Which statement about flooded evaporators is incorrect?

• A. The evaporator is flooded with liquid refrigerant.
• B. Heat is absorbed as the refrigerant boils.
• C. Vapor rises from the liquid.
• D. Refrigerant boils directly inside the evaporator coils.

Answer: (D)

Flooded evaporators keep the entire evaporator filled with liquid refrigerant. As heat is added, this liquid boils, absorbing latent heat and turning into vapor that then rises and exits with the suction stream. The boiling occurs in the flooded liquid throughout the evaporator, not only inside the metal tubes themselves. The coils merely provide the heat transfer surface; the vapor is generated in the liquid mass surrounding and within the flooded space. So saying that refrigerant boils directly inside the evaporator coils suggests boiling only inside the tube walls, which isn’t how a flooded evaporator operates.