Why is My Dehumidifier Freezing Up and How to Prevent It

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When you live in an area with high humidity, there’s not a whole lot that’s more frustrating than your dehumidifier freezing up and not working. Why in the world does this happen and what can you do to stop it? Excessive humidity in your home can cause damage to your furniture, cause dampness, cause mold to grow, and have a negative impact on small children and even adults who have health conditions.

This is why it’s critical that you make sure your dehumidifier functions properly at all times, so that it works when you need it to get the excess moisture out of your home.

What causes ice on dehumidifier?

There are lots of different factors that come into play. However, narrowing it down and taking a closer look at your personal environment can help you figure out what is going on.

Temperature of the room

One of the most common causes of a dehumidifier freezing up is the temperature of the room that it is located in. Most units will work perfectly fine in a room that is 65° F or more. However, if the air temperature drops lower than that, the unit may freeze up and quit working.

The air is pulled into the unit through a vent. As it travels through, the cold metal coils cause the water in the air to condense and drop into a collection reservoir or pumped out through a hose. This works quite well when the temperature is high, but if it gets too cold, the water vapor will freeze instead of condense, which causes problems.

Flow of air

Another reason your dehumidifier could freeze up is the flow of air through the unit itself. If your fan is not turning well or the condenser is blocked, this keeps the air from flowing through the unit quickly enough. If you are having your unit regularly and properly maintained, you will find these issues right away, and you can clean the part or replace it as necessary.

If you have a dehumidifier that is icing up, you need to stop using it. If you keep using it while the coils are frozen over, you could cause further damage. The motor/compressor unit will have to work that much harder and could end up getting overwhelmed and burning out.

If you believe your dehumidifier is not working like it should, perhaps the unit is making more noise than it should and/or the humidity levels are beginning to rise, disconnect it and see if there is any maintenance that needs to be done on it.

How can you prevent your dehumidifier from freezing up?

There are several things that you can do to keep your dehumidifier from freezing up—and defrost it when it does.

Humidity controls

If you have a dehumidifier and the coils are freezing up, but the temperature of the room is higher than 65°, you may have a problem with the humidity control. This control, known as the humidistat, is a lot like a thermostat in that it monitors the level of humidity in the room. The electrical contacts of the humidistat cause the compressor of your dehumidifier to turn on. If the humidistat is not functioning properly, your compressor stays on, which causes the coils to freeze up.

In addition, the electrical contacts can end up getting welded shut, which leads to the same issue. In order to troubleshoot your humidistat, you’ll want to first disconnect the power to your unit. Then, turn your humidistat dial and listen for the clicking noise that indicates it is functioning properly. In addition, you can test the humidistat using a multi-meter. Remember that when you are rotating the control, the contacts need to be open circuit. If they are not, you’ll need to replace it.

Blower wheel/fan blade

If the coils in your dehumidifier are freezing up, but the temperature in the room is over 65°, you may have a problem with your blower wheel/fan blade. These 2 parts control the flow of air that is required to prevent the condenser coils from freezing up. If you have cleaned the air filter, but there is no air flowing through the grill, you can remove the fan cover so that you can inspect the coils.

Take the time to clean off any dirt/debris that could be preventing air flow. Then, check the fan blade/blower wheel to make sure that there’s nothing in the way. If they appear to be damaged, you’ll want to replace them. If not, take the time to carefully clean them. You’ll want to manually move the fan motor to make sure that it does move before you power the unit on.

Fan motor

If the coils on your dehumidifier are freezing up and the temperature in the room is more than 65°, the issue may be the fan motor. This part of your dehumidifier keeps the air flowing freely so that the condenser coils don’t freeze up. If you want to troubleshoot your fan motor, you’ll need to check the grille for air flow and make sure that the air filter isn’t clogged with dirt/debris. Remove the fan cover and look for any indications of damage.

You should take this time to clean the parts that are dirty and make sure the motor is moving freely, with no blockages. Turn your unit to fan mode and pay attention to the operation of the fan. Be careful when you do this. If the fan is not spinning or is slowly spinning, you’ll need to replace it.

1 thought on “Why is My Dehumidifier Freezing Up and How to Prevent It”

  1. Floyd Arthur Miller

    The room temp. is 68deg. , the fan is running on high and working fine. I shut it off and let it defrost for 2 days and it worked for a day and froze up again. It never stops running. Thank you!

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