Why Is There Ice on My Air Conditioning Unit?

Even in tropical climates like Florida, ice can accumulate on and inside of an air conditioning unit. It’s quite the sight when your AC unit has ice on it in the middle of July. This icy display lets you know immediately that things are not right inside. Reviewing the causes will help you troubleshoot and get your AC unit back to keeping you cool where it matters most, inside your home.

How Does an Air Conditioner Freeze?

Ice can form on an air conditioner unit when the condenser evaporator coil’s temperature falls below freezing. This can happen when there is a low level of refrigerant, leakage, poor airflow, issues with the fan, or accumulated dirt on coils and filters. Ice can freeze inside the unit too. If you hear ice falling within the unit, call a technician as soon as possible.
As unusual as it looks, ice on an AC unit, or inside is a common problem. You may be able to fix the problem on your own without the help of a professional. It helps to catch the issue early, but many problems require an HVAC pro to fix.

What Are the Causes of Ice on an AC Unit?

Most issues with ice can be broken down into five areas:

  • Poor Air Flow
  • Low Refrigerant Levels
  • Broken Fan or Motor Problems
  • Dirt and Grime
  • Outside Temperature is Low

1. Poor Air Flow

Poor airflow as the cause for ice on your AC unit is usually a minor problem. Check the air filter; if it’s dirty, replace it. This may be all that’s needed to get your AC up and running again. After installing a new filter, let the ice melt and turn the AC on to test if a clean air filter does the trick. Check if the ice returns; if not, you’re good to go. Depending on how often you use your unit and where you live, changing the filter can also reduce dust build-up.

2. Refrigerant is Low

Another common problem for a freezing air conditioner is low refrigerant. When low, the AC unit will not be able to keep the evaporator coils within working ranges. Low refrigerant could signal a leak. Even by adding refrigerant, a slow leak could take weeks or months to reproduce the icy conditions. It will save time by calling an HVAC technician as soon as you notice ice and that refrigerants are at low levels. A qualified technician will be able to find and repair any leaks.

3. Broken Fan or Motor Problems

Sometimes an object can fall into an air conditioning unit and hit the AC fan, bending or breaking a fan blade. If you see ice on your air conditioner and hear unusual sounds coming from the unit, it could be a broken or bent fan. You can check for a broken fan blade, but the AC unit must be turned off before checking. Most fan motors are visible through the fan guard. If a broken fan is found, call your HVAC for a repair.

4. Dirt and Grime

Dirt, dust, and grime can affect how well an air conditioning unit works. Dirt can affect evaporator coils, condenser coils, and clogged air filters. Dirty evaporator coils cause ice to form because the coils can no longer absorb heat to lower the temperature. Getting the unit clean is no easy task and should be left to a professional HVAC repair technician.

5. Outside Temperature
If you run your AC unit when it’s below 50 degrees outside, you can run into ice forming on and in the unit. When outdoor temperatures drop, lubricant’s viscosity can increase and won’t flow as easily. Your system will work much harder to pump air conditioning refrigerant around the unit. If the refrigerant is at or below freezing, this can lead to an icy build-up on the evaporator coil.
At first signs of ice, turn the unit off and let the ice thaw on its own. Don’t try hacking away at ice as this can damage the unit. Don’t be tempted to let the unit run to keep your home cool. Greater damage can occur if you leave it running and could put your AC unit out of commission for longer.

Keep Your AC Unit Running Smooth

To prevent ice from forming again, ensure your AC unit regularly gets checkups and maintenance. Having a qualified HVAC technician on hand is the best move you can make for keeping your unit in top shape. If you’re in need of any cooling or heating services, schedule an appointment today.

Call Vredevoogd Heating & Cooling for all your Furnace & AC needs. In the Grand Rapids, Holland, Grand Haven Areas, Kalamazoo & Lansing areas call: 844-HVAC-365

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