices can allow more refrigerant to flow into the evaporator than what is being absorbed, resulting in an elevated suction pressure. This can occur because the increased flow may fail to be adequately vaporized by the evaporator coil, allowing excessive refrigerant vapor to build up in the low-pressure side of the system, thus raising the suction pressure.

Understanding the impact of metering devices is essential for technicians, as oversized devices can disrupt the balance between the refrigeration cycle's components. Proper sizing is necessary to ensure that the system operates within its design parameters, maintaining efficiency and preventing undue stress on components that could lead to failures or inefficient cooling.

The other options, such as undersized ductwork, excessive superheat, and low refrigerant charge, have different effects on the system. For instance, undersized ductwork can create airflow restrictions, while excessive superheat and low refrigerant charge typically lead to lower suction pressures rather than increased ones.