Why do Evaporator Coils Freeze in an Air Conditioner?

Why do evaporator coils freeze in an air conditioner? The short answer is because the evaporator coil gets too cold reaching less than 32°F.? What would cause an evaporator coil to be so cold? The two common causes for that are either the coil cannot absorb enough heat, or the unit is low on refrigerant.

A coil is not absorbing enough heat could be the result of the following:

• Too little airflow, which can be caused by plugged filters, a blower or blower motor problem, or a ductwork restriction.
• The coil is plugged with dirt, which is usually a sign of deferred maintenance.

A unit that is low on charge will not have enough refrigerant flow to keep up with the compressor’s pumping capacity. That would cause the pressure in the evaporator to go too low as well. Low pressure produces low temperature when there is liquid refrigerant present. So, where the refrigerant enters the coil, it gets too cold, and it freezes the condensed water on the outside of the coil. The frozen area creeps across the coil and eventually can freeze the compressor in ice.

Another question that could be asked is “why do we care if the coil freezes?”. The obvious answer is that a frozen coil will no longer pass air so there will be no cooling delivered to the occupied space. In addition, when the coil thaws, it causes a water leak under the unit. The less obvious but probably more important reason to care is that the system needs to absorb heat in the evaporator to vaporize the liquid refrigerant. A frozen coil cannot do this.? Because of that, liquid refrigerant can enter the compressor. This is one of the more common reasons for compressor failure.? Replacing compressors are among the more expensive service tasks and the unit will be non-functional for a while. Failed compressors are among the most common reasons units are replaced on an emergency basis.

Changing filters and checking the condition of the blower regularly is the way to prevent frozen evaporator coils.

To learn more, reach out to #HeliosServicePartners through DM or email [email protected]. We would love help you ensure your equipment is running at peak performance. https://heliosservicepartners.com/your-partner

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Written by Dale Rossi

Technical Support Service Manager

https://www.dhirubhai.net/in/dale-rossi-9374a610/