Trane QFNA-IOM-1 - Manual (Page 29)

Table 14, as shown below, can be
used to diagnose apparent
problems or failures in the fan.
This table is intended as a
diagnostic aid only. For detailed
diagnostics and repair, contact your
local Trane Service Company.
QFNA-IOM-1 29
Troubleshooting
Table 14 —Fan Troubleshooting
Symptom Cause Remedy
Excessive vibration or noise
(See Table in General
Maintenance section)
Components worn, misaligned, or
loose
Replace, re-align, or tighten parts. Align
bearing screws, if needed. Loosen and
Retighten bearing set screws.
Wheel unbalanced Balance Wheel
Over tensioned belts Adjust belt tension
Misaligned drive Align drive
Isolation system not functioning
properly
Inspect and adjust isolators
Foreign material in fan housing Clear housing
Bearing defective, contaminated, or
not lubricated properly
Replace or lubricate bearing as needed
Bent shaft Correct shaft alignment
Bearing is excessively hot
Note: Bearings on high-speed
fans can run 75
°
above
ambient
First start after lubrication; grease
has not fully redistributed
Clean surface of grease and purge
Parts over lubricated Clean surface of grease and purge
Belts over tensioned Adjust belt tension
Parts not lubricated properly
Apply lubricant. Check bearings for
damage
Misaligned bearing Correct alignment. Check shaft level
Loose fan belt
Motor is poorly positioned Adjust tension
Worn or damaged belt Replace belt. Check sheave alignment
Worn sheaves Replace sheaves
Short belt life
Worn sheaves
Realign drive with MVP sheave set at
mean pitch diameter
Misaligned belt
Realign drive with MVP sheave set at
mean pitch diameter
Grease or oil on belts
Check for leaky bearings. Clean belts and
sheaves
Belts slipping Adjust tension
Belts rubbing
Remove obstruction or re-align drive for
clearance
HP too high
Fan speed above design
Check for leaky bearings. Clean belts and
sheaves
Static pressure above design
Low CFM
Leaks or obstruction in duct system Fix leaks and remove obstruction
Access door open Close door
RPM too low Check fan RPM and adjust as needed
System resistance higher than
design
Variable inlet vanes partially closed Open vanes