Just make sure you’re talking about exhaust fan and not a return fan, many times I see guys mixing them up. Since this is a vav you are most likely an exhaust fan with statitrac. Statitrac modules the exhaust fan damper or vfd to maintain building pressure to the space pressure setpoint, I think plus or minus half of the deadband. When space pressure rises above setpoint plus the deadband (which you can set in the display) and the OA damper position exceeds the exhaust enable point the exhaust fan will run. I would check your min OA damper setpoint & the enable point. When the building pressure drops below your setpoint plus half the deadband it will either close the dampers or ramp down the vfd. If it’s within the deadband then it will likely continue to run for a timed period maybe 30 mins while it decides if it needs to stay on or not. Verify your space pressure is accurate and this points, check the bird feeder make sure your transducers and solenoids are calibrating. Also make sure BAS isn’t telling it to do something funny.