The answer to 'why is my boiler blowing cold air' is that there are several common causes, including a malfunctioning thermostat, low water pressure, or a problem with the boiler's heating element. If your boiler is blowing cold air, it typically indicates an issue with the heating system that requires troubleshooting and repair.
Some common symptoms of a boiler blowing cold air include the house feeling colder than the thermostat setting, the boiler running but not producing heat, or the radiators or baseboards feeling cold. Solutions can range from simple DIY fixes like adjusting the thermostat or bleeding the radiators, to more complex issues that require a professional HVAC technician to diagnose and repair, such as a broken heating element or a leak in the system.