Troubleshooting - Greenheck G Series Installation, Operation And Maintenance Manual

Troubleshooting

WARNING: Before taking any corrective action, make certain unit is not capable of operation during repairs.
PROBLEM
Wheel rubbing inlet
V-belt drive
Bearings
Wheel unbalance
Excessive noise
Belts too tight or too loose
or vibration
Wheel improperly aligned and
rubbing
Loose drive or motor pulleys
Foreign objects in wheel or
housing
Fan base not securely anchored
Motor hood loose and rattling
Defective or loose motor
bearings
Fan
High horsepower
Duct system
Electrical supply
Fan does
Drive
not operate
Motor
Lubrication
Mechanical
Belt slippage
Over/Under line voltage
Motor overloads
or overheats Incorrect wheel rotation
Wheel RPM too high
Undersized motor
Motor wired incorrectly
System resistance too high
Unit running backwards
Excessive dirt buildup on wheels Clean wheel.
Improper wheel alignment
Reduced airflow
Dampers closed
Blocked duct/clogged filter
Belt slippage
Speed too slow
®
CAUSE
Adjust wheel and/or inlet cone. Tighten wheel hub or bearing
collars on shaft.
Tighten pulleys on motor/fan shaft. Adjust belt tension. Align
pulleys properly, see page 6, Figure 9-10. Replace worn belts or
pulleys.
Replace defective bearing(s). Lubricate bearings. Tighten collars
and fasteners.
Clean all dirt off wheel. Check wheel balance, rebalance in place if
necessary.
Adjust tension, see page 7, Figure 12a-b.
Center wheel on inlet, see page 6, Figure 7.
Align and tighten. See "Pre-Starting Checks", see page 6.
Remove objects, check for damage or unbalance.
Secure properly.
Tighten screws securing motor hood.
Replace motor with same frame size, RPM-HP.
Check rotation of wheel, see page 6, Figure 8. Reduce fan speed.
Resize ductwork. Check proper operation of face and bypass
dampers. Check filters and access doors.
Check fuses/circuit breakers. Check for switches off. Check for
correct supply voltage.
Check for broken belts. Tighten loose pulleys.
Assure motor is correct horsepower and not tripping overload
protector.
Check for excessive or insufficient grease in the bearing.
Replace damaged bearing. Relieve excessive belt tension. Align
bearings. Check for bent shaft.
Adjust tension or replace bad belts, see page 6-7.
Contact power company.
Check motor wiring (page 4) verify motor is wired for correct
rotation.
Check drives or slow down fan by opening variable pitch pulley on
motor shaft.
Check motor ratings with catalog speed and air capacity chart.
Check motor wiring to wiring diagram located on fan motor.
Check system: Proper operation of backdraft or control dampers,
obstruction in ductwork, clean dirty filters.
Correct as shown on page 6, Figure 8.
Center wheel on inlets, see Pre-Starting checks on page 6,
Figure 7.
Inspect and repair.
Clean or replace.
Replace and adjust tension.
Check for correct drives.
CORRECTIVE ACTION
Downblast Centrifugal Roof Exhaust Fans 9