A/C freezing problems are the root cause of many summertime service calls by Edwardsville, IL, HVAC technicians. When an AC unit “freezes up,” it limits or even halts the HVAC system’s ability to cool the home. You may notice the evaporator coil takes on a frosty or frozen appearance, and your unit starts blowing hot air. Trane, the manufacturer of many HVAC systems, says there are a few reasons for this common A/C problem. 
Airflow Blockage
Closed air supply registers and dirty air filters are common causes of airflow blockages that result in A/C freezing problems. In order for the evaporator coil to work efficiently, airflow should be unrestricted; this keeps condensation from building up, freezing, and causing your unit to malfunction. Prevent this from happening by keeping your supply registers in their open position and changing your air filter at least monthly.Problems with Drainage
When the weather is humid, there is more condensation of water vapor within your A/C unit. Normally, the unit condenses the vapor, forming a liquid that makes its way through the lines in the unit and exits via a drain pipe. Anything blocking the lines running to this pipe can cause water to remain stuck inside and result in a frozen unit.Issues with the Thermostat
Setting the thermostat too low can force your A/C unit to run continually, and the effect of this is that the condenser’s temperature drops below the freezing point. This can also happen as a result of a faulty thermostat. Either way, the unit freezes over, and you’re stuck waiting for a fix (or a thaw).
