19
5-572.10
START-UP PROCEDURE
Blower Adjustments
All belt drive supply fan speed adjustments can be made with
the adjustable sheave on the blower motor as follows:
1. Refer to page 38 to determine correct blower speed
according to job requirements, then proceed to the next
step.
2. Turn off power to the unit at the disconnect switch. If
equipped with gas heat option, turn all hand gas valves to
the “OFF” position.
3. Loosen the belt tension and remove the belt.
4. On the motor sheave, loosen the set screw on the side
away from the motor (see Figure 19.1).
MOTOR
SHAFT
SET SCREW
ADJUSTABLE HALF
OF SHEAVE
Figure 19.1 - Motor Sheave Adjustment
3/4" DEFLECTION
WITH 5 LBS. OF FORCE
Figure 19.2 - Belt Tension Adjustment
9. Retighten motor base. Motor base should be shifted for
proper belt tension which is 3/4" deflection with about 5 lbs.
of force. Refer to Figure 19.2.
10. Turn on power to the unit and initiate blower motor
operation. Do not fire gas controls until blower adjustment
has been made or unit may cycle on high limit control.
5. Turn outer side of motor sheave clockwise until motor
sheave is fully closed.
6. From fully closed position, turn outer side of motor sheave
counterclockwise until the proper number of turns open
are achieved. Turns should be done in half-turns (180°
rotations). Each half turn results in a change of blower
speed and air volume of approximately 2.5-5%. Adjusting
the half of the sheave inward increases blower speed,
adusting outward decreases blower speed.
7. Tighten the set screw on the flat portion of the motor shaft.
8. Replace the belt and verify that the belts are aligned in the
sheave grooves properly and are not angled from sheave
to sheave.
Figure 19.3 - Damper Linkage Adjustment
DAMPER
BLADE
BALL JOINT
CONNECTING ROD
BLADE ARM
11. Check the motor amps to ensure the maximum motor amp
rating is not exceeded. Verify airflow volume and repeat
steps above for further adjustment.
12. If equipped with gas heat, turn on the gas and initiate
burner operation.
13. Verify the temperature rise and supply air temperature of
the heating section do not fall outside the range or exceed
the maximums shown in Table 32.1.
14. After 24 hours of operation, retighten the setscrews to the
torque listed in the owners manual on the bearing, sheave,
and blower wheel to avoid damage to the unit.
Lubrication Recommendations
The blower can be provided with either spider or pillow block
bearings. Spider bearings are permanently lubricated and
do not require lubrication. Pillow block bearings are shipped
greased from the factory but will require lubrication. The
bearings should be checked and lubricated before each heating
season but a more frequent lubrication schedule may be
required based on the environment in which the unit is installed,
and the frequency of the equipment operation. Shell Alvania #2
lubricant is recommended.
Damper Linkage Adjustment
If the unit is provided with a return air damper, to prevent
shipping damage, the return air damper linkage is disconnected
and the damper closed. Before operating the unit, the fresh and
return air dampers must be connected. This is accomplished by
the following:
1. The damper actuator should be de-energized and the fresh
air damper in a fully closed position.
2. Open the return air damper in a fully open position.
3. Slide the connecting rod into the ball joint on the blade arm
with the return air damper fully open. See Figure 19.3.
4. Tighten the 5/16" hex head screw on the ball joint.
