The answer to 'heat exchanger freezing up' is that a frozen heat exchanger is a common problem in HVAC systems, usually caused by issues with airflow, refrigerant levels, or a malfunctioning component. Symptoms include reduced heating or cooling, ice buildup, and strange noises. Solutions can involve cleaning the system, adjusting airflow, or repairing/replacing faulty parts.
In many cases, a frozen heat exchanger is a sign of a larger underlying issue that requires professional diagnosis and repair. While some basic troubleshooting and cleaning may be possible as a DIY task, it's generally best to call an HVAC technician to properly inspect and fix the problem to avoid further damage or safety risks.