Reznor MAPS II Unit Installation Manual - Manual (Page 22)

Form I-MAPS II, Page 22
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FIGURE 10D - Installation of
Outside Air Hood, Option AS16 or
Option AS19, on Cabinet Size C
(Model Sizes 176, 226, 230, 280,
292, 346, 374, 428, and 446 are
always Cabinet C.
For a cross-reference of cabinet size and
model size, refer to the Appendix, page
58.)
6.4 Blowers, Belts,
and Drives
6. Mechanical
(cont'd)
6.4.1 Belts and Belt Tension
Blower systems with 1/2 to 5HP motors are
equipped with either Power Twist Plus ® linked
blower belts or solid belts. The linked belts are
designed in sections allowing for easy sizing
and adjustment. Blower systems with 7-1/2 or
10 HP motors have solid V-belts. The belt is
sized at the factory for the proper tension. Check belt tension. Proper belt ten-
sion 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.
Linked Belts - If the belt needs tightening, the recommended method of tight-
ening the belt length is to count the number of links and remove one link for
every 24. (A link is made up of two joining sections of belt. For easier removal
of links, turn the belt inside out. But be sure to turn it back before installing. If
belt is removed or replaced, be sure to align directional arrows on the belt to
the proper drive rotation.) The belt tension should be checked after the first 24
hours of running at full load and at regular maintenance inspections.
Solid Belts - Adjust the belt tension by turning the adjusting screw on the motor
base until the belt can be depressed 3/4" (19mm). (See FIGURE 11.) After cor-
rect tension is achieved, re-tighten the locknut on the adjustment screw. Be
sure that the belt is aligned in the pulleys.
6.4.2 Adjusting
Blower Speed
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WARNING: All set-
screws and lock-
ing collars must be
tightened before
applying power.
Pulley/Shaft Setscrews -
Wrench torque 110 in-lb
minimum to 130 in-lb maxi-
mum.
Bearing Hub - Socket size
5/16"; Torque 165 in-lbs.
NOTE: The information
in Paragraph 6.4 also
applies to an optional
power exhaust blower.
FIGURE 11 - Belt
Tension
6.3 Inlet Air Hood
(cont'd)
FIGURE 9D - Cabinet Size C with or without a power exhaust option -
Attach the top filter filler, the two vertical filter supports and the two side fil-
ter angles. Attach the two inner filter spacers with wing screw receptacles.
Position the nine filters in the opening as shown. Secure the filters with the
filter clamps and the wing screws.
The blower speed may be adjusted to achieve the desired outlet temperature.
If the system includes a gas heat section, any adjustment must be within the
temperature rise and the static pressure limits shown on the furnace rating
plate. Temperature rise is the difference between the inlet air temperature and
the discharge air temperature at high fire. Allowable temperature rise range for
a gas heat section is 45 to 100°F. Motors are factory set between maximum
and minimum blower speeds.
If the duct resistance is low, the blower may deliver too high an air volume. If
the resistance is very low, the blower may deliver enough excess air to over-