What is typically the main concern with rooftop package units regarding the heat exchanger?

The main concern with rooftop package units regarding the heat exchanger is safety. The heat exchanger plays a critical role in the operation of HVAC systems by transferring heat between the air and the refrigerant without mixing the two. If there are any faults or cracks in the heat exchanger, it can lead to the leakage of combustion byproducts, including carbon monoxide, into the building's air supply. This presents a serious health and safety risk to occupants.

Additionally, maintaining the integrity of the heat exchanger is vital for preventing hazardous situations that could arise from gas leaks or overheating. Regular inspections and maintenance are essential to ensure the safety of the system and the environment it operates within.

While efficiency, cost, and size are important considerations for HVAC systems, they do not pose the immediate threat to safety that a compromised heat exchanger does. Therefore, the safety aspect assumes greater significance in the context of rooftop package units.