PROBLEM
PROBABLE CAUSE
Noise
Impeller hitting inlet ring
a. Impeller not centered in inlet ring.
b. Inlet ring damaged
c. Crooked or damaged impeller
d. Shaft loose in bearing
e. Impeller loose on shaft
f. Bearing loose in bearing support
Impeller hitting cutoff
a. Cutoff not secure in housing
b. Cutoff damaged
c. Cutoff improperly positioned.
Drive
a. Sheave not tight on shaft (motor and/or fan)
b. Belts too loose. Adjust for belt stretching after
48 hours of operation.
c. Belts too tight.
d. Variable pitch sheaves not adjusted so each
groove has same pitch dia. (multi-belt drives).
e. Misaligned sheaves
f. Belts worn
g. Isolation base shipping restraints not removed.
h. Belts oily or dirty
Bearing
a. Defective bearing
b. Needs Lubrication
c. Loose on bearing supports
d. Loose on shaft
e. Seals misaligned
f. Foreign material inside bearing
g. Worn bearing
h. Fretting corrosion between inner race and shaft.
Shaft Seal Squeal
a. Need lubrication
b. Misaligned
Impeller
a. Loose on shaft
b. Defective Impeller
Do not run fan - Contact manufacturer.
c. Unbalanced
Noise (Continued)
d. Worn as result of abrasive or corrosive
SOLUTION
TROUBLE SHOOTING GUIDES
FANS