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High Altitude Information
NOTE
− In Canada, certification for installations at eleva-
tions over 4500 feet (1372 m) is the jurisdiction of local au-
thorities.
The manifold pressure may require adjustment to ensure
proper operation at higher altitudes. Refer to table 11 for
proper manifold pressure settings at varying altitudes.
Table 12 lists required pressure switch changes and con-
version kits at varying altitudes.
The combustion air pressure switches are factory−set and
require no adjustment.
TABLE 11
Manifold Pressure (Outlet) inches w.c.
Fuel
Model
Input
Sizes
Altitude (feet)
0−
4500
4501−
5500
5501−
6500
6501−
7500
7501−
10,000
Nat.
Gas
All
sizes
3.5
3.5
3.5
3.5
3.5*
L.P.
Gas
All
sizes
10.0**
10.0**
10.0**
10.0**
10.0**
*Conversion kit required for applications at altitudes above 7501
ft. above sea level.
**Conversion kit required for applications at all altitudes.
NOTE
− A natural to L.P. propane gas changeover kit is nec-
essary to convert this unit. Refer to the changeover kit
installation instruction for the conversion procedure.
TABLE 12
Conversion Kit and Pressure Switch Requirements at Varying Altitudes
Input
High Altitude
Orifice Kit
Natural Gas Only
High Altitude Pressure
Switch Kit
LPG/Propane Kit
7501−10,000 ft.
4501−7500 ft.
7501−10,000 ft.
0−7500 ft.
7501−10,000 ft.
−045
44W51
− − −
95M22
83M74
83M75
−070
44W51
56M05
56M06
83M74
83M75
−090
44W51
75M20
56M07
83M74
83M75
−110
44W51
75M20
56M07
83M74
83M75
−135
44W51
56M04
60M35
83M74
83M75
Pressure switch is factory set. No adjustment necessary. All models use the factory installed pressure switch from 0−4500 feet (0−1370 m).
