York 251934-YTG-J-0910 Technical Manual page 67

Altitude/Temperature Correction Factors
Air
Temp. 0 1000
40 1.060 1.022
50 1.039 1.002
60 1.019 0.982
70 1.000 0.964
80 0.982 0.947
90 0.964 0.929
100 0.946 0.912
1.100
1.050
1.000
0.950
0.900
0.850
0.800
0.750
0.700
0.650
0.600
Gas Heat Minimum Supply Air
Size
(Tons)
180
(15)
210
(17.5)
240
(20)
300
(25)
For units with VFD and gas heat, the speed of the indoor
blower motor continues to be controlled by duct static
pressure via the VAV control board.
If there are VAV boxes present in the duct system,
the boxes must be driven to the full-open position
using a customer-supplied power source to assure
adequate airflow across electric heating elements
or gas heat exchanger tubes.
Johnson Controls Unitary Products
2000 3000
0.986 0.950
0.966 0.931
0.948 0.913
0.930 0.896
0.913 0.880
0.897 0.864
0.880 0.848
40 50
Heat Size
Min
24 4500
32 4500
24 6000
32 6000
24 6000
32 6000
24 7500
32 7500
Altitude (Ft.)
4000 5000 6000
0.916 0.882 0.849
0.898 0.864 0.832
0.880 0.848 0.816
0.864 0.832 0.801
0.848 0.817 0.787
0.833 0.802 0.772
0.817 0.787 0.758
60 70 80
Air Temperature (ºF)
Supply Air (CFM)
Cooling
Max Min
7000 4500
7000 4500
8750 6000
8750 6000
9400 6000
9400 6000
12500 7500
12500 7500
7000 8000
0.818 0.788
0.802 0.772
0.787 0.757
0.772 0.743
0.758 0.730
0.744 0.716
0.730 0.703
Sea Level
1000 ft
2000 ft
3000 ft
4000 ft
5000 ft
6000 ft
7000 ft
8000 ft
9000 ft
10000 ft
90 100
Heating
Max
7000
7000
8750
8750
9400
9400
12500
12500
251934-YTG-J-0910
9000 10000
0.758 0.729
0.743 0.715
0.729 0.701
0.715 0.688
0.702 0.676
0.689 0.663
0.676 0.651
67