User's Manual

1068152-YTG-L-0815
Johnson Controls Unitary Products 75
Drive Selection
1. Determine side or bottom supply duct Application.
2. Determine desired airflow.
3. Calculate or measure the amount of external static pressure.
• Add or deduct any additional static resistance from “Additional Static Resistance Table”.
4. Using the operating point determined from steps 1, 2 & 3, locate this point on the appropriate supply air blower performance
table. (Linear interpolation may be necessary.)
5. Noting the RPM and BHP from step 4, locate the appropriate motor and, or drive on the RPM selection table.
6. Review the BHP compared to the motor options available. Select the appropriate motor and, or drive.
7. Review the RPM range for the motor options available. Select the appropriate drive if multiple drives are available for the
chosen motor.
8. Determine turns open to obtain the desired operation point.
Example
1. 3400 CFM
2. 1.6 iwg
3. Using the airflow performance table below, the following data point was located: 1039 RPM & 2.52 BHP.
4. Using the RPM selection table below, Model ZY and Size 08 (Tons) 7.5 is found.
5. 2.59 BHP exceeds the maximum continuous BHP rating of the 1.5 HP motor. The 3 HP motor is required.
6. 1039 RPM is within the range of the 3 HP drives.
7. Using the 3 HP motor and drive, 1.5 turns open will achieve 1039 RPM.
Airflow Performance
Example Supply Air Blower Performance
ZY08 (7.5 Ton) Bottom Duct
CFM
Available External Static
0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0
RPM BHP RPM BHP RPM BHP RPM BHP RPM BHP RPM BHP RPM BHP RPM BHP RPM BHP RPM BHP
2250
556 0.45 621 0.65 683 0.83 742 1.00 798 1.18 852 1.34 904 1.51 954 1.69 1003 1.87 1050 2.06
2400
567 0.53 632 0.73 694 0.91 753 1.09 809 1.26 863 1.43 914 1.60 964 1.77 1013 1.95 1060 2.14
2600
580 0.65 646 0.85 707 1.03 766 1.21 823 1.38 876 1.55 928 1.72 978 1.89 1027 2.07 1074 2.27
2800
595 0.79 660 0.99 722 1.17 780 1.35 837 1.52 890 1.69 942 1.86 992 2.03 1041 2.21 1088 2.40
3000
609 0.94 674 1.14 736 1.32 795 1.50 851 1.67 905 1.83 957 2.00 1007 2.18 1056 2.36 1100 2.55
3200
625 1.10 690 1.30 752 1.48 810 1.66 867 1.83 921 2.00 972 2.17 1022 2.34 1071 2.52 -- --
3400
641 1.28 706 1.47 768 1.66 827 1.83 883 2.00 937 2.17 989 2.34 1039 2.52 1087 2.70 '-- --
Standard Static Option with Motor rated at 2.4-hp
Medium Static Option with Motor rated at 2.4-hp
High Static Option with Motor rated at 3.7-hp
--
Exceeds recommended blower speed
Example RPM Selection
Model
Size
(Tons)
Airflow
Option
HP
Max
BHP
Blower
Sheave
Motor
Sheave
6 Turns
Open
5 Turns
Open
4 Turns
Open
3 Turns
Open
2 Turns
Open
1 Turns
Open
Fully
Closed
ZY
08
(7.5)
Std. 1.5 2.4 AK74 1VL34 N/A 475 525 575 625 675 725
Med. 1.5 2.4 AK74 1VL44 N/A 700 750 800 850 900 950
H. Static 3.0 3.7 AK74 1VP50 N/A 850 900 950 1000 1050 1100