Modine Manufacturing BAE - Manual (Page 8)

8
TOWARD MOTOR
SET SCREW
ADJUSTABLE HALF
OF SHEAVE
3/4" DEFLECTION
WITH 5# FORCE
INSTALLATION
Figure 6
Motor Sheave Adjustment Figure 6a
Belt Tension Adjustment
Blower Adjustments
Following electrical connections, check blower rotation to assure
blow-through heating. If necessary interchange wiring to reverse
blower rotation. Start fan motor and check blower sheave RPM
with a hand-held or strobe-type tachometer. RPM should check
out with the speeds listed in Performance Data shown on pages
18 and 19. A single-speed motor with an adjustable motor
sheave is supplied with these units. If blower fan speed changes
are required, adjust motor sheave as follows:
NOTE: Do not fire unit until blower adjustment has been made
or unit may cycle on limit (overheat) control.
1. Shut-off power before making blower speed adjustments.
Refer to Determining Blower Speed on page 7 and to Blower
Drive Selection on pages 18 and 19 to determine proper
blower RPM.
2. Loosen belt and take belt off of motor sheave.
3. Loosen set screw on outer side of adjustable motor sheave
(see Figure 6).
4. To reduce the speed of the blower, turn outer side of motor
sheave counterclockwise.
5. To increase the speed of the blower, turn outer side of motor
sheave clockwise.
6. Retighten motor sheave set screw, replace belt and retighten
motor base. Adjust motor adjusting screw such that there is
3/4” belt deflection when pressed with 5 pounds of force
midway between the blower and motor sheaves (see Figure
6a). Since the belt tension will decrease dramatically after an
initial run-in period, it is necessary to periodically re-check
the tension to assure continual proper belt adjustment.
7. Check to make certain motor sheave and blower sheave are
aligned. Re-align if necessary.
8. Re-check blower speed after adjustment.
9. Check motor amps. Do not exceed amps shown on motor
nameplate. Slow blower if necessary.
10. Check air temperature rise across unit. Check temperature
rise against values shown in Performance Tables on
pages18 and19 to assure actual desired air flow is being
achieved.
11. If adjustments are required, recheck motor amps after final
blower speed adjustment.
Heater Parts from ACF Greenhouses