Why doesn't my dehumidifier remove moisture?

Replace the dehumidifier evaporator thermistor

The evaporator thermistor is a temperature sensor on the evaporator coils. It communicates the temperature of the evaporator coil to the electronic control board; if the temperature is too low, the electronic control board detects excessive frost and begins the defrost cycle. If the thermistor isn't working properly, the electronic control won't defrost the coils. Replace the evaporator thermistor if it doesn't detect the evaporator temperature.

Replace the dehumidifier compressor

The compressor is a pump that compresses the refrigerant that runs through the sealed system in the dehumidifier. If the compressor doesn't run when activated, have a refrigerator service technician replace it; by law, an EPA-licensed technician must complete this repair because it involves refrigerant.

Replace the dehumidifier fan motor

The fan motor rotates the fan blade that pulls air in through the front of the evaporator and pushes air out through the back of the condenser coil. The moisture in the air pulled in through the evaporator condenses on the evaporator coil. The air pushed out through the condenser causes the refrigerant to condense to a liquid. Replace the fan motor if it doesn't run when activated.

Replace the dehumidifier condenser coil

The condenser is a heat exchanger that cools and condenses the hot, high-pressure refrigerant gas to a liquid state. The refrigerant then flows through the evaporator coil. If the compressor is running but the condenser cool and the evaporator is warm, the condenser or evaporator may have developed a refrigerant leak; by law, an EPA-licensed technician must to this repair because it involves refrigerant.