Dehumidifier Not Working? 5 Common Causes & Easy DIY Fixes

Is your dehumidifier freezing up or has the fan stopped spinning? Discover the top 5 reasons your dehumidifier isn’t collecting water and how to fix it yourself. From faulty fan motors and blower wheels to frozen coils and Frigidaire F0 errors, learn how to diagnose and repair your dehumidifier with our step-by-step guide.

How does a dehumidifier work?

Basically a fan draws humid, warm air over a cold coil. The cold coil then condenses the moisture into a liquid. The water is removed via a drain pipe. Next, the dry air passes over a warm coil and then added back into the room.

A dehumidifier is an important part of your air conditioning system, especially if you live in a climate with high humidity during the summer. The unit will ensure the air that comes into your HVAC system isn’t too moist. When this occurs it can lead to erosion of parts and mildew and mold problems.

People tend to feel uncomfortable and find it harder to breathe in humid conditions. The relative humidity should be between 30 and 50 percent in a room that is 68 degrees. When it’s higher than that, you start to feel sticky. A dehumidifier replaces that humid area with cooler, dryer air. 

Common Issues and Solutions: dehumidifier not working

Defective Bucket Switch

The bucket switch is a single pole, double throw (SPDT) device that tells your dehumidifier to shut off when the water collection bucket is full.

The bucket switch is activated by a float that’s mounted inside the bucket. The switch is then mounted directly to the dehumidifier frame behind the bucket.

Sometimes the bucket switch can fail. When this occurs it makes the machine think the bucket is full, when in reality it is not.

In the event this happens, you’ll want to check each component that works with the bucket switch. Here’s how to check each part:

To Remove the Float

1. Disconnect the dehumidifier from the power supply
2. Remove the bucket
3. Drain any condensate that may be present in the bucket
4. Remove the pin that holds the float to the bucket
5. Remove the float through the access hole at the top of the bucket

To Remove the Bucket Switch

1. Disconnect the dehumidifier from the power supply
2. Remove the three electrical leads from the terminals on the bucket switch
3. Squeeze the tabs together and push up on the switch from the bottom

How to Test the Bucket Switch

1. Test the resistance present between the three terminals on the switch
2. Use a multi-meter on the resistance scale setting
3. The switch should be on “AT REST” position
4. Resistance readings should be:
   1. Common – Normally Open = MAX resistance
   2. Common – Normally Closed = ZERO resistance
5. If you have the switch arm DEPRESSED, readings will look like this:
   1. Common – Normally Open = ZERO resistance
   2. Common – Normally Closed = MAX resistance
6. If your readings are not within these ranges you’ll want to replace the bucket switch.

Failed Humidity Sensor/ Humidistat

About this: One of the most crucial components of a dehumidifier is the humidity sensor. As the name suggests, this component measures the air’s humidity levels. The appliance will use that sensor’s data to decide whether it should turn on the fan.

For example, when the humidity levels are too high, the dehumidifier will turn on its fan to draw more air inside. Conversely, it’ll shut the fan off when the sensor finds that humidity levels are already low enough.

This part is made up of two components – a relay amplifier and a sensing element.

The sensing element features two alternate metal conductors, and when there are changes to relative humidity, it will cause electrical resistance between the conductors.

The relay amplifier measures the resistance created and sends a signal to the dehumidifier to turn on or off.

The humidistat works by monitoring the levels of moisture present in the air. When moisture levels get too high, the contacts close and allow the humidifier to turn on.

When the humidistat fails, the dehumidifier cannot run.

There are several things you should do to troubleshoot this issue:

1. Is your dehumidifier set for a humidity level lower than the room?
2. Check to see if the humidistat is properly lined up, and not touching a wet condenser or surrounded by damp air due to a dirty air filter.
3. Does it have a refrigerant leak?
4. Does it shut off periodically? It may be overheating and turning off. If so, try to conduct a power cycle.
5. Check to see if the humidstat is encased in ice or dirt. Try to clean the humidistat and the filter to see if that fixes your problem.
6. Use a multi-meter to test for the part for continuity. If there is none, replace the part.

Failed compressor capacitor

The capacitor helps the compressor run. When you find that your dehumidifier is running and both exhaust/intake fans are running, it’s a good sign that the capacitor for the compressor is bad.

You may also notice that water is not being collected from the air, or the overload device keeps tripping. If the capacitor fails it will prevent the compressor from rotating the refrigerant.

One of the most common reasons this part fails is the compressor grill/air vent is covered with dust and dirt that’s been collected over time. There are several other reasons it can fail, including:

Failed overload device – This component keeps the motor from becoming damaged.

Faulty fan motor – The fan should spin freely, allowing ample airflow through the device. If the fan is barely moving or humming, it needs to be checked and possibly replaced. 

Electronic Control Board – The control board tells the compressor when to start. If there is a problem with this part the compressor will not be able to start.

The easiest way to troubleshoot this problem is to test for continuity with a multi-meter. If you find there is none, you’ll need to replace the part.

Compressor overload protection defective

If the compressor is not working on your dehumidifier, and you’ve already checked the capacitor, the next step you should take is checking the overload protection.

Much like a thermal fuse on a dryer, dehumidifiers have what are called overload protection devices.

The overload protector is attached to the compressor, and works to detect excessive current overload or heat.

If the overload is actuated, the compressor will shut down, and automatically reset itself after it cools down.

The compressor will try to start after the cool down period.

The overload protector is found under the terminal cover. Here’s an easy way to gain access to this part:

1. Disconnect the power
2. Remove the terminal cover

To test for an overload, follow these steps:

1. Disconnect the power
2. Remove wrapper
3. Remove Terminal cover
4. Disconnect all wiring, and check the overload terminals using a multi-meter
5. Be sure the overload is at room temperature when you attempt to check it
6. It should read ZERO ohms. Any other reading signals this part needs to be replaced.

Here are some common reasons compressors overload:

1. Low Voltage – Disconnect the machine and check the voltage going to your electrical outlet and the dehumidifier itself.
2. Defective run capacitor (as discussed above)
3. Dirty condenser or evaporator
4. Insufficient amounts of air passing over the condenser

Evaporator fan motor not working

If your dehumidifier is not collecting water, and you have already verified that the ambient temperatures is above 65 degrees Fahrenheit, you may be dealing with a faulty fan motor. Without sufficient airflow over the evaporator coils, the unit cannot pull moisture and will develop a layer of ice or frost. You can check this seeing how much air is coming through the grill.

Troubleshooting Steps:

• Check the Filter: If you feel weak airflow, start by cleaning the air filter. A clogged filter is the most common cause of restricted air.
• Inspect Coils and Fan: Remove the cover and clear any dirt or lint from the coils. Ensure the fan blade or blower wheel is still securely fastened to the motor shaft.
• Test Mechanical Movement: Spin the fan manually to see if it rotates freely. If it feels stuck or gritty, the bearings have likely failed.
• Observe “Fan Only” Mode: Turn the unit on to the “fan only” setting. If the motor hums, spins slowly, or stays stationary, it is likely defective and needs replacement.
• Electrical Testing: If the motor is silent and motionless, use a multimeter to check for continuity. If there is no power reaching the motor or the windings are open, the part must be replaced.

Loose Or Damaged Wires

About this: The fan inside your dehumidifier is powered by a fan motor. That motor is electrically powered, which means it has wiring connecting it to the appliance’s control board and power supply.

The wires must be connected firmly on both sides to ensure that power can flow as needed to the fan.

What’s happened: Assuming the fan is in good working condition, another problem that can prevent it from working is loose or damaged wires.

Remember: each wire has two connections: one at the fan motor and the other at the control board or power source inside the dehumidifier.

The wires could become loose if they weren’t attached firmly in the first place. Besides that, the vibrations from the dehumidifier’s operation can also cause them to become loose over an extended period.

However, electrical faults like power surges and short circuits can cause the wires to overheat and burn. That will also prevent the fan from working.

How to fix it: Firstly, you’ll have to inspect all wiring that connects the fan to the rest of the dehumidifier. The wires must be attached firmly on both ends and be free from damage.

Any wires that are burned, torn, ripped, or have holes in them must be replaced with new ones. Damaged wires are no longer safe or reliable for use in your dehumidifier.

Purchase a Dehumidifier for your Kid’s Dorm Room– recommended!

If your son/daughter is headed off to a dorm anywhere in the southern half of the country, or anywhere especially humid, I highly recommend getting a dehumidifier for their dorm room. With all of the extra bodies in a dorm, and the extra showers and laundry that come with all those students, dorms can get very stuffy. The higher the dorm room is situated (like my daughter on the 7th floor!), the more likely the room will be hot and muggy.

Without proper ventilation, kids in dorms can become sick often. Issues like mold and mildew will settle into the rooms, causing allergies and respiratory illnesses all year round. My daughter suffers from allergies without the help of humid dorm room. We purchased a simple dehumidifier on Amazon to help purify the air in her dorm room and make it more bearable.

Modern dehumidifiers come with all sorts of helpful and smart features. I recommend something similar to the one we purchased. It has a nice, quiet mode. Also look for a large capacity water tank so you don’t need to empty it quite as often.

They come in a variety of price ranges, but I recommend a reasonable investment up front. It can be used for the duration of their college years and will likely last without incident. You’ll find the $70 investment well worth the health of your family.

Note: we may receive a small commission from your purchase, at no additional cost to you.

Troubleshooting the F0 Error Code on Frigidaire Dehumidifier

The Frigidaire F0 error code is a communication signal indicating a potential issue with the internal sensors, humidistat, or compressor. While often related to low refrigerant or a faulty control component, it can sometimes be triggered by external factors like extreme room temperatures or improper power supply.

Troubleshooting the F0 Error Code

• Check Power Source: Avoid using extension cords or power strips. Plug the dehumidifier directly into a wall outlet to ensure it receives consistent voltage.
• Verify Room Temperature: Ensure the ambient air is between 41°F and 90°F. Operating outside this range can cause the refrigeration system to malfunction and trigger the code.
• Perform a Hard Reset: Unplug the unit for five minutes to allow the internal capacitors to discharge, then plug it back in. This simple step often clears temporary software glitches.
• Inspect for Freezing: Heavy frost on the coils can trip the F0 code. If ice is present, turn the unit off and let it thaw completely before restarting.
• Test the Humidistat: If the error persists after a reset, the humidistat may have lost continuity. You can use a multimeter to test the part; if it fails, it will need to be replaced by an authorized technician.
• Professional Recharge: In some cases, F0 indicates low refrigerant. Because refrigerants are highly regulated, this requires a certified service center to diagnose and recharge the system.

Dehumidifier Freezing Up

A dehumidifier that develops ice on its coils is usually suffering from poor airflow or environmental conditions that are too cold for its refrigerant system. Most residential units are designed to operate between 70°F and 90°F; when the intake air is too chilly, moisture freezes onto the coils instead of simply condensing into the reservoir. To fix a frozen unit, turn it off to let the ice melt naturally and look into these causes:

• Ambient Temperature: Refrigerant-based models often struggle in rooms below 60°F. If using the unit in a basement or during winter, ensure the space is sufficiently heated.

• Dirty Air Filter: A clogged filter restricts the warm air needed to keep internal components at the proper temperature, leading to rapid ice buildup.

• Faulty Fan Motor: If the fan isn’t spinning at full speed, cold air remains trapped inside the machine, causing the coils to drop below freezing. Remove dirt and debris blocking the fan blades.

• Low Refrigerant: A leak in the sealed system can cause the remaining refrigerant to expand too much, making the coils exceptionally cold and prone to icing.

Why Is My Dehumidifier So Loud?

While some humming is normal, excessive noise from a dehumidifier is usually a sign of mechanical wear or loose components vibrating. Sounds like grinding, rattling, or loud buzzing indicate that internal parts need attention.

• Loose Mounting Screws: Constant vibration can loosen the screws holding the outer cabinet or internal components. Tightening these fasteners often eliminates rattling or buzzing sounds.
• Unlevel Surface: If the unit isn’t sitting perfectly level on the floor, the internal weight distribution becomes uneven, leading to increased vibration and localized rattling.

Blower Wheel Problems:

The blower wheel is a cylindrical fan that draws air into the dehumidifier to remove moisture. It activates whenever humidity levels rise, but it can become a significant source of noise if it becomes loose, misaligned, or improperly installed.

• The Issue: A misaligned wheel will grind against the internal housing, creating a loud rubbing or scraping sound.
• The Fix: Detach and reinstall the wheel, ensuring it is centered and secure but not overtightened.
• Maintenance: Always spin the wheel manually after reinstallation to check for clearance. If the fins are physically worn or warped from previous grinding, the wheel should be replaced to prevent future motor strain.

Fan Blades and Motor Bearings

Dirty or Obstructed Fan Blades: Dust buildup or small debris caught in the fan housing can cause a rhythmic clicking or high-pitched whirring. Cleaning the blades ensures smooth rotation and reduces air resistance.

Worn Fan Motor Bearings: If the unit produces a persistent grinding or squealing noise, the fan motor bearings are likely failing. In most cases, this requires replacing the motor assembly.

Faulty Compressor

Vibrating Compressor: The compressor sits on rubber mounting pads to dampen sound. If these pads harden or perish over time, the compressor will vibrate directly against the metal frame, causing a deep, loud drone.

About this: There are two types of compressors: the ones that use desiccants to remove moisture from the air and the ones that rely on circulating refrigerant instead.

The refrigerant-based dehumidifier has a compressor inside the unit. Its job is to circulate the refrigerant through coils so they become cold and can dehumidify the air that passes through.

Are Desiccant Dehumidifiers Quiet?

Yes, desiccant dehumidifiers are very quiet. While they might use fans, they do not have a compressor or a sealed cooling system that makes a lot of noise.

Frequently Asked Questions

Should I Run A Dehumidifier Fan On Low Or High?

You should run the dehumidifier fan on high if you need the appliance to quickly remove moisture from the air. However, putting it on low is enough if you’re using it to maintain humidity levels.

What Refrigerant Is Used In Dehumidifiers?

Dehumidifiers typically use R-410A refrigerants. However, some older models might still use R-407C. Modern dehumidifiers do not use Freon.

Why does my dehumidifier keep shutting off?

It could be that the sensor isn’t ready the humidity level properly. Humidity starts setting in the unit.

This will lead to the machine shutting down before reaching the right moisture level in the air. A dehumidifier that also has a thermistor that works paired with the sensor could have a faulty thermistor too. 

Is It Worth Replacing A Dehumidifier Compressor?

That depends. Some dehumidifier compressors might still be under warranty, so you can get them replaced for free. However, it’ll likely take some time to get a replacement. However, if your dehumidifier is old or the compressor costs too much, you’re better off buying a new dehumidifier.

Compressors don’t fail so often or so quickly. But when they do, they can get very loud and noisy and will likely require a replacement.

How to fix it: Firstly, remember that the compressor is part of the dehumidifier’s sealed system. The system is sealed to ensure that refrigerant can circulate without leaking into the surrounding environment, which isn’t good.

As such, only technicians certified by the U.S. Environmental Protection Agency (EPA) can troubleshoot, repair, or replace it.

Can you recharge a dehumidifier?

Yes, you can add coolant or refrigerate to recharge a humidifier. One of the problems the f0 code may be indicating is the machine is low on refrigerate. This is like adding the product to a refrigerator or air conditioning unit.

The only problem is that refrigerates like freon are highly regulated so they are hard to get. They are also expensive. You will need an Authorized Frigidaire Service Center to do the recharge.