Installation manual

McQuay IM 487-4 91
Unit Options
Figure 103. Belt adjustment Figure 104. Drive pulley alignment
Figure 105. Propeller exhaust fan replacement parts list
B e l t S p a n
D e f l e c t i o n =
B e l t S p a n
6 4
C e n t e r l i n e s
m u s t c o i n c i d
e
M u s t b e
p a r a l l e l
M u s t b e
p a r a l l e l
A d j u s t a b l e
S h e a v e
M o t o r
B e a r i n g
Table 15: Propeller exhaust fan troubleshooting
Problem Cause Corrective Action
Reduced
Airflow
System resistance is too
high.
Check backdraft dampers for proper operation. Remove obstructions in ductwork. Clean dirty filters.
Check for adequate supply for air exhaust fans or exhaust air for supply fans.
Unit running backwards. See “Prestarting Checks” on page 90
Fan speed too low. Increase fan speed
Excessive dirt on propeller. Clean propeller
Excessive
Noise
Bearings Tighten bearing collars and setscrews. Lubricate bearings. Replace defective bearings.
V-Belt drive Tighten pulleys on motor shaft and fan shaft. Adjust belt tension. Align pulleys. Replace worn belts or pulleys.
Excessive vibration Clean dirt build-up from propeller. Check all setscrews and fasteners for tightness. Check for worn bearing.
Correct propeller imbalance. Check for loose dampers, guards or ductwork.
Defective motor Replace motor.
9
8
7
10
6
5
4
1
2
3
1. F an pa nel
2. P ropeller
3. D rive fr ame
ch anne l ( 2)
4. M otor pl ate
5. M otor
6. M otor pu lley
7. S haft pu lley
8. F an sh aft
9. B earings
10. B elt
11. B earing pl at
e
11