Why Do AC Coils Freeze

Why do AC coils freeze? This is a more common problem than most people think, usually caused by a malfunctioning system or a lack of maintenance. Our professionals offering AC services in Indianapolis, IN, can investigate and track down the underlying issue. 

Learn more about common causes of a frozen evaporator coil and why coil maintenance can help. 

1. A Dirty Air Filter Causes Restricted Airflow

Replacing or cleaning the system’s air filter is one of the most important air conditioning maintenance steps you can follow. A dirty air filter blocks air from moving freely through the system. With low airflow, the refrigerant cannot work as efficiently as it should, causing the icy buildup.

Pollen levels in the Indianapolis, IN, area are highest in spring and summer. Extra pollen in the air can cause the filter to clog faster than normal. Instead of cleaning or replacing it every three months, you might need to replace it every two months when the air quality is lower.

2. You Have a Refrigerant Leak at Your Indianapolis, IN, Home

Why do AC coils freeze, and do low refrigerant levels cause this issue? Low refrigerant can be a significant problem. When levels are low, the system struggles to pull heat from the house through the metal coils.

Service technicians can measure the level of refrigerant in the system. If they find something wrong, they will patch any leaks before topping off the coolant.

Indianapolis, IN, follows federal regulations for adding refrigerant to an air conditioning system. Only a licensed technician may add refrigerant to your system. You cannot do this job yourself.

3. Remove Clogs From the Condensate Drain

The air conditioning system uses a condensate drain line to allow condensation and moisture to flow away from the system. Removing this moisture is important for preventing corrosion of the system.

If the drain line is blocked, the water might back up and cause the system to run poorly, leading to frost buildup. Maintenance technicians can clear the line for you.

4. Frozen AC Coils May Occur If Your Return Vents Are Blocked

If you notice frozen coils on your air conditioner, check the return vents inside your home. Perhaps someone put furniture or boxes over the top of the return vents, blocking the movement of air. Coils can freeze when air doesn’t move through the system properly.

Indianapolis, IN, has hot, humid summers with temperatures in the upper 80s and 90s from June through early September. When your air conditioner cannot generate proper airflow because of blocked return vents, the system struggles to remove humidity on hot days. This can lead to frozen air conditioning coils.

5. You Might Have Dirty Coils

Why do AC coils freeze, and can cleaning them fix the issue? Coils can develop frost because of grime and dust on the metal coils. The dust prevents the coils from absorbing and dispersing heat efficiently, leading to icy buildup on the metal.

Air conditioning technicians can clean your coils as part of an annual maintenance visit.

6. Your Thermostat Is Not Functioning Properly

A thermostat malfunction can lead to frozen air conditioning coils. Perhaps your thermostat is not accurately measuring the indoor temperature. Because of this error, it might signal to the air conditioner that it needs to keep running.

An air conditioning system running more than it needs to often leads to an icy buildup on the coils.

7. The System’s Blower Fan Is Failing

When the system’s blower fan is not moving enough air, icy buildup on the coils is possible. A failing fan delivers weakened airflow. You might need repair technicians to inspect this vital component and repair or replace it to restore normal airflow to the system.