At what temperature does all air pass through the heat exchanger?

The correct response is that all air passes through the heat exchanger at a temperature of 165°F. This temperature is typically the point at which the system is designed to maximize its efficiency in transferring heat. In heating and air conditioning systems, the heat exchanger is a critical component that facilitates the process of heating or cooling the air.

At 165°F, the heat exchanger is effective in ensuring that the air has been adequately heated before it is distributed throughout the space. This temperature ensures optimal performance, as it allows for a sufficient temperature differential, enabling the heat exchanger to transfer heat efficiently and maintain a comfortable environment.

Understanding the function of the heat exchanger at this specific temperature is essential for effective system design and operation, as it helps technicians know when to expect the air to have been fully treated, ensuring safety and efficiency in HVAC systems.