21 vii. troubleshooting, Troubleshooting guide – air blower – Sterling RT User Manual
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21
VII. TROUBLESHOOTING
For troubleshooting of the duct furnace, refer to Outdoor Rooftop Gas-Fired Duct Furnace Installation and
Service Manual. For Evaporative Cooler/Cooling Coil equipped units, refer to these specifi c manuals for additional
troubleshooting guides.
For additional troubleshooting, see following Troubleshooting Guide.
TROUBLESHOOTING GUIDE – AIR BLOWER
PROBLEM
PROBABLE CAUSE
SOLUTION
1. Noise
Blower Wheel Hitting Scroll Side
a. Blower Wheel not centered in blower housing.
b. Damaged blower housing.
c. Damaged blower wheel.
d. Shaft loose in blower bearing.
e. Blower Wheel loose on shaft.
f. Blower bearing loose in bearing support.
Blower Wheel Hitting Cutoff
a. Cutoff not secure in blower housing.
b.
Cutoff
damaged.
c. Cutoff improperly positioned.
Drive
a. Pulley not tight on shaft (motor and/or blower
wheel).
b. Belts too loose. Adjust for belt stretching after 48
hours of operation.
c. Belts too tight.
d. Belts wrong cross section.
e. Belts not matched in length on multi-belt drive.
f. Variable pitch pulleys not adjusted so each pulley
has same pitch diameter (multi-belt drives).
g.
Misaligned
pulleys.
h.
Belts
worn.
i. Motor or motor base loose.
j. Belts oily or dirty
k. Improper drive selection
Bearing
a.
Defective
bearing.
b.
Needs
lubrication.
c. Loose on bearing support.
d. Loose on shaft.
e.
Seals
misaligned.
f. Foreign material in bearing.
g.
Worn
bearing.
h. Fretting corrosion between inner race and shaft.
Shaft Seal Squeal
a. Needs lubrication.
b.
Misaligned.