6
Table 2 - NATURAL GAS
MODEL 90-50
Stock Factory
Btu Value of Natural Gas++
Settings
750
850
950
1000
1050
Altitude in Ft.
0-5,000
5,000-10,000
Normal Input (MBH)
50
–
–
–
–
–
Combustion Setting (CO
2
)
8.7 - 9.7% (CO
<
100 ppm)
Orifice
43331094
43331094
MODEL 90-75
Stock Factory
Btu Value of Natural Gas++
Settings
750
850
950
1000
1050
Altitude in Ft.
0-5,000
5,000-10,000
Normal Input (MBH)
75
–
–
–
–
–
Combustion Setting (CO
2
)
8.7 - 9.7% (CO
<
100 ppm)
Orifice
43331092
43331092
MODEL 90-100 /
Stock Factory
Btu Value of Natural Gas++
Settings
750
850
950
1000
1050
Altitude in Ft.
0-5,000
5,000-10,000
Normal Input (MBH)
100
–
–
–
–
–
Combustion Setting (CO
2
)
8.7 - 9.7% (CO
<
100 ppm)
Orifice
43331090
43331090
++Contact local gas utility or distributor for Btu value of gas.
BOILERS FOR USE AT HIGH ALTITUDE - UNITED STATES INSTALLATIONS
• Boilers (with exception of 90-75 propane (LP) product)
are factory equipped for operation at altitudes ranging
from 0-10,000 feet above sea level.
• No changes to factory settings are required for
installations from 0-5,000 feet above sea level.
• For altitudes from 5,000-10,000 feet above sea level
gas manifold pressure needs to be adjusted based upon
calorific (Btu) value of supply gas (contact local gas
utility or distributor for this value).
•
For specific settings refer to Table 2 for natural gas
applications and Table 3, Page 7 for propane (LP) gas
applications.
•
Instructions on how to adjust gas manifold pressure
settings see Figure 25 and Figure 26, Page 44.
Note 90-75 propane (LP) applications for 5,000 - 10,000
feet above sea level require orifice change as well as gas
manifold pressure adjustment based upon calorific (Btu)
value of supply gas.
Refer to Table 2
and Table 3 for high altitude orifice
part numbers. For replacing an orifice refer to specific
instructions included with conversion kit.
