5
To replace the belt:
1. Use a belt with same section type or similar size. Do
not substitute a “FHP” type belt. When installing the
new belt, do not use a tool (screwdriver or pry--bar) to
force the belt over the pulley flanges, this will stress
the belt and cause a reduction in belt life.
2. Loosen the motor mounting plate front bolts and rear
bolts.
3. Push the motor and its mounting plate towards the
blower housing as close as possible to reduce the cen-
ter distance between fan shaft and motor shaft.
4. Remove the belt by gently lifting the old belt over
one of the pulleys.
5. Install the new belt by gently sliding the belt over
both pulleys and then sliding the motor and plate
away from the fan housing until proper tension is
achieved.
6. Check the alignment of the pulleys, adjust if neces-
sary.
7. Tighten all bolts.
8. Check the tension after a few hours of runtime and
re--adjust as required.
Adjustable--Pitch Pulley on Motor
The motor pulley is an adjustable--pitch type that allows a
servicer to implement changes in the fan wheel speed to
match as--installed ductwork systems. The pulley consists
of a fixed flange side that faces the motor (secured to the
motor shaft) and a movable flange side that can be rotated
around the fixed flange side that increases or reduces the
pitch diameter of this driver pulley. (See Fig. 6.)
As the pitch diameter is changed by adjusting the position
of the movable flange, the centerline on this pulley shifts
laterally (along the motor shaft). This creates a
requirement for a realignment of the pulleys after any
adjustment of the movable flange. Also reset the belt
tension after each realignment.
Check the condition of the motor pulley for signs of wear.
Glazing of the belt contact surfaces and erosion on these
surfaces are signs of improper belt tension and/or belt
slippage. Pulley replacement may be necessary.
To change fan speed:
1. Shut off unit power supply.
2. Loosen belt by loosening fan motor mounting nuts.
(See Fig. 5.)
3. Loosen movable pulley flange setscrew. (See Fig. 6.)
4. Screw movable flange toward fixed flange to increase
speed and away from fixed flange to decrease speed.
Increasing fan speed increases load on motor. Do not
exceed maximum speed specified.
5. Set movable flange at nearest keyway of pulley hub
and tighten setscrew to torque specifications.
To align fan and motor pulleys:
1. Loosen fan pulley setscrews.
2. Slide fan pulley along fan shaft. Make angular align-
ment by loosening motor from mounting.
3. Tighten fan pulley setscrews and motor mounting
bolts to torque specifications.
4. Recheck belt tension.
C07075
Fig. 6 -- Supply--Fan Pulley Adjustment
Bearings
This fan system uses bearings featuring concentric split
locking collars. The collars are tightened through a cap
screw bridging the split portion of the collar. The cap
screw has a Torx T25 socket head. To tighten the locking
collar: Hold the locking collar tightly against the inner
race of the bearing and torque the cap screw to 65--70
in-lb (7.4--7.9 Nm). (See Fig. 7.)
C08121
Fig. 7 -- Tightening Locking Collar
Motor
When replacing the motor, also replace the external--tooth
lock washer (star washer) under the motor mounting base;
this is part of the motor grounding system. Ensure the
teeth on the lock washer are in contact with the motor’s
painted base. Tighten motor mounting bolts to 120 +/-- 12
in--lbs.
48TC
Summary of Contents for WeatherMaker 48TC*D08
Page 10: ...10 COOLING CHARGING CHARTS C08669 Fig 10 Cooling Charging Charts D08 48TC ...
Page 11: ...11 COOLING CHARGING CHARTS C08670 Fig 11 Cooling Charging Charts D12 48TC ...
Page 12: ...12 COOLING CHARGING CHARTS C09151 Fig 12 Cooling Charging Charts D14 Circuit A 48TC ...
Page 13: ...13 COOLING CHARGING CHARTS C09152 Fig 13 Cooling Charging Charts D14 Circuit B 48TC ...
Page 37: ...37 C08665 Fig 43 Typical PremierLinkt System Control Wiring Diagram 48TC ...
Page 45: ...45 C07129 Fig 60 RTU MP Multi Protocol Control Board 48TC ...
Page 46: ...46 C09163 Fig 61 Typical RTU MP System Control Wiring Diagram 48TC ...
Page 67: ...67 C09156 Fig 84 48TC Typical Unit Wiring Diagram Power D08 208 230 3 60 48TC ...
Page 68: ...68 C09157 Fig 85 48TC Typical Unit Wiring Diagram Control D08 208 230 3 60 48TC ...