Every summer we get numerous service calls related to “no cooling” problems. Many of those issues are due to freeze up of the evaporator coil. When a system has an icing problem it could mean that the coil, suction line (thick copper line from coil to compressor) or compressor are encapsulated with ice. Once the evaporator coil is covered with ice then all noticeable cooling stops because you no longer get any airflow through the floor registers. That is usually the time when customers call for service. The best advice at that point is to turn the A/C off and turn the furnace fan to “On”. This will expedite the thawing out process.
There are many possible causes for icing, but the following list are the most common:
- Dirty furnace filter
- Dirty or plugged evaporator coil
- Dirty condenser
- Defective furnace blower motor
- Refrigerant leak
- Faulty expansion valve
- Blocked return air vents
A regular maintenance inspection of your air conditioning equipment can prevent many of these things from developing into a major problem.