Lennox International Inc. G24-200 - Manual (Page 14)

Page 14
TYPICAL MOTOR/DRIVE INSTALLATION
MOTOR PULLEY
MOTOR
MOTOR SECURING
HARDWARE
BELT TENSION ADJUSTING HARDWARE
PULLEY ALIGNMENT
BLOWER
PULLEY
MOTOR
PULLEY
MOTOR BASE
FIGURE 7
B − Blower Belt Adjustment
Maximum life and wear can be obtained from belts only if
the proper pulley alignment and belt tension are main-
tained. Tension new belts after a 24 to 48 hour period of op-
eration. This will allow the belt to stretch and seat in the
grooves.
1 − Loosen belt adjusting hardware. See figure 7.
2 − To increase belt tension −
Move the motor base away from the blower housing.
To loosen belt tension −
Move the motor toward the blower housing.
3 − Tighten the belt adjusting hardware.
C − Check Belt Tension
Over-tensioning a belt shortens belt and bearing life.
Check belt tension as follows:
1 − Measure span length X. See figure 8.
2 − Apply perpendicular force to the center of span (X)
with enough pressure to deflect belt 1/64 inch for ev-
ery inch of span length or 1.5mm per 100mm of span
length.
Example: Deflection distance of a 40 inch span would
be 40/64 inch or 5/8 inch.
Example: Deflection distance of a 400mm span would
be 6mm.
3 − Measure the belt deflection force. For a used belt, the
deflection force should be 5 lbs. (35kPa). A new belt
deflection force should be 7 lbs. (48kPa).
A force below these values indicates an under-ten-
sioned belt. A force above these values indicates an
over-tensioned belt.
MEASURE BELT TENSION
DEFLECTION 1/64 INCH PER INCH OF SPAN
OR 1.5 mm PER 100 mm OF SPAN
FORCE
FIGURE 8
Venting
A vent adapter is factory-installed on each of the combus-
tion air blower outlets. Modification of, or removal of the
adapter(s) will cause unsafe unit operation and will
void CSA unit certification. The vent adapter does not re-
quire insulation.
The G24−200 units are classified as fan assisted Category I
type furnaces when vertically vented according to the latest
edition of ANSI Z21.47 Gas-fired Central Furnace Standard
in the USA and the current standard CSA 2.3 Gas-fired Cen-
tral Furnace in Canada. The definition of a fan assisted fur-
nace is an appliance equipped with an integral mechanical
means to either draw or force products of combustion
through the combustion chamber and/or heat exchanger.
NOTE − Use these instructions as a guide. They do not su-
persede local codes.
The vent sizing tables in this manual have been extracted
from the Current edition of the National Fuel Gas Code
(NFPA 54 / ANSI Z223.1) and are provided as a guide for
proper vent installation. Proper application, termination,
construction and location of vents must conform to local
codes having jurisdiction. In the absence of local codes,
the NFGC serves as the defining document in the U.S.A.,
while the CSA−B149 codes serve as the defining docu-
ments in Canada.
Refer to the tables and the venting information contained in
these instructions to properly size and install the venting
system.
Install the first vent connector elbow a minimum of 6 in.
(152mm) from the furnace vent outlet.