Believe it or not, the evaporator coils inside the AHU (Air Handling Unit) are freezing. You may notice the refrigerant lines on the condenser or at the AHU are frozen with ice build-up. The frost or ice builds up on the evaporator coils and blocks air flow (low air flow and no cooling are a sign of a low charge). A low refrigerant charge will cause the evaporator coil to operate at or below freezing. Since the coil typically operates below the dew point, it draws condensation out of the air. When the evaporator coil begins operating below freezing all this condensation freezes to the evaporator coil and the unit stops cooling.
Repairs—If something appears to be not working right with your heating and cooling, a professional will examine the whole health of your system. It’s easy to hop on the internet and research information to find our own conclusions, but there could be an additional component or reason why your system isn’t working properly that isn’t clear or recognizable. Consider our own health concerns—you might check out your symptoms online to try and draw your conclusions, but it’s always best to make an appointment with a doctor to receive an expert opinion.