Reznor MAPS II Unit Installation Manual - Manual (Page 23)

Form I-MAPS II, P/N 206131 (Rev 13), Page 23
To make adjustments
to units with less than a
5HP motor, follow these
instructions:
For units with 5 HP and
larger motor, follow
these instructions for
adjusting RPM:
amp the motor, causing the overload protector to cycle the motor. Reducing the
blower speed will correct these conditions. If ductwork is added to an instal-
lation, it may be necessary to increase the blower speed. Decreasing blower
speed will increase outlet temperature (heating) or decrease outlet tempera-
ture (cooling); increasing blower speed will decrease outlet temperature (heat-
ing) or increase outlet temperature (cooling).
At final adjustment, amperes should not exceed motor nameplate amp rating.
If gas heat section is included, the temperature rise must be within the 45°F to
100°F range specified on the furnace rating plate. If temperature rise is not in
the approved range, blower speed must be adjusted and gas supply pressure
checked (See Paragraph 9.2.2.1).
Motors are equipped with adjustable pitch pulleys which permit adjustment of
blower speed.
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 pul-
ley 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 turning the
adjusting screw on the motor base until the belt can be depressed 3/4".
(See FIGURE 11.) Re-tighten the lock nut on the adjusting screw. 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.
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 lock-
ing ring (loosened in Step 2).
6. Replace belts and move motor away from the driven shaft to apply suf-
ficient belt tension to prevent slippage. (See FIGURE 11.) 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