The answer to 'heat exchanger not working' is that the heat exchanger is a critical component of your HVAC system that can fail, leading to a lack of heating. Common causes include wear and tear, corrosion, cracks or holes, and issues with the blower motor or airflow. Symptoms may include cold air blowing, strange noises, or carbon monoxide leaks.
In many cases, a faulty heat exchanger will require professional repair or replacement. Attempting to DIY this repair is not recommended, as it can be dangerous if not done properly. It's best to call an HVAC technician to diagnose and fix the issue to ensure your safety and the proper functioning of your system.