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Table 16: Indoor Blower Specifications
Size
(Tons)
HP
RPM
-15
5
1725
(15)
5
1725
-18
7.5
1725
(17.5)
7.5
1725
7.5
1725
-20
(20)
7.5
1725
-25
15
1725
(25)
15
1725
Table 17: Power Exhaust Specifications
Voltage
HP
208/230-1-60
3/4
460-1-60
3/4
575-1-60
3/4
1. Motors are multi-tapped and factory wired for high speed.
Air Balance
Start the supply air blower motor. Adjust the resistances in both
the supply and the return air duct systems to balance the air
distribution throughout the conditioned space. The job
specifications may require that this balancing be done by
someone other than the equipment installer.
To check the supply air CFM after the initial balancing has been
completed:
1.
Remove the two 5/16" dot plugs from the blower motor and
the filter access panels shown in the Unit Dimensions and
Rear View Clearances Figure 6.
2.
Insert at least 8" of 1/4 inch tubing into each of these holes
for sufficient penetration into the air flow on both sides of
the indoor coil.
NOTE: The tubes must be inserted and held in a position
perpendicular to the air flow so that velocity pressure
will not affect the static pressure readings.
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 pressure
drop across a wet coil under field conditions would be
inaccurate. To assure a dry coil, the compressors should
be deactivated while the test is being run.
40
Motor
Datum Dia.
Eff.
SF
Frame
0.83
1.15
184T
0.83
1.15
184T
0.89
1.15
213T
0.89
1.15
213T
0.89
1.15
213T
0.89
1.15
213T
0.91
1.15
254T
0.91
1.15
254T
Motor
1
RPM
QTY
LRA
1075
1
7.7
1075
1
4.1
1050
1
2.84
Motor Sheave
Bore (in.)
Model
(in.)
4.3 - 5.3
1-1/8
1VP56
4.3 - 5.3
1-1/8
1VP56
5.5 - 6.5
1-3/8
1VP68
5.5 - 6.5
1-3/8
1VP68
5.5 - 6.5
1-3/8
1VP68
5.5 - 6.5
1-3/8
1VP68
6.2 - 7.4
1-5/8
1VP75X
6.2 - 7.4
1-5/8
1VP75X
Motor
FLA
MCA
5.0
6.25
2.2
2.75
1.5
1.875
Pressure Drop Across A Dry Indoor Coil VS Supply Air CFM
0.45
0.4
0.35
0.3
0.25
0.2
0.15
0.1
0.05
0
4000
5000
Figure 20: Pressure Drop Across A Dry Indoor Coil Vs.
Supply Air CFM For All Unit Tonnages
4.
Knowing the pressure drop across a dry coil, the actual
CFM through the unit can be determined from the curve in
Pressure Drop vs. Supply Air CFM Figure 20.
Failure to properly adjust the total system air quantity
can result in extensive blower damage.
After readings have been obtained, remove the tubes and
reinstall the two 5/16" dot plugs that were removed in Step 1.
NOTE: De-energize the compressors before taking any test
measurements to assure a dry indoor coil.
Blower Sheave
Datum Dia.
Bore (in.)
Model
(in.)
8.4
1
BK90
7.4
1
BK80
11.4
1-3/16
BK120
10.4
1-3/16
BK120
11.4
1-3/16
BK120
10.4
1-3/16
BK120
11.1
1-7/16
1B5V110 5VX860
9.5
1-7/16
1B5V94
CFM @
0.1 ESP
5250
5250
5250
6000
7000
8000
9000
Nominal Air Flow (CFM)
Unitary Products Group
178113-BIM-D-0906
Belt
BX81
BX78
BX83
BX81
BX83
BX81
5VX860
10000
11000
12000
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