Lennox EL296UHV - Proper Combustion and Altitude Effects

Page 59
Proper Combustion
Furnace should operate minimum 15 minutes with correct
manifold pressure and gas flow rate before checking com
bustion. Take combustion sample beyond the flue outlet
and compare to the tables below.
TABLE 21
EL296
Model
CO
2
%
For Nat
CO
2
%
For L.P
Low Fire High Fire Low Fire High Fire
045 5.4 - 6.4 7.5 - 8.5 6.4 - 7.4 8.8 - 9.8
070 5.3 - 6.3 7.4 - 8.4 6.3 - 7.3 8.7 - 9.7
090 5.8 - 6.8 7.6 - 8.6 6.8 - 7.8 8.9 - 9.9
110 6.1 - 7.1 8.0 - 9.0 7.1 - 8.1 9.3 - 10.3
135 6.1 - 7.1 7.8 - 8.8 7.1 - 8.2 9.1 - 10.1
The maximum carbon monoxide reading should not exceed 50 ppm.
High Altitude Information
NOTE - In Canada, certification for installations at eleva
tions over 4500 feet (1372 m) is the jurisdiction of local au
thorities.
Units may be installed at altitudes up to 10,000 ft. above
sea level. See table 22 for de-rate manifold values. Units
installed at altitude of 7501 - 10,000 feet require an orifice
change. Units installed at altitude of 4501 - 10,000 feet re
quire a pressure switch change which can be ordered sep
arately. Table 23 lists conversion kit and pressure switch
requirements at varying altitudes.
The combustion air pressure switch is factory-set and re
quires no adjustment.
TABLE 22
Manifold and Supply Line Pressure 0-10,000ft.
EL296
Unit
Gas
Manifold Pressure in. wg.
Supply Line
Pressure
in. w.g.
0 - 10000 ft.
0-4500 ft. 4501-5500 ft. 5501-6500 ft. 6501 - 7500ft. 7501 - 10000ft.
Low
Fire
High
Fire
Low
Fire
High
Fire
Low
Fire
High
Fire
Low
Fire
High
Fire
Low
Fire
High
Fire
Min Max
All
Sizes
Natural 1.7 3.5 1.6 3.3 1.5 3.2 1.5 3.1 1.7 3.5 4.5 13.0
LP/
propane
4.9 10.0 4.6 9.4 4.4 9.1 4.3 8.9 4.9 10.0 11.0 13.0
NOTE - A natural to L.P. propane gas changeover kit is necessary to convert this unit. Refer to the changeover kit installation instruction for the conversion
procedure.
TABLE 23
LP/Propane Conversion Kit and Pressure Switch Requirements at Varying Altitudes
EL296
Unit
Natural to
LP/Propane
High Altitude
Natural Burner
Orifice Kit
High Altitude
LP/Propane Burner
Orifice Kit
High Altitude Pressure Switch
0 - 7500 ft
(0 - 2286m)
7501 - 10,000 ft
(2286 - 3038m)
7501 - 10,000 ft
(2286 - 3038m)
4501 - 7500 ft
(1373 - 2286m)
7501 -10,000 ft
(2286 - 3048m)
-045
*78W93 73W37 *78W96
93W81 93W84
-070 93W80 93W85
-090 93W82 93W80
-110 93W80 93W85
-135 93W83 93W85
* Conversion requires installation of a gas valve manifold spring which is provided with the gas conversion kit.
Pressure switch is factory set. No adjustment necessary. All models use the factory-installed pressure switch from 0-4500 feet (0-1370 m).