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Table 11: Noise troubleshooting
Problem
Symptoms
Possible Causes
Solutions
Noise
Shaft pillow
block bearing
noise
Lack of grease
Add grease
Worn or damaged
bearings
Replace pillow blocks
Motor noise
Lack of grease
Add grease
Worn or damaged
bearings
Replace bearings or
motor
Worn or damaged
bearings from VFD
controls
Replace bearings or
motor & use ceramic
coated bearings
and/or shaft
grounding devices to
extend life of motors
Not wired correctly
Check for loose or
incorrect wiring
Wrong voltage
applied to motor
Check available
operating voltage vs
motor nameplate
Operated by VFD
Adjust VFD settings
and/or add noise
filter and/or proper
wire type
Operated by VFD at
too much speed
turndown ratio
Reduce speed
turndown
Fan noise
Fan hitting fan
guard or fan
openings
Adjust fan position
Radiator noise Loose or missing
fasteners
Tighten loose
fasteners and replace
missing fasteners
Belt noise
Loose belts
Correct belt tension
Sheave alignment
Correct sheave
alignment
Pump
cavitation
noise
Air in coolant flow
Check for correct
venting & makeup
piping
Lack of head
pressure on pump
suction
Check for correct
venting & makeup
piping