Reznor RECC Unit Installation Manual - Manual (Page 40)

Form I-MAPSIII&IV, Page 40
1. If equipped with gas heat, turn off the gas. Always disconnect the electric power.
2. Loosen belt tension and remove the belt.
3. Loosen the set screw on the side of the pulley away from the motor.
4. To increase the blower speed, turn the adjustable half of the pulley inward. To
decrease the blower speed, turn the adjustable half of the pulley outward. One
turn of the pulley will change the speed 8-10%.
5. Tighten the set screw on the flat portion of the pulley shaft.
6. Replace the belt and adjust the belt tension. Adjust tension by following the
appropriate instructions in Paragraph 6.6.1. Be sure that the belts are aligned in
the pulley grooves properly and are not angled from pulley to pulley.
7. Turn on the gas and electric. Light the heater following the instructions on the
lighting instruction plate.
8. Check the motor amps with an amp meter. The maximum motor amp rating on the
motor nameplate must not be exceeded.
9. When service is complete, check for proper operation. When service is complete,
check for proper operation.
To make adjustments
to units with less than a
5HP motor, follow these
instructions:
6.6 Blowers, Belts, and Drives (cont'd) 6.0 Mechanical
(cont'd)
For units with 5 HP and
larger motor, follow
these instructions for
adjusting RPM:
1. If equipped with gas heat, turn off the gas. Always disconnect the electric power.
2. Slack off all belt tension by moving motor towards driven shaft until belts are free
of grooves. For easiest adjustment, remove the belts from the grooves.
3. On the outer locking ring, locate the two locking screws that are directly across
from each other. Loosen these two screws, but do not remove them. Do not loosen
any other screws.
4. Adjust sheave to desired pitch diameter by turning the outer locking ring. One
complete turn of the outer locking ring will result in .233" change in pitch diameter.
To decrease blower speed, increase diameter; to increase blower speed, decrease
diameter.
CAUTION: Sheaves should not be adjusted in either direction to
the point where movable and stationary flanges are in contact.
5. After completing adjustment, tighten both locking screws in the outer locking ring
(loosened in Step 2).
6. Replace belts and move motor away from the driven shaft to apply sufficient belt
tension to prevent slippage. (See FIGURE 20.) Proper belt tension is important to
the long life of the belt and motor. A loose belt will cause wear and slippage. Too
much tension will cause excessive motor and blower bearing wear. Be sure that
the belts are aligned in the pulley grooves and are not angled from pulley to pulley.
7. Check motor amps with an amp meter. The maximum motor amp rating on the
nameplate must not be exceeded.
8. When service is complete, check for proper operation.
CFM = (Input rate x .80) divided by (1.08 x temperature rise)
The belt drive on these units is equipped with an adjustable pulley which permits
adjustment of the blower speed.
FIGURE 21 - Split Taper
Bushing
(3) Cap
Screws
(2)
Push-Off
Holes
6.6.3 Blower Pulley
Some blower pulleys require the use of a split taper bushing in the blower pulley. These
split taper bushings must be loosened in order to remove the pulley. Follow these
instructions to loosen the bushing:
a) Notice that there are three cap screws in the bushing and two holes without
screws, called push-off holes. (See FIGURE 21.)
b) Remove the three cap screws.
c) Put two of the cap screws into the two push-off holes. Tighten these two screws
evenly until the pulley is loosened.
d) Pulley may now be removed from the shaft.