Centrifugal blowers contain a myriad of moving parts -- and, as with any equipment that includes moving parts, it needs to be properly maintained (for further assistance, contact local professionals, such as those from http://www.compressor-pump.com). Luckily a centrifugal blower's components are primarily fan mechanisms, which are constructed of fairly simple components. When issues do occur, they are usually due to a few common issues. 

1. Leaking Seals

Frequently leaking seals are generally due to environmental issues, such as either excess heat or excess cold. Many seals will be rated for specific temperature extremes. Contacting seals can be used within the blower to reduce leakage, but the seals will need to be replaced more often. Non-contacting seals will leak, but they will not need to be replaced as frequently. Either seal will need to be properly lubricated.

2. Ball Bearing Failure 

Ball bearings may fail more frequently than they should if the proper lubrication isn't used within the blower. Oil lubrication is preferred over grease lubrication for blower parts and the oil should only be used for the time period suggested by the producer. Additionally, the blower should be re-lubricated and cleaned as often as indicated. If vibration or ball bearing failure persists, it may be loose parts or damage within the machinery itself.

3. Excess Vibration

Vibration can happen for several major reasons: shaft misalignment, resonance, mass unbalance, cracked shafts, damaged rotors or loose connections. Diagnosing a vibration problem usually involves troubleshooting each issue at a time. Cracked shafts or rotors will usually be visibly identifiable once the casing is open. Loose connections, on the other hand, can be diagnosed by observing the blower in action and looking for inactive parts. 

4. Unusual Sounds

Unusual sounds (when accompanied by poor operation) usually indicate that not enough air is being directed through the blower. These unusual noises can be used to diagnose more serious issues that are occurring within the machine. A centrifugal blower will often not get the necessary airflow if it has dirty filters or plugged diffusers. Cleaning out the machine is usually the first step in troubleshooting this issue. If the machine is not blocked, there may be a part that needs replacement: butterfly valves, closed valves or bearings. 

For many blowers, a call to the manufacturer can assist in troubleshooting recurring issues. A Hoffman blower or Lamson blower will usually have technicians available through Hoffman and Lamson for more serious equipment issues, such as a bent shaft or mechanical misalightment.