Don’t Sweat It: Dehumidifier Repair and Troubleshooting

Dehumidifiers are essential for maintaining comfortable and healthy indoor air, especially during the summer or in humid climates. They help to reduce excess moisture, prevent mold growth, and improve air quality. 

But like any household appliance, dehumidifiers can sometimes act up or experience issues that affect their performance and efficiency. 

In this article, we go through the possible causes, and discuss dehumidifier repair and troubleshooting.

8 Common Issues Why the Dehumidifier is Not Working

1. Dehumidifier won’t turn on

Most dehumidifiers have an indicator light to show it is receiving power, as well as its operational state. If your dehumidifier will not power on:

• Check that it is plugged into the wall, and the outlet has power.
• Examine the wiring.
• Check for blown fuses or tripped circuit breakers.

If the indicator light is on but the dehumidifier is not functioning: 

• Check the water reservoir. In some models, the unit shuts off automatically if the water tank is full, to prevent overflow and damage to the unit and surrounding area. 
• Check the tank placement. It may be improperly seated or loose. Some tanks are connected to an activation switch or sensor. Try removing and re-adjusting the tank.

2. There is weak or no air flow

Dehumidifiers use a fan to suck air into the unit so the excess moisture can be removed. A blower then recirculates the air back into the room. If the air flow seems to be weak or non-existent:

• Check the fan. It could be stuck, malfunctioning, or broken. Hold a piece of paper to see if it’s drawn in by the fan.
• If the fan is working, examine the blower. Hold the same piece of paper and check that it flutters away from the dehumidifier vent.
• If both are working, look at the filters for signs of clogging or replacement. A clogged filter hinders air flow and strains the dehumidifier’s motor. It also traps mold and can result in poor air quality. Clean or replace the filter as required.
• Move the position of the dehumidifier. Make sure both inlet and outlet are not obstructed by household items, furniture or the wall. 

3. Tank issues

If the tank seems to require emptying too frequently:

• Increase the humidistat level. A range of 40-50% ensures comfort while reducing the frequency of water changes.
• The unit may be too close to an appliance that generates humidity, such as a stove or cooktop.
• If the dehumidifier uses a drain line, inspect the line for signs of kinking or clogging.

If the tank seems to fill up too slowly:

• Decrease the humidistat to allow the dehumidifier to remove more moisture from the air.
• Make sure the fan is not blocked or obstructed by large furniture.

If the tank doesn’t ever seem to fill up:

• Check the dehumidifier coils. A frozen coil is unable to remove moisture, and the air simply gets recirculated back into the room.
• Defrost the unit and clean up any excess condensation to minimize freezing.

4. Premature shut off

Dehumidifiers are designed to switch off once the room reaches the desired humidity level. If you feel the room still remains humid:

• Lower the humidistat level so it will continue to remove moisture from the space.
• Check if the timer may have been accidentally turned on.
• Check the tank to see if it’s full, or properly seated.

5. Dehumidifier runs continuously

At the opposite end of the spectrum, we have a dehumidifier that won’t stop running. If the unit has been working for longer than normal:

• The humidistat may be set too low for the environment. Adjust the humidistat to a higher, more reasonable level.
• There may be leaks or open windows in the room. This causes humid air from outside to enter, taxing the dehumidifier. Keep windows and doors closed while the unit is running, and check for any air leaks in the room.
• The unit may have a mode where it runs all the time. Look for a button that may control this function.

6. Ice forming on coils

Ice formation is not normal and could damage the dehumidifier. When this happens:

• The air temperature may be too low for the model. Ensure the dehumidifier is suitable for the operating temperature; some models are not meant to work in colder environments.
• The airflow may be restricted. Check whether the air filter is clogged or dirty, and make sure nothing is blocking the air intake or exhaust.

7. Water leaks

Like ice, water can damage the dehumidifier as well the surrounding area. 

If the dehumidifier has a tank:

• Make sure it is properly aligned and seated.
• Regularly empty the tank before it becomes full.

If it uses a drainage system:

• See if the hose is properly connected.
• Check for loose connections or fittings.
• Examine the hose for tears or damage.
• Make sure the hose has no kinks that could cause pooling or backflow.

8. Unusual noises during operation

Apart from the fan and blower, dehumidifiers are meant to be quiet by design. If you hear an unusual noise it didn’t emit before:

• It could indicate a struggling motor caused by poor airflow. Clean the filter and check for blockages.
• Rattles or vibrations could be caused by loose internal components. Check for loose parts and ensure the lid and tank are properly seated.

If the noise persists, unplug the unit and contact a professional. 

Dehumidifier Repair and Common Points of Failure

Like any household appliance, a dehumidifier is made up of a number of components that may need repair or replacement over time.

Keep an eye out for these major parts:

Fan

Can become clogged, suffer broken blades, or simply cease functioning with age.

✔ Check that the fan rotates freely and clean up encrusted dirt and debris

✔ Inspect the fan blades for misalignment, which can impede rotation. Some manufacturers offer replacement blades, which can be easily installed with a screwdriver.

✔ If neither works, the fan motor may be at fault and will need to be replaced.

Humidistat

This automatically switches the dehumidifier on or off when the humidity reaches the preset levels. If the dehumidifier doesn’t switch on or off automatically, then this component may be broken.

✔ Use a multimeter to check for continuity

✔ Make sure the model is properly seated. Most humidistats are located just under the cover panel.

Filters

Like other appliance filters, they need to be cleaned or replaced periodically.

✔ A portable unit typically needs to have the filter cleaned every month, or more during the warmer season.

✔ Replaceable filters should be swapped out every 3 months

✔ For whole-home dehumidifiers, the recommended replacement interval is every 12 months.

Collection tank

The water collection tank is a critical part that should never be allowed to overflow, lest it damage the entire unit and its surroundings.

✔ Periodically check the tank level indicator. This is ideally done each time before you switch on the dehumidifier. 

✔ If the unit doesn’t come with a tank level sensor, keep a schedule for emptying it.

✔ Whenever you empty the tank, inspect its slot area for signs of overflow or condensation. Wipe away moisture from the sensor and make sure the tank snaps securely back in place.

✔ For larger units that use a drain line, squeeze the tube every now and then to ensure it remains free of blockages or kinking.

Compressor

Larger dehumidifiers use a compressor to circulate refrigerant through the evaporator coils.

✔ For models that have an overload switch, this feature shuts down the compressor in case of overheating or low refrigerant levels. If the dehumidifier doesn’t function when turned on, check if the overload switch might have tripped.

✔ Frost buildup can cause overheating. Defrost the unit, and only reset the switch once the frost has melted.

✔ If the switch continues to trip after resetting, the unit may require a professional HVAC repair or replacement.

When addressing any issue with your dehumidifier, always refer to the manufacturer’s manual for specific guidance and safety information. Regular maintenance, such as cleaning filters and checking settings, can prevent many problems and extend the life of the unit. If the issue persists or involves mechanical or electrical components, it’s best to consult a professional technician.

At Total Home Supply, we offer a wide range of dehumidifiers, from portable models and crawlspace units to whole house dehumidifiers. We also carry dehumidifier parts and accessories, backed by excellent service and warranty!