How to check if AC is frozen?

Checking if your air conditioning system is frozen involves looking for distinct physical signs both inside your home and around the equipment components. The most definitive indicator is visible ice or a thick layer of white frost coating the copper refrigerant suction lines where they enter or exit the indoor air handler. If you safely remove the access panel of your indoor unit, you may directly see the evaporator coil encased in a solid block of ice rather than clean, metallic fins. Inside your living space, you will quickly notice that the air blowing from your supply registers feels completely warm or that the ambient temperature inside the house is steadily rising despite the thermostat calling for cooling. You might also hear strange bubbling, hissing, or cracking sounds emanating from the indoor unit as the system struggles and pressure shifts occur. Furthermore, excessive water pooling around the base of the indoor unit or overflowing from the condensate drain pan is a common warning sign, happening when accumulated ice melts and overwhelms the drainage system.