Understanding the HVAC/R Sequence of Operation (SOO)

Every piece of equipment has a story. In HVAC/R, that story is the Sequence of Operation (SOO). For an RTU, it starts with a call for heat, then the inducer motor starts, the pressure switch proves airflow, and finally, the igniter glows. If a technician doesn’t know the SOO, they are just guessing. At A/C Dr. Naz, we map the SOO for every diagnostic to find exactly where the logic chain is breaking.

H3: Why is the Sequence of Operation important for diagnostics? It allows a technician to work backward from the failure point to find the actual culprit, rather than just replacing the part that isn’t turning on.

Technical Problem Solvers

We solve the “unsolvable” problems by using engineering-first logic.