•High
grain loading
•Incorrectly
designed pick-up hood
•Oil
carry-over from process
•Moisture
/ Oil in compressed air lines
•Failure
to continuously discharge material
•Purposely
storing material in the hopper
•Bridging
/ Material sticking to hopper sides
•Inleakage
•Airlock
leaking
•Baghouse
/ ductwork leaks