Air Balance; Rpm Selection; Indoor Blower Specifications; Power Exhaust Specifications - York ZF 180 Series Installation Manual

1061903-XIM-A-0713
Table 21: RPM Selection
Size
Model HP
(Tons)
180
ZF 4.1
(15)
240
ZF 6.2
(20)
* Maximum blower speed is 1400 RPM for ZF180 and 1200 RPM for ZF240
Table 22: Indoor Blower Specifications
Size
Model
(Tons)
HP
180 (15) ZF 4.1
240 (20) ZF 6.2
Table 23: Power Exhaust Specifications
Voltage
HP
460-1-60 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 7.
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.
32
Motor Blower
Max BHP
Sheave Sheave
4.72 1VP62 BK75
7.13 1VP75 BK100
Motor
RPM Eff. SF
1450 0.89 1.15
1450 0.91 1.15
Motor
1
RPM QTY LRA
1075 1 4.1
6 Turns 5 Turns
Open Open
925 967
895 926
Motor Sheave
Datum Dia.
Frame Bore (in.) Model
(in.)
184T 4.4 - 5.4 1 1/8
213T 5.8 - 6.8 1 3/8
Motor
FLA MCA
2.2 2.75
PRESSURE DROP ACROSS A DRY INDOOR COIL VS
0.7
0.65
0.6
0.55
0.5
0.45
0.4
0.35
0.3
0.25
4 5
Figure 24: 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 24.
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.
4 Turns 3 Turns 2 Turns
Open Open Open
1009 1051 1093
956 987 1018
Blower Sheave
Datum Dia.
Bore (in.)
(in.)
1VP62 6.9 1
1VP75 9.4 1 3/16
CFM @
0.1 ESP
5250
SUPPLY AIR CFM FOR ALL UNIT TONNAGES
180MBH
6 7 8 9
NOMINAL CFM (THOUSANDS) SUPPLY AIR
Johnson Controls Unitary Products
1 Turn Fully
Open Closed
1135 N/A
1049 N/A
Belt
Model
BK75 BX68
BK100 BX81
240MBH
10 11 12 13