Evaporators should never exceed a pressure drop of:

Evaporators should never exceed a pressure drop of:

• A. 1 psig.
• B. 1.5 psig.
• C. 3 psig.
• D. 2 psig.

Answer: (D)

When refrigerant boils inside the evaporator, the system’s suction pressure is set by the pressure difference across the coil. Keeping that pressure drop small helps maintain a healthy suction pressure entering the compressor, ensures the refrigerant fully evaporates in the coil for effective heat transfer, and reduces the risk of abnormal compressor operation or oil return problems. The commonly accepted maximum for evaporator pressure drop is about 2 psig. Exceeding this limit means the outlet pressure falls too far below the inlet, hurting performance and increasing the chance of issues with suction stability and liquid refrigerant reaching the compressor. Therefore, the best answer is 2 psig.

When refrigerant boils inside the evaporator, the system’s suction pressure is set by the pressure difference across the coil. Keeping that pressure drop small helps maintain a healthy suction pressure entering the compressor, ensures the refrigerant fully evaporates in the coil for effective heat transfer, and reduces the risk of abnormal compressor operation or oil return problems. The commonly accepted maximum for evaporator pressure drop is about 2 psig. Exceeding this limit means the outlet pressure falls too far below the inlet, hurting performance and increasing the chance of issues with suction stability and liquid refrigerant reaching the compressor. Therefore, the best answer is 2 psig.