507768-04P
Page 47 of 56
Issue 1933
High Altitude Information
NOTE:
In Canada, certification for installations at elevations over 4500 feet (1371 m) is the jurisdiction of local authorities.
Units may be installed at altitudes up to 10,000 ft. above sea level. See Table 11 for de-rate manifold values. Units installed
at altitude of 7501 - 10,000 feet require an orifice change. Units installed at altitudes of 4,501 - 10,000 feet (1371 -3048 m)
may require a pressure switch change which can be ordered separately.
Table 12 lists required pressure switch changes and orifice conversion kits at varying altitudes.
The combustion air pressure switches are factory set and require no adjustment.
Table 12.
Burner Orifice Conversion Kits at Varying Altitudes
Capacity
0-7,500 ft
(0-2,286m)
7,501 - 10,000 ft
(2,286 - 3,048 m)
Natural to LP/
Propane
LP/Propane to
Natural
High Altitude
Natural Burner
Orifice Kit
High Altitude LP/
Propane Burner
Orifice Kit
045
11K50+
73W80*
51W01
11K45+
070
090
110
* Conversion requires installation of a gas valve regulator spring which is provided with the gas conversion
kit.
+ LP Kits include low line pressure switch.
Pressure Switch Requirements at Varying Altitudes
Capacity
0 - 4500 ft
(0 - 1,371m)
4501 - 7500 ft
(1371 - 2286m)
7501 - 10000 ft
(2286 - 3048m)
045
No Change
No Change
11J09
070
No Change
17V95
11U67
090
No Change
11U70
10U93
110
No Change
11J12
10U93
Pressure switch is factory set. No adjustment necessary. All models use the factory-installed pressure switch
from 0-4500 feet (0-1371 m).
