York ZT SERIES - RPM Selection; Indoor Blower Specifications; Air Balance; Checking Air Quantity

6021980-UIM-A-1120
56 Johnson Controls Ducted Systems
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.
2. Insert eight-inches of 1/4 inch metal tubing into the airflow
on both sides of the indoor coil.
Note: You must insert the tubes and hold them in a position
perpendicular to the air flow so that velocity pressure
does not affect the static pressure readings.
3. Use an inclined manometer or Magnehelic® to determine
the pressure drop across a dry evaporator coil. The
moisture on an evaporator coil can vary greatly, measuring
the pressure drop across a wet coil under field conditions
could be inaccurate. To ensure that the coil is dry, de-
activate the compressors de-activated while the test is
being run.
Note: De-energize the compressors before you take any test
measurements to ensure that the evaporator coil is dry.
Table 21: RPM selection
Size
(tons)
Model Airflow option 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
078
(6.5)
ZT
Standard 1.5 1.725 1VL40 AK74 N/A 663 713 759 803 840 882
High static 2 2.3 1VM50 AK74 N/A 884 927 977 1025 1074 1121
090
(7.5)
ZT
Standard 1.5 1.725 1VL40 AK69 N/A 714 761 799 852 905 955
High static 3 3.45 1VM50 AK69 N/A 952 1002 1043 1104 1140 1202
102
(8.5)
ZT
Standard 2 2.3 1VM50 AK89 N/A 737 775 812 851 889 926
High static 3 3.45 1VM50 AK74 N/A 903 943 985 1028 1071 1113
120
(10)
ZT
Standard 2 2.3 1VM50 AK84 N/A 781 819 859 897 932 969
High static 3 3.45 1VM50 AK74 N/A 903 943 985 1028 1076 1113
150
(12.5)
ZT
Standard 3 3.45 1VM50 AK74 N/A 908 955 1003 1049 1094 1142
High static 5 5.75 1VP56 BK77 1104 1102 1157 1200 1246 1282 1328
Table 22: 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
078
(6.5)
ZT
Standard 1-1/2 1725 0.8 1.15 56 2.6 - 3.6 7/8 1VL40 7.0 1 AK74
High static 2 1725 0.8 1.15 56 3.6 - 4.6 7/8 1VM50 6.0 1 AK74
090
(7.5)
ZT
Standard 1-1/2 1725 0.8 1.15 56 2.6 - 3.6 7/8 1VL40 7.0 1 AK69
High static 3 1725 0.8 1.15 56 3.6 - 4.6 7/8 1VM50 5.7 1 AK69
102
(8.5)
ZT
Standard 2 1725 0.8 1.15 56 3.4 - 4.4 7/8 1VM50 9.0 1 AK89
High static 3 1725 0.8 1.15 56 3.4 - 4.4 7/8 1VM50 7.0 1 AK74
120
(10)
ZT
Standard 2 1725 0.8 1.15 56 3.4 - 4.4 7/8 1VM50 8.0 1 AK84
High static 3 1725 0.8 1.15 56 3.4 - 4.4 7/8 1VM50 7.0 1 AK74
150
(12.5)
ZT
Standard 3 1725 0.8 1.15 56 3.4 - 4.4 7/8 1VM50 7.0 1 AK74
High static 5 1725 0.87 1.15 184T 4.3 - 5.3 1-1/8 1VP56 6.7 1 BK77
Table 23: Power exhaust specifications
Model Voltage
Motor Unit (per circuit)
Fuse size CFM @ 0.1 ESP
HP RPM
1
1. Motors are multi-tapped and factory wired for high speed.
QTY LRA FLA MCA
2PE04704706 208/230-1-60 3/4 1075 1 24.9 5 6.3 10 4800
2PE04704746 460-1-60 3/4 1075 1 N/A 2.2 2.8 5 4800
2PE04704758 575-1-60 3/4 1050 1 N/A 1.5 1.9 4 4800
You must adjust the belt drive blower systems 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. You must adjust the blower speed
and belt tension.
Verify proper sheave alignment. Tighten the blower
pulley and motor sheave set screws after these
adjustments. Re-check the set screws after 10-12 hours
of run time.