689670-BIM-A-0311
38
Johnson Controls Unitary Products
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.
Checking Air Quantity
Method One
1.
Remove the dot plugs from the duct panel (for location of
the dot plugs see Figures 12 and 13).
2.
Insert eight-inches of 1/4 inch metal tubing into the airflow
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.
Use an Inclined Manometer or Magnehelic to determine
the pressure drop across a dry evaporator coil. Since the
moisture on an evaporator coil can vary greatly, measuring
the pressure drop across a wet coil under field conditions
could be inaccurate. To assure a dry coil, the compressors
should be de-activated while the test is being run.
NOTE:
De-energize the compressors before taking any test
measurements to assure a dry evaporator coil.
4.
The CFM through the unit can be determined from the
pressure drop indicated by the manometer by referring to
Figure 28. In order to obtain an accurate measurement, be
certain that the air filters are clean.
5.
To adjust Measured CFM to Required CFM, see.
6.
After readings have been obtained, remove the tubes and
replace the dot plugs.
7.
Tighten blower pulley and motor sheave set screws after
any adjustments. Re-check set screws after 10-12 hrs. run
time is recommended.
Table 17: RPM Selection
Size
(Tons)
Model
HP
Max
BHP
Motor
Sheave
Blower
Sheave
6 Turns
Open
5 Turns
Open
4 Turns
Open
3 Turns
Open
2 Turns
Open
1 Turn
Open
Fully
Closed
-A3
(3)
ZU
1.5
1.5
1VM34
AK69
N/A
531
584
637
690
743
796
1.5
1.5
1VL44
AK69
N/A
796
849
902
955
1008
1062
-A4
(4)
ZU
1.5
1.5
1VM34
AK56
N/A
663
730
796
863
929
995
1.5
1.5
1VL44
AK56
N/A
995
1062
1128
1194
1261
1327
-A5
(5)
ZU
1.5
1.5
1VL40
AK61
N/A
787
847
908
968
1029
1089
2
2
1VP56
AK74
N/A
1035
1084
1134
1183
1232
1281
Table 18: Indoor Blower Specifications
Size
(Tons)
Model
Motor
Motor Sheave
Blower Sheave
Belt
HP
RPM
Eff.
SF
Frame
Datum Dia.
(in.)
Bore (in.)
Model
Datum Dia.
(in.)
Bore (in.)
Model
-A3
(3)
ZU
1-1/2
1725
0.8
1.15
56
2.0 - 3.0
7/8
1VM34
6.5
1
AK69
A47
1-1/2
1725
0.8
1.15
56
3.0 - 4.0
7/8
1VL44
6.5
1
AK69
A47
-A4
(4)
ZU
1-1/2
1725
0.8
1.15
56
2.0 - 3.0
7/8
1VM34
5.2
1
AK56
A47
1-1/2
1725
0.8
1.15
56
3.0 - 4.0
7/8
1VL44
5.2
1
AK56
A47
-A5
(5)
ZU
1-1/2
1725
0.8
1.15
56
2.6 - 3.6
7/8
1VL40
5.7
1
AK61
A47
2
1725
0.8
1.15
56
4.2 - 5.2
7/8
1VP56
7.0
1
AK74
A51
Table 19: Power Exhaust Specifications
Model
Voltage
Motor
Motor
Fuse Size
CFM @
0.1 ESP
HP
RPM
1
1. Motors are multi-tapped and factory wired for high speed.
QTY
LRA
FLA
MCA
2PE04703225
208/230-1-60
3/4
1075
1
7.8
5
6.3
10
3800
2PE04703246
460-1-60
3/4
1075
1
3.4
2.2
2.8
5
3800
2PE04703258
575-1-60
3/4
1050
1
2.9
1.5
1.9
4
3800
Belt drive blower systems MUST be adjusted to the
specific static and CFM requirements for the application.
The Belt drive blowers are NOT set at the factory for any
specific static or CFM. Adjustments of the blower speed
and belt tension are REQUIRED. Verify proper sheave
alignment; tighten blower pulley and motor sheave set
screws after these adjustments. Re-checking set screws
after 10-12 hrs. run time is recommended.
