Supply Fan (Blower) Section - Carrier 50TCQD17-D24 Service And Maintenance Instructions

Economizer and Manual Outside Air Hood Screen
The Manual Outside Air Hood Screen is secured by three
screws and a retainer angle across the top edge of the
hood. See Fig. 3.
Fig. 3 - - Screens Installed on Outdoor- - Air Hood
(Sizes D08- - 09s Shown)
Remove the screen by loosening the three screws in the
top retainer and move the retainer up until the screen can
be removed.
Re- - install the Manual Outside Air Hood Screen by
placing the screen frame in its track, rotating the retainer
back down. Tighten all screws.

SUPPLY FAN (BLOWER) SECTION

WARNING
!
ELECTRICAL SHOCK HAZARD
Failure to follow this warning can cause personal
injury or death.
Before performing service or maintenance operations
on the fan system, shut off all unit power and
Lockout/Tagout the unit disconnect switch. Do not
reach into the fan section with power applied to unit.
Supply Fan (Belt- - Drive)
Fig. 4 - - Belt Drive Motor Mounting
The belt- - drive supply fan system consists of a
forward- - curved centrifugal blower wheel on a solid shaft
with two concentric- - type bearings, one on each side of
the blower housing. A fixed- - pitch driver pulley is
attached to the fan shaft and an adjustable- - pitch driver
pulley is on the motor. The pulleys are connected using a
V- - belt. See Fig. 4.
Belt
Check the belt condition and tension quarterly. Inspect the
belt for signs of cracking, fraying or glazing along the
inside surfaces. Check belt tension by using a spring- - force
tool (such as Browning's "Belt Tension Checker" (p/n
1302546 or equivalent tool); tension should be 6- - lbs at a
5
/ - - in (1.6 cm) deflection when measured at the centerline
8
of the belt span. This point is at the center of the belt
when measuring the distance between the motor shaft and
the blower shaft.
NOTE: Without the spring- - tension tool, place a straight
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edge across the belt surface at the pulleys, then push down
on the belt at mid- - span using one finger until a
(1.3 cm) deflection is reached.
DEFLECTION
Fig. 5 - - Checking Blower Motor Belt Tension
Adjust belt tension by loosening the motor mounting plate
front and rear bolts and sliding the plate toward the fan (to
reduce tension) or away from fan (to increase tension).
Ensure the blower shaft and the motor shaft are parallel to
each other (pulleys aligned). When finished, tighten all
bolts and torque to 65- - 70 in- - lb (7.4 to 7.9 Nm).
Replacing the V- -Belt:
NOTE: Use a belt with the same section type or similar
size. Do not substitute a FHP- - type (cogged) belt. When
installing the new belt, do not use a screwdriver or
pry- - bar to force the belt over the pulley flanges, this will
stress the belt and cause a reduction in belt life. Damage
to the pulley can also occur.
EQUIPMENT DAMAGE HAZARD
Failure to follow this CAUTION can result in
premature wear and damage to equipment.
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Do not use a screwdriver or a pry bar to place the new
V- - belt in the pulley groove. This can cause stress on
the V- - belt and the pulley resulting in premature wear
on the V- - belt and damage to the pulley.
4
STRAIGHTEDGE
BROWNING BELT
TENSION CHECKER
1/2"
(1.3 cm)
BELT
CAUTION
1
/ - - in.
2
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