NATE Air Conditioning and Heat Pumps Practice Exam 2025 – All-in-One Guide to Master Your Certification!

When the heat load on an evaporator increases, the system must compensate for the additional heat being absorbed. This leads to an increase in the amount of refrigerant evaporating within the evaporator. As the evaporator works harder to absorb the increased heat load, the suction pressure—the pressure of the refrigerant vapor returning to the compressor—also increases.

The discharge pressure, which is the pressure of the refrigerant as it exits the compressor after being compressed, can also rise due to the increased amount of refrigerant vapor being processed by the system. This increase in pressure is a direct result of the compressor working harder to manage the higher flow of refrigerant caused by the increased load.

In summary, both the suction and discharge pressures increase as the system adjusts to handle the larger heat load effectively. This demonstrates how the refrigeration cycle responds dynamically to changes in heat load, ensuring efficient operation.