Air Conditioning

Why Your A/C Freezes in the Summer

Why Your A/C Freezes in the Summer

While ice on a hot summer day is usually a welcome sight, an A/C freeze isn’t. Ice formation on the indoor evaporator coil of your central air conditioner can eventually turn into a solid block, obstructing all airflow through the system. This can seriously damage expensive components such as the compressor. Since the evaporator coil is sealed inside the indoor air handler, you're usually unaware that ice is accumulating. The only noticeable signs may be warm air blowing from the A/C vents, automatic system shutdowns for no apparent reason, or water pooling on the floor around the air handler when the ice melts.Here are some common causes of an A/C freeze and what may be required to resolve them:

Dirty Air Filter

As the air filter clogs, system airflow is strangled. Low airflow through the evaporator coil reduces heat extraction and causes the coil temperature to drop from normal approximately 40 degrees to below freezing. Condensation on the coil then freezes and ice accumulation begins. To prevent low airflow, replace the filter monthly during the cooling season.

Insufficient Refrigerant

When refrigerant pressure in the system drops too low, the refrigerant vapor expands excessively and actually becomes colder. This, in turn, causes the evaporator coil temperature to drop below freezing and ice to form. Low refrigerant charge is usually traceable to a leak in the system that must be pinpointed and repaired by a qualified HVAC service tech. When the refrigerant charge is returned to specs, coil temperature should stay above freezing.

Dirty Coil

Dust and dirt particulates in the system airflow gradually accumulate on the coil. This inhibits heat extraction, allowing the coil temperature to fall below 32 degrees and ice formation to begin. Since the coil is mounted inside the air handler, it’s not accessible for DIY cleaning. Coil cleaning should be performed by a qualified professional. It’s also a standard part of regular annual preventive maintenance offered by your HVAC contractor.Don't suffer due to an A/C freeze on a hot summer's day. Contact Air Assurance for fast professional service.

Our goal is to help educate our customers in the Tulsa and Broken Arrow, Oklahoma area about energy and home comfort issues (specific to HVAC systems). For more information about other HVAC topics, call us at 918-217-8273.