December 22, 2014

How does a dehumidifier work?

By Sears PartsDirect staff
How a dehumidifier works.

A dehumidifier is an appliance that removes moisture from the air inside a room or basement, making it more comfortable.

Moist air enters the dehumidifier and crosses refrigerant-cooled coils, causing the moisture in the air to condense on coils within the machine. The moisture then collects in a drip pan or bucket for disposal, while the air passes through a warm condenser or heat recovery coil. The slightly warmed air exiting the dehumidifier is dry and warm.

Three things cause the dehumidifier to turn off:

  • The dehumidifier has a humidity control that you can set to regulate the amount of humidity removed from the air. When the dryness level is achieved, the dehumidifier turns off.

  • The dehumidifier turns off when the moisture collection bucket is full. The bucket must be removed and emptied before the unit will operate again.

  • The dehumidifier uses a de-ice control to turn off the cooling unit if the electronic control detects ice on the coils. After the ice melts, the dehumidifier turns back on.

Symptoms common to all dehumidifiers

Choose a symptom to see related dehumidifier repairs.

Main causes: weak or dead batteries, out of range, radio frequency interference
Main causes: lack of electrical power, wiring failure, electronic control board failure, user interface control failure
Main causes: collection bucket not installed, collection bucket full of water
Main causes: loose fan motor mounting screws, loose compressor mounting bracket screws, bad fan, faulty compressor
Main causes: dirty air filter, clogged grill, dehumidifier placed too close to the wall, dehumidifier too small for the space
Main causes: clogged drain hose, drain hose not properly connected
Main causes: dehumidifier too small for the space, bad humidity sensor, faulty evaporator thermistor, low refrigerant, bad compressor
Main causes: collection bucket not installed correctly, cracked collection bucket, loose drain hose connection
Main causes: room temperature below 65 degrees Fahrenheit, control system failure
Repair guides common to all dehumidifiers

These step-by-step repair guides will help you safely fix what’s broken on your dehumidifier.

How to replace a dehumidifier electronic control board

If the dehumidifier won’t power up because the control board has failed, use the steps in this repair guide to replace the electronic control board and fix your dehumidifier.

Repair difficulty
Time required
 45 minutes or less
January 1, 2014
By Lyle Weischwill
How to replace a dehumidifier sensor assembly

If the humidifier sensor doesn’t properly detect humidity or evaporator temperature, install a new sensor assembly, following these steps.

Repair difficulty
Time required
 45 minutes or less
How to replace a dehumidifier user interface control board

If the dehumidifier doesn’t respond when you try to set it, follow these steps to replace it.

Repair difficulty
Time required
 30 minutes or less
Articles and videos common to all dehumidifiers

Use the advice and tips in these articles to get the most out of your dehumidifier.

January 6, 2015
Dehumidifier doesn't collect water
By Sears PartsDirect staff

Why your dehumidifier doesn't collect water and how to resolve the problem.

December 22, 2014
How does a dehumidifier work?
By Sears PartsDirect staff

Discover how a dehumidifier works.

December 16, 2014
How to clean a dehumidifier
By Sears PartsDirect staff

How to clean a dehumidifier for more efficient operation.