Which of the following can cause an evaporator to freeze up?

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Multiple Choice

Which of the following can cause an evaporator to freeze up?

When the evaporator coil freezes, it’s because the coil becomes colder than the moisture in the indoor air can handle, so water condenses on the coil and freezes. The most direct way this happens is if there isn’t enough refrigerant circulating in the system. A low refrigerant charge lowers the evaporator’s pressure and temperature, so the coil can drop below freezing and moisture freezes right on contact, building ice that blocks airflow and further reduces cooling. Among the options, the direct cause is low refrigerant levels because it directly reduces heat absorption in the evaporator, driving the coil temperature down to freezing. A dirty air filter can contribute by restricting airflow and reducing heat transfer, which can promote frosting in some situations, but the primary and most straightforward cause in this scenario is a low refrigerant charge. The other options do not typically cause the evaporator to freeze.

When the evaporator coil freezes, it’s because the coil becomes colder than the moisture in the indoor air can handle, so water condenses on the coil and freezes. The most direct way this happens is if there isn’t enough refrigerant circulating in the system. A low refrigerant charge lowers the evaporator’s pressure and temperature, so the coil can drop below freezing and moisture freezes right on contact, building ice that blocks airflow and further reduces cooling.

Among the options, the direct cause is low refrigerant levels because it directly reduces heat absorption in the evaporator, driving the coil temperature down to freezing. A dirty air filter can contribute by restricting airflow and reducing heat transfer, which can promote frosting in some situations, but the primary and most straightforward cause in this scenario is a low refrigerant charge. The other options do not typically cause the evaporator to freeze.

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