How Do Dehumidifiers Work?

WARNING!

To avoid personal injury or death, disconnect your appliance from its power source before you start any troubleshooting or repair work. Use caution when working inside any appliance.

Dehumidifiers are very similar to air conditioners in that they both have hot and cold coils. Dehumidifiers use refrigeration and condensation principles to remove water from the air, and thereby reduces the relative humidity of the room.

The basic components of a dehumidifier include a circulating fan, a compressor, a condenser coil (hot coil), and an evaporator coil (cold coil).

A compressor compresses the refrigerant gas, which causes it to become a hot, high-pressure gas. Next, this hot gas flows through a set of condenser coils where it dissipates its heat, and condenses into a liquid. Following that, the liquid flows through what's known as an expansion valve or capillary tube. During this process, the liquid expands and evaporates to become a cold, low-pressure gas. This cold gas flows through another set of coils called evaporator coils, which allows the gas to absorb heat. By absorbing that heat, it also collects moisture by condensing it from the air. A fan blows over the hot and cold coils to help in the process of heat transfer.

The cold coils act just like a cold glass of lemonade on a hot summer day. The moisture in the air that goes past it condenses on the sides of it, and then drips down the sides of it forming a little puddle.

In a dehumidifier, the fan pulls room air over the cold evaporator coils, which allows the water in the air to condense on the coils. This water drips into a collection bucket which you empty periodically. The air is then pulled over the warmer condenser coils which warms the exiting air. Because the air is heated as it exits, it further lowers the relative humidity of the air.

Most dehumidifiers have sensors to detect when the bucket is full. When the sensor detects that the bucket is full, it will send a signal to turn off the dehumidifier until the bucket is emptied. This will help prevent overflow and spillage of the condensed water.

Because dehumidifiers constantly have moisture sitting in the holding tanks and on the evaporator coils, you must clean them often to prevent mold spores and bacteria from growing.

Normal operating sounds can be caused by the compressor, fan, or coil tubes vibrating.

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Dehumidifier Repair Questions and Solutions
1. Why won't the dehumidifier turn on? 2. Why don't I feel any air flow from the dehumidifier? 3. Why doesn't the reservoir fill? 4. Why is the reservoir filling so fast?		5. Is it expensive to run a dehumidifier? 6. How often do I need to empty the dehumidifier? 7. What if I don't want to constantly empty my dehumidifier bucket? 8. Why are the evaporator coils freezing up?		9. Can I run it year round? 10. What is relative humidity? 11. Why does the dehumidifier run so much?

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