Why Your AC Coil Freezes and How to Fix It

If your home uses a heat pump or air conditioning system to keep spaces cool in the summer, you could experience a common problem: frozen evaporator coils. These systems use refrigerant to remove heat from indoor air, so ice can form if something goes wrong with the heat transfer. So, why does an AC coil freeze up exactly?

Parker Heating & Air proudly offers top-tier AC services in Heritage Hills, CO, including air conditioning repair for frozen coils. Our technicians have ample experience dealing with this problem. Below, we explain what causes frozen air conditioning coils and what you can do to resolve the issue. 

What Makes Frost Form on Air Conditioner Coils in Heritage Hills

You might assume it’s acceptable for parts within a Heritage Hills cooling system to have frost or ice, but you’d be mistaken. Why does an AC coil freeze up? Here are the top reasons:

Low Refrigerant Levels

Evaporator coils are within the indoor portion of a cooling system, and the outdoor unit houses the condenser coils. Refrigerant flows through both components in a closed, continuous loop to draw heat from indoor air and disperse it outdoors. Because refrigerant moves in a closed loop, a leak could drop the chemical’s levels, reduce its ability to absorb heat and cause ice to form on the coils.

Restricted Airflow in AC Unit

Cooling systems need sufficient airflow to efficiently transfer heat. Dirty HVAC filters and blocked AC vents restrict airflow, causing the equipment to work harder. 

Unfortunately, this excessive operation causes several issues, including skyrocketing energy bills and premature wear and tear of HVAC components. It can also cause dirt and debris to collect on the coils. When this happens, they can’t absorb heat correctly, which triggers ice buildup.

Broken Thermostat

Sometimes, cooling problems stem from the thermostat and not the HVAC system. If you see frozen coils in the morning, it could be due to a thermostat malfunction. The device might fail to trigger the cooling unit to shut down at night when temperatures drop in Heritage Hills.

Faulty Blower Fan Motor

The blower fan motor operates the fan that blows air over the evaporator coil. If the fan or motor fails, it could restrict airflow from the cooling system and cause ice to form. Warning signs of a failing blower motor include strange noises and warm air coming from the vents.

AC Coil Troubleshooting Tips

Now you know the answer to the question, “Why does my AC coil freeze up?” If this problem occurs in your Heritage Hills property, you can take the following steps to address it.

Turn Off the Cooling System

If you suspect your cooling system components have an icing problem, do not continue running your system. Shut it off immediately by setting the thermostat to “Off” instead of “Cool.” 

If you have a heat pump, your thermostat might have a “Defrost” mode. Don’t turn on this setting unless you have a frozen condenser coil; it only works for the outdoor unit.

Let the Coils Defrost Naturally

Allow the coils to thaw naturally. Don’t use anything to break the ice off because you could accidentally damage the component and cause a refrigerant leak. Instead, you can set the HVAC fan to “Auto” to blow room-temperature air through the system to thaw everything faster. 

Replace the HVAC Filter

Check your air filter. Is it clogged? If so, it likely caused the icing, so replace it while the equipment thaws naturally.

Contact a Local HVAC Technician

Problems with dirty coils, refrigerant leaks, and blower motor damage require the expertise of a Heritage Hills HVAC company. These professionals have the expertise necessary to thoroughly inspect the cooling unit, identify the reason for the frozen coils, and implement the problem’s best solution.

Common Signs of AC Coil Freezing

An obvious sign of frozen evaporator coils is visible frost or ice. Yet the system may display other warnings indicating a serious issue, including:

• Water puddles near the drain pan
• Lack of cool air from the vents
• Cooling system blowing warm air