Supply Fan (Blower) Section - Bryant 581J-17-28 Service And Maintenance Instructions

Removing the Return Air Filters
1. Remove the return air filter and indoor coil access
panel. See Fig. 1.
2. Reach inside and remove filters from the filter rack.
3. Replace these filters as required with similar replace-
ment filters of same size.
4. Re−install the return air filter and indoor coil access
panel.
Outdoor Air Hood
Outside air hood inlet
aluminum−mesh type filters. See Fig. 2. Inspect these
screens for cleanliness. Remove the screens when
cleaning is required. Clean by washing with hot
low−pressure water and soft detergent and replace all
screens before restarting the unit. Observe the flow
direction arrows on the side of each filter frame.
Economizer Inlet Air Screen
This air screen is retained by spring clips under the top
edge of the hood. (See Fig. 3.)
17 1/4
(438 mm)
DIVIDER
CLEANABLE
ALUMINUM
SCREEN
BAROMETRIC
RELIEF
Fig. 3 − Inlet Air Screen Installation
Remove screens be removing the screws in the horizontal
clips on the leading edge of the hood. Slide the filters out.
See Fig. 3.
Install the filters by sliding clean or new filters into the
hood side retainers. Once positioned, re−install the
horizontal clips.

SUPPLY FAN (BLOWER) SECTION

WARNING
!
ELECTRICAL SHOCK HAZARD
Failure to follow this warning could 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 still applied to
the unit.
screens are permanent
OUTSIDE
AIR
HOOD
FILTER
CLIP
C06027
Supply Fan Assembly
The supply fan system consists of two forward−curved
centrifugal blower wheels mounted on a solid blower shaft
that is supported by two greasable pillow block concentric
bearings. A fixed−pitch driven fan pulley is attached to
the fan shaft and an adjustable−pitch driver pulley is
mounted on the motor. The pulleys are connected using a
V−belt. (See Fig. 4.)
BLOWER
SHAFT
V-BELT
Fig. 4 − Belt Drive Motor Mounting
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
5/8−in. (1.6 cm) deflection when measured at the center
line 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
edge across the belt surface at the pulleys, then push down
on the belt at mid−span using one finger until a 1/2−in.
(1.3 cm) deflection is reached.
1/2"
(1.3 cm)
BELT
DEFLECTION
Fig. 5 − Checking Blower Moter Belt Tension
Adjusting the Belt Tension
Use the following steps to adjust the V−belt tension. See
Fig. 4.
4
BLOWER 15" X 17"
BLOWER
18" X 15"
MOTOR
MOTOR ADJUSTMENT
BOLTS (4)
JACKBOLT LOCKING NUT (2)
MOTOR MOUNTING PLATE
JACKBOLT (2)
STRAIGHTEDGE
BROWNING BELT
TENSION CHECKER
C12260
C12093