High Altitude - Lennox LGM Series Manual

SP EC IFIC ATIONS
Number of Gas Heat Stages
Gas Heating Input - Btuh
Performance
Output - Btuh
Recommended Gas Supply Pressure - Nat. / LPG
Gas Supply Pressure Range
HIG H A LTITUD E D ERATE
Units may be installed at altitudes up to 2000 feet above sea level without any modification.
At altitudes above 2000 feet, units must be derated to match gas manifold pressures shown in table below.
At altitudes above 4500 feet unit must be derated 2% for each 1000 feet above sea level.
NOTE − This is the only permissible derate for these units.
Gas Heat Altitude
Type Feet
Standard 2001-4500
Medium 2001-4500
High 2001-4500
Heat Input Type
First Stage
Second Stage
Second Stage
Temperature Rise Range - °F
Minimum Air Volume - cfm
Thermal Efficiency
Gas Supply Connections
Min./Max. (Natural)
Min./Max. (LPG)
Gas Manifold Pressure
in. w.g.
Natural Gas
3.4
3.4
3.4
Standard
2
84,500
130,000
104,000
15 - 45
2150
80%
3/4 in. NPT
7 in. w.g. / 11 in. w.g.
LPG/Propane Gas
9.6
9.6
9.6
Page 6
Medium
2
117,000
180,000
144,000
30 - 60
2250
80%
3/4 in. NPT
4.7 - 10.5 in. w.g.
10.8 - 13.5 in. w.g.
Input Rate - Btuh
(Natural Gas or LPG/Propane)
First Stage Second Stage
84,500
117,000
156,000
G A S HEAT
High
2
156,000
240,000
192,000
40 - 70
2600
80%
3/4 in. NPT.
124,000
172,000
230,000