The answer to 'boiler blowing hot air' is that the boiler is likely overheating and needs to be inspected and repaired. This can be caused by a variety of issues, such as a malfunctioning thermostat, a problem with the pressure relief valve, or a buildup of sediment in the boiler. If the boiler is blowing hot air, it's important to shut it off and call a professional HVAC technician to diagnose and fix the problem.
Trying to repair the boiler yourself can be dangerous if you don't have the proper training and experience. HVAC systems can be complex, and making mistakes can lead to further damage or even safety hazards. It's generally best to leave boiler repairs to the professionals, who have the tools, knowledge, and expertise to diagnose and fix the issue safely and effectively.