Installation manual

035-16682-000-E-0303
62 Unitary Products Group
1. Remove the dot plugs from the two 5/16 inch holes in the
blower motor and the filter access doors.
2. Insert at least 8 inch of 1/4 inch metal tubing into each of
these holes for sufficient penetration into the air flow on
both sides of the indoor coil.
3. Using an inclined manometer, determine the pressure
drop across a dry evaporator coil. Since the moisture on
an evaporator coil may vary greatly, measuring the pres-
sure drop across a wet coil under field conditions would
be inaccurate. To assure a dry coil, the compressors
should be de-activated while the test is being run.
4. Knowing the pressure drop across a dry coil, the actual
CFM through the unit with clean 2 inch filters, can be
determined from the curve in Figure 58 and 59.
After readings have been obtained, remove the tubes and
reinstall the two 5/16 inch dot plugs.
NOTE: De-energize the compressors before taking any test
measurements to assure a dry evaporator coil.
TABLE 31: BELT ADJUSTMENT
FAN MOTOR HORSE POWER 5 7.5 10 15 20 25
30 TON FORWARD CURVED SUPPLY FAN SIZE: 22 X 20
Belt Deflection Force (lbs) new belts - - 10.5 12.6 15.2 22.1
Belt Deflection Force (lbs) old belts - - 7.1 8.5 10.2 14.8
40 TON FORWARD CURVED SUPPLY FAN SIZE: 25 X 20
Belt Deflection Force (lbs) new belts - - 10.5 12.6 15.2 15.2
Belt Deflection Force (lbs) old belts - - 7.1 8.5 10.2 10.2
30 & 40 TON POWER EXHAUST FAN SIZE: (2) 15 X 15
Belt Deflection Force (lbs) new belts - 7.9 9.4 9.4 - -
Belt Deflection Force (lbs) old belts - 5.3 6.3 6.3 - -
25 TON FORWARD CURVE SUPPLY FAN SIZE: 22 X 20
New Belt - 10.5 10.5 12.6 15.2 -
Old Belt - 7.1 7.1 8.5 10.2 -
25 TON POWER EXHAUST
New Belt 10.5 10.5 12.6 - - -
Old Belt 7.1 7.1 8.5 - - -
Failure to properly adjust the total system air quan-
tity can result in extensive blower damage.