Installation manual

IM 178 / Page 57
Supply Fan Wheel-to-Funnel Alignment
If the unit is equipped with an airfoil or backward curved supply
fan, the fan wheel-to-funnel alignment must be as shown in
Figure 37 or 38 to obtain proper air delivery and operating
clearance. If necessary, adjustments are made as follows:
1. Verify that the fan shaft has not moved in its bearings.
2. Loosen the fan hub setscrews and move the wheel(s)
along the shaft as necessary to obtain the correct dimension
shown in Figure 37 or 38.
3. Retighten the setscrews to the torque specification given
in Table 16. Tighten the setscrews over the keyway first;
tighten those at 90 degrees to the keyway last.
4. Verify that the radial clearance around the fan is uniform.
Radial clearance can be adjusted by slightly loosening the
funnel hold-down fasteners, shifting the funnel as required,
and retightening the fasteners.
Figure 37. 20" airfoil wheel-to-funnel (800C)
Figure 38. 24" backward curved wheel-to-funnel (802C)
.25"
.25"
Funnel
Wheel
.18"
9.31"
9.31"
Wheel
Funnel
C
L
Fan
Winterizing Water Coils
Coil freeze-up can be caused by such things as air stratifica-
tion and failure of outdoor dampers and/or preheat coils.
Routine draining of water cooling coils for winter shutdown
cannot be depended upon as insurance against freeze-up.
Severe coil damage may result. It is recommended that all
coils be drained as thoroughly as possible and then treated
in the following manner.
Fill each coil independently with an antifreeze solution
using a small circulating pump and again thoroughly drain.
Check freezing point of antifreeze before proceeding to next
coil. Due to a small amount of water always remaining in each
coil, there will be a diluting effect. The small amount of
antifreeze solution remaining in the coil must always be
concentrated enough to prevent freeze-up.
Note: Carefully read instructions for mixing antifreeze
solution used. Some products will have a higher freezing
point in their natural state than when mixed with water.
Funnel
.25"
Wheel
.25"
Wheel
.18"
Funnel
Fan
9.31"
9.31"