2 Possible Reasons Why The Evaporator Coil In Your Central A/C Unit Keeps Freezing Up

25 March 2022
 Categories: , Blog


After noticing that the air in your home feels warm and muggy, you may have discovered that your home's central A/C unit has frozen up. After unplugging and while thawing the unit, you may have noticed that the evaporator coil is the source of the ice.

Since it is possible that the coils freezing up was a one-off occurrence, wait until the unit is completely dethawed. Then, run it as normal and keep an eye on the coils for any ice formation after a few hours. If you do find that ice keeps forming on the evaporator coils, there are a couple of possible reasons why the problem keeps happening.

1.  Airflow Through the System Has Been Greatly Reduced

One major cause of ice formation on a central air conditioner's evaporator coil is reduced airflow. As part of its job, the surface of the coil cools the air and removes moisture before it is delivered to your home. 

If the air is not flowing freely, the coil will keep processing the same air, which can lead to ice formation. You can try changing the filter and cleaning the vents. But, if this does not work, the fan may be malfunctioning, which will need to be fixed by an HVAC repair technician.

2.  Leak within the Unit Is Coating the Coil with Coolant 

Another possible cause of a constantly frozen evaporator coil is a coolant leak within the A/C unit. To condition the air passing around it, the surface of the evaporator coil must remain clean and clear of any contaminants.

However, if coolant is leaking onto the surface, it will coat the coil where it will freeze on contact. Since a coolant leak will affect not only the evaporator coil but will also affect the condenser, you should have the leak fixed and the coolant recharged by a certified professional.

When the evaporator coil keeps freezing up, the air conditioner will be unable to adequately cool your home or remove humidity from the air. If you have tried cleaning the vents and replacing the filter only to have the coil refreeze, the problem may lie with a broken fan or coolant leak, which needs to be fixed by a professional. Contact an air conditioning repair service if you believe one of these is causing the issue to set up a service call to have someone diagnose and fix the problem.

To learn more, call a company like Willman Air.