The answer to 'why is my air handler blowing hot air' is that there could be several common causes, including a problem with the thermostat, a malfunctioning compressor, or an issue with the air handler itself. Symptoms may include the air handler continuing to blow hot air even when the thermostat is set to cool, or the air handler not turning on at all.
Some potential solutions include checking the thermostat settings, inspecting the air filters, and ensuring the compressor is functioning properly. However, it's important to note that air handler issues can be complex and may require the expertise of a professional HVAC technician, especially if the problem persists or you're uncomfortable troubleshooting the system yourself.