The answer to 'why is my air handler blowing cold air' is that there could be several common causes, such as a problem with the thermostat, a refrigerant leak, or a malfunctioning compressor. The air handler is the indoor unit of your HVAC system that circulates the cooled air throughout your home, so if it's blowing cold air when it shouldn't be, it indicates an issue with the cooling system.
Some common symptoms include the air handler running constantly, the air feeling too cold, or the home not reaching the desired temperature. Potential solutions could be adjusting the thermostat, checking for refrigerant leaks, or troubleshooting the compressor. However, many of these repairs should be handled by a professional HVAC technician, as they require specialized knowledge and equipment.