Conair Hopper Temperature Controller UGD031 - Manual (Page 94)

A D - 1 2 l A d d e n d u m
B l o w e r Tr o u b l e s h o o t i n g
( c o n t i n u e d )
Problem
Excessive vibration and/or
noise (continued).
Possible cause
Worn bearings.
Damaged wheel or motor.
Broken or loose bolts and setscrews.
Bent shaft.
Fan wheel or driver unbalanced.
120 cycle magnetic hum due to electrical
input.
Fan delivering more than rated capacity.
Loose dampers or variable inlet vanes.
Fan rotation in wrong direction.
Vibration transmitted to the fan from
some other source.
Solution
Replace the worn bearings.
Replace the damaged wheel and/or
motor.
Tighten or replace all loose bolts and/or
setscrews as needed.
Replace the motor.
Balance the wheel or driver following
factory instructions.
Check for high or unbalanced voltage.
Reduce the flow by throttling the dis-
charge damper.
Tighten any loose dampers or inlet
vanes.
Reverse the electrical connections at the
motor starter.
Make sure the fan is properly isolated
from the rest of the system.