What are some troubleshooting tips for hoods, ducts, air-cleaning devices & fans?
Exhaust Hood Problems Possible Cause(s) Low Capture Velocity • Hood located too far away from process or operation generating point. • Cross drafts or turbulence close to hood. • Blocked duct work. Reduced Face Velocity • Unauthorized enlargement of the opening of an existing hood. The face velocity at the hood will decrease resulting in the escape of contaminants held back by the original face velocity. Ducts Problems Possible Cause(s) Constant Plugging • Ducts handling particulates with inadequate transport velocity (speed). • Flexible ducts used in place of rigid ducts (results in extra friction loss). • Condensation of salts. • Dented ducts. • Elbows with sharp turns. • Holes in ducts. • Disconnected or broken branch connections. • Closed or partially closed dampers (blast gates). • Addition of hoods and branches to system without making adjustments to rebalance the ventilation system. Air Cleaning devices Problems Possible Cause(s) Frequent clogging • Improper filter type and/or i
