High Altitude Information - Lennox G51MP SERIES Installation Instructions Manual

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.
Conversion Kit and Pressure Switch Requirements at Varying Altitudes
High Altitude
Orifice Kit
Input
Natural Gas Only
7501−10,000 ft.
−045
−070
−090
−110
−135
Pressure switch is factory set. No adjustment necessary. All models use the factory installed pressure switch from 0−4500 feet (0−1370 m).
High Altitude Pressure
4501−7500 ft.
44W51 − − −
44W51 56M05
44W51 75M20
44W51 75M20
44W51 56M04
Manifold Pressure (Outlet) inches w.c.
Model
Fuel Input
Sizes
4500
Nat. All
3.5
Gas sizes
L.P. All
10.0**
Gas sizes
*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
Switch Kit
7501−10,000 ft.
95M22
56M06
56M07
56M07
60M35
Page 41
TABLE 11
Altitude (feet)
0− 4501− 5501− 6501−
5500 6500 7500
3.5 3.5 3.5
10.0** 10.0** 10.0**
LPG/Propane Kit
0−7500 ft. 7501−10,000 ft.
83M74
83M74
83M74
83M74
83M74
7501−
10,000
3.5*
10.0**
83M75
83M75
83M75
83M75
83M75