What are common indicators of a failing fan bearing in a data center HVAC unit?

• A. Increased vibration, noise, temperature rise, bearing play, and unusual belt wear
• B. Lower vibration and cooler bearings
• C. No unusual noises and stable temperatures
• D. Normal belt wear patterns

Answer: (D)

Failing fan bearings reveal themselves through mechanical changes in how the unit runs. When a bearing wears or degrades, the shaft doesn’t rotate smoothly, which shows up as higher vibration and louder, more noticeable noise. The extra friction from wear also raises the bearing’s temperature, so you may see a local heat rise near the fan. Worn bearings can allow some play in the shaft (bearing looseness), which alters belt tension and tracking and often leads to unusual belt wear patterns. In a healthy unit, you wouldn’t expect these symptoms: there would be no excess vibration or noise, temperatures would stay stable, and belt wear would look normal.