When taking a measurement for temperature rise, where should the supply air temperature be taken?

Taking the supply air temperature measurement at a point above and out of the direct line from the heat exchanger is essential for obtaining an accurate representation of the temperature of the air being delivered into the conditioned space. This location ensures that the air has had sufficient time to absorb heat from the heat exchanger, reflecting the true heated output of the system. It minimizes the influence of any local thermal effects directly around the heat exchanger and allows for an accurate assessment of the temperature rise across the system.

Measuring in this way also helps to account for the uniformity of air distribution throughout the ductwork, ensuring that the temperature reading is representative of what occupants will experience once the air is circulated into rooms. Understanding this principle is vital for diagnosing and optimizing system performance, as it allows technicians to make informed decisions based on reliable temperature readings.