Industrial Ventilation - 8. Troubleshooting

What is covered in this document?

This document is part of a series of documents on industrial ventilation, and includes general troubleshooting tips.

context Introduction
context Units and Measures
context Ducts
context Fans
context Hoods
context Air Cleaning Devices
context Installation and Maintenance (general)
context Troubleshooting
context Glossary of Common Terms

What are some troubleshooting tips for hoods, ducts, air-cleaning devices and fans?

requirement Hood located too far away from process or operation generating point.
requirement Cross drafts or turbulence close to hood.
requirement Blocked duct work.
requirement Fan malfunction.
requirement Increased resistance through air-cleaning equipment.
requirement 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.
requirement Inadequate transport velocity (speed).
requirement Flexible ducts used in place of rigid ducts (results in extra friction loss).
requirement Condensation of salts.
requirement Dented ducts.
requirement Elbows with sharp turns.
requirement Holes in ducts.
requirement Disconnected or broken branch connections.
requirement Closed or partially closed dampers (blast gates).
engineering Addition of hoods and branches to the system without making adjustments to rebalance the ventilation system.
requirement Improper filter type and/or installation.
requirement Improper bag cleaning cycles.
requirement Water intrusion into the filter.
ppe Filter hopper not continuously emptied and cleaned.
administrative Improper "clean start-up procedure" for new bags.
requirement Bags installed improperly.
requirement Torn or damaged bags.
requirement Leakage between bags and housing.
requirement General filter fabric failure.
administrative Excessive dust loading due to lack of maintenance and scheduled cleaning.
requirement Dirty filters.
requirement Air bypassing filter section (rip or tears in filter).
requirement Dirty air handling cabinet housing.
requirement Exhaust stacks placed close to supply air intakes.
requirement Drain pans not operating properly.
requirement Drain pans overflowing.
requirement Out-of-balance fan impeller.
requirement Material on fan blades.
requirement Loose fan housing or foundation bolts.
requirement Fan running backwards.
requirement Vibrating ducts.
requirement Foreign material in fan housing.
requirement Fan running backwards.
requirement Fan speed too slow.
requirement Dirty fan blades.
requirement Actual system has more resistance than designed for.
requirement Dampers closed.
requirement Leaks in duct work.
requirement Dirty or clogged filters in air cleaning device.
requirement Obstructed fan inlets causing system effects (No straight duct runs at fan inlet or outlet).
requirement Fan not getting adequate make-up air.
requirement Access door open.
requirement Filters not in place or tears in filters.
requirement System resistance low.
requirement Fan speed too fast.
requirement Blown fuses.
requirement Broken belts.
requirement Loose pulleys.
requirement Electricity turned off .
requirement Fan impeller touching housing.
requirement Wrong voltage.
requirement Motor too small (overload protector had broken circuit).
requirement Low voltage.
requirement Fan load too large for motor.
requirement Seized bearing.
requirement Fact sheet confirmed current: 2023-06-21