Nordyne Light Commercial Air Handler B5SM -090 - Manual (Page 9)

9
Figure 3. Proper Belt Tension
1/4 inch
1 f
oot
Pulley Alignment
Inspect the pulley alignment between the motor sheave
and blower pulley. If a misalignment occurs, adjust the
location of the motor sheave by loosening the set-screw
in the stationary face of the motor sheave. Relocate the
sheave assembly on the motor shaft to ensure the belt will
be straight and aligned (Figure 2). Tighten the set-screw
and then reinstall the fan belt. Tighten the tensioning bolts
as described below.
Belt Tensioning
Proper belt tension can be determined by testing the
belt defl ection at the midpoint of the pulleys. The belt
should defl ect ¼” per foot of span between the centers
of the pulleys (Figure 3). After the proper tension has
been applied, tighten the motor mount bolts to secure
the assembly, and visually inspect the area to ensure all
tools have been removed. Inspect all wire harness and
routings in the vicinity and make sure there is adequate
clearance for the wire harness.
Blower Adjustments - 3 phase units only
If blower is turning opposite of arrow direction, disconnect
all power to unit and allow all rotating equipment to stop,
then interchange any two fi eld wired leads at the terminal
block OR disconnect connections.
The blower speed has been preset at the factory. For
optimum system performance and comfort, it may be
necessary to change the factory set speed. Adjustment
of the blower speed is made through varying the pitch of
the motor pulley, this adjustment allows for a wide range
of installation applications. Refer to Table 4 (page 12) for
blower performance data.
WARNING:
Never perform maintenance on energized or rotating
equipment. Always disconnect electrical power and
allow all rotating equipment to stop before servicing
the unit. Failure to do so may result in personal
injury, loss of limb, or death from electrical shock
or entanglement in moving parts.
UNIT MAINTENANCE
The maintenance information listed below should be
performed in accordance with the Maintenance Schedule
shown in Figure 9 (page 16).
Filters
To clean permanent fi lters, remove the fi lters and wash
gently with mild soap and water. Rinse in clean, hot water
and allow to drain & dry thoroughly before reinstalling.
Drain Pan
The drain pan and the drain lines should be cleaned to allow
condensate to drain properly. Remove any accumulation
of residue or sludge from the drain pan. Inspect in and
around the drain pan for rust, holes, and leaks.
V-Belts
Inspect for cracks, tears, and excessive or abnormal wear.
V-belts tend to elongate over time with normal application
and use. Ensure the belt always maintains adequate
tension without over tightening. Belts which have been
over tightened will wear out rapidly and may cause motor
and blower bearings to receive undue strain and wear.
As a result the unit could experience excessive vibration
and noise problems.
Blower Bearings
The blower assembly incorporates sealed bearings. Under
normal operating conditions, no maintenance is necessary
for the life of the equipment.
Blower Fan Wheel
Inspect the blower wheel blades for accumulations of dirt
and clean if necessary. Inspect mounting nut for tightness
when done.
Blower Motor and Assembly
Inspect the blower assembly and motor mounting
brackets for tightness and corrosion. Correct defi ciencies
if neccessary. The blower motor contains sealed bearings
and under normal operating conditions, no maintenance
is necessary for the life of the equipment.
Figure 2. Proper Belt Alignment