What’s Causing My AC Unit to Freeze Up?

September 3, 2020

It might seem illogical to think that in Texas our AC units can freeze, however contrary to popular belief, they can. One of the first signs that your unit may be frozen over is that it begins to blow hot air through the vents. 

A few things that may help you determine if your AC unit is frozen or not working properly: 

  • Check the air filter to see if it is dirty
  • Check the coils for dirt
  • Look inside the unit for ice on the tubing
  • If there is ice, shut off the unit until it dries
  • See if the system runs normally
  • If it does not, contact a JD’s AC contractor

Know that even if you do not detect any visible ice, your HVAC unit may still be frozen. 

What are the common reasons that cause my AC unit to freeze up?

Blocked Airflow – Insufficient or a lack of airflow through the system is the number one leading cause of freezing HVAC units. When air is unable to move through the system, it cannot keep from condensation from building up inside on the evaporator coil. Blockages such as these that keep air from freely moving over the coil, causes it to become frigid and ice over. In most cases, the blocked airflow is caused by something as simple as a dirty air filter, or closed registers. To make sure that this isn’t an issue in the future, changing your air filters regularly (every month is average). As well as keeping your supply registers open while your AC unit is running. 

Low Refrigerant – Low refrigerant is usually a strong indicator of a leak in your system. This calls for a repair or replacement of your system – depending on the age of your system of course. When your air conditioning system is low on refrigerant it causes a large pressure drop in your system, which in turn causes the temperature to drop with it. When this happens, the evaporator coil becomes cold, and then freezes over. 

Faulty Thermostats – Faulty thermostats can cause the temperature to be misread and misadjusted this causing your AC unit to freeze as it tries to keep up with the adjustments. With not only causing your AC unit to freeze, malfunctioning thermostats also cause a large increase in your electrical bill. 

Drainage Issues – If you live in a humid climate such as Texas is, more times than not, a large amount of water vapor is turned into condensation. When your air conditioning unit is functioning properly, your air conditioning unit is to condense water vapor droplets into liquid as it travels through the units condensate lines and out of your drainage pipes. If the water becomes stagnant and get’s stuck in one place, it will freeze. 

What Should You Do When Your A/C Unit Freezes?

The first thing you should do after noticing your air conditioner has frozen is to turn it off and allow your HVAC unit to defrost completely. Once your AC unit has defrosted, clean or replace dirty air filters and remove any visible dirt or obstructions from your unit. In many cases, this may be all that’s required to fix the problem. However, some of the causes of a frozen air conditioner, such low refrigerant and faulty thermostats, will require assistance from a certified JD’s A/C HVAC specialist.

If your A/C unit continues freezing and you’d like to schedule a visit, call JD’s A/C today at (903)336-6041! One of our technicians would be happy to assist you and resolve any issue that you may have.

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