Which component’s failure is listed as a possible cause of an iced-up evaporator in the given material?

Which component’s failure is listed as a possible cause of an iced-up evaporator in the given material?

• A. Bad defrost timer motor
• B. Failed compressor oil pump
• C. Faulty condenser fan blade
• D. Restricted liquid line filter

Answer: (A)

Iced-up evaporator happens when the defrost cycle isn’t working. The defrost timer motor controls when the evaporator coil goes into defrost so that any frost that forms can melt away. If that timer motor fails, the system may stay in cooling mode or fail to enter defrost at the right times, allowing frost to accumulate on the coil. This frost buildup blocks air flow and reduces cooling efficiency, leading to an iced evaporator. The other components don’t directly cause this specific issue. A failed compressor oil pump affects lubrication and can damage the compressor, but it doesn’t by itself create ice on the evaporator. A faulty condenser fan blade impairs heat rejection at the condenser, which can raise pressures and reduce efficiency, but it doesn’t trigger frost on the evaporator. A restricted liquid line filter limits refrigerant flow to the evaporator, affecting cooling performance, but it’s not the typical cause of ice buildup from a defrost failure.

Iced-up evaporator happens when the defrost cycle isn’t working. The defrost timer motor controls when the evaporator coil goes into defrost so that any frost that forms can melt away. If that timer motor fails, the system may stay in cooling mode or fail to enter defrost at the right times, allowing frost to accumulate on the coil. This frost buildup blocks air flow and reduces cooling efficiency, leading to an iced evaporator.

The other components don’t directly cause this specific issue. A failed compressor oil pump affects lubrication and can damage the compressor, but it doesn’t by itself create ice on the evaporator. A faulty condenser fan blade impairs heat rejection at the condenser, which can raise pressures and reduce efficiency, but it doesn’t trigger frost on the evaporator. A restricted liquid line filter limits refrigerant flow to the evaporator, affecting cooling performance, but it’s not the typical cause of ice buildup from a defrost failure.