That's an important first step we plan to do. Assuming it shows that operation is in the unstable region, what kinds of things can/should we do to see if fan performance will become erratic? Or is just operating from shut-off to rated flow and back down to shut-off all that needs to be done?
I need to develop a test procedure to prove that an AHU fan (FC centrifugal, dual-inlet, direct-drive) selected in the unstable region of the OEM fan curve won't operate erratically (stalling/hunting/surging). Since the fan is housed in a very tight cabinet with poor airflow conditions...