520413-BIM-A-0209
Johnson Controls Unitary Products
27
To check the supply air CFM after the initial balancing has
been completed:
1.
Drill two (2) 5/16-inch holes in the side panel as shown in
Figure 24.
2.
Insert at least 8 inches of 1/4 inch tubing into each of these
holes for sufficient penetration into the airflow on both
sides of the evaporator 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 pressure
drop across the wet coil under field conditions would be
inaccurate. To assure a dry coil, the refrigerant system
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 can be determined from the curves
shown in Figure 12.
If the CFM is above or below the specified value, the supply air
motor pulley may have to be readjusted. After one hour of
operation, check the belt and pulleys for tightness and
alignment.
After readings have been obtained, remove the tubes and seal
up the drilled holes in the side panel. 5/16 inch dot plugs (P/N
029-12880) are available through normal York parts ordering
procedures.
Figure 11: Hole Location For Pressure Drop Reading
Table 18: Blower Motor And Drive Data
Unit
Model
Blower Motor Data
Drive Data
HP
RPM
SF
Frame
Size
Model
Number
Blower
RPM
Range
Adjustable Motor Sheave
Model
Number
Fixed Blower Sheave
Belts
Pitch
Diameter
(in.)
Bore
(in.)
Pitch
Diameter
(in.)
Bore (in.)
Qty.
Pitch
Length
(in.)
Desig-
nation
NH-07
Std
1.5
1725
1.15
56
1VL40
690 - 955
2.4 - 3.4
0.875
AK69
6.5
1.000
1
42.3
A41
HS
2
56HZ
1VL40
863 - 1194
2.4 - 3.4
0.875
AK56
5.2
1.000
1
40.3
A39
NH/NJ-10
Std.
2
1725
1.15
56HZ
1VL40
641 - 887
2.4 - 3.4
0.875
AK74
7.0
1.000
1
45.3
A44
HS
3
56HZ
1VP56
906 - 1121
4.0 - 5.0
0.875
AK84
8.0
1.000
1
48.3
A47
NH/NJ-15
Std.
3
1725
1.15
56HZ
1VP50
565 - 721
2.8 - 3.8
0.875
AK114
11.0
1.000
1
45.3
A44
HS
5
184T
2VP50
707 - 894
3.7 - 4.7
1.125
2B5V94
9.7
1.000
2
41.8
B40
NH/NJ-20
Std.
5
1725
1.15
184T
2VP50
686 - 866
3.7 - 4.7
1.125
2B5V94
9.7
1.188
2
41.8
B40
HS
7.5
213T
2VP65
925 - 1138
5.2 - 6.2
1.375
2B5V94
9.7
1.188
2
46.8
B45
Failure to properly adjust the total system air quantity
can result in extensive blower damage.
DRILL Ø 5/16”
DRILL Ø 5/16”
7.00
7.00
4.50
4.50
COIL SECTION
EVAPORATOR
COIL
FILTERS