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
CO
%
EL296
2
For Nat
Model
Low Fire
High Fire
045
5.4 - 6.4
7.5 - 8.5
070
5.3 - 6.3
7.4 - 8.4
090
5.8 - 6.8
7.6 - 8.6
110
6.1 - 7.1
8.0 - 9.0
135
6.1 - 7.1
7.8 - 8.8
The maximum carbon monoxide reading should not exceed 50 ppm.
EL296
0-4500 ft.
Gas
Unit
Low
Fire
Natural
1.7
All
LP/
Sizes
4.9
propane
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.
LP/Propane Conversion Kit and Pressure Switch Requirements at Varying Altitudes
Natural to
LP/Propane
EL296
Unit
0 - 7500 ft
(0 - 2286m)
-045
-070
-090
*78W93
-110
-135
* 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).
CO
%
2
For L.P
Low Fire
High Fire
6.4 - 7.4
8.8 - 9.8
6.3 - 7.3
8.7 - 9.7
6.8 - 7.8
8.9 - 9.9
7.1 - 8.1
9.3 - 10.3
7.1 - 8.2
9.1 - 10.1
Manifold and Supply Line Pressure 0-10,000ft.
Manifold Pressure in. wg.
4501-5500 ft.
5501-6500 ft.
High
Low
High
Fire
Fire
Fire
3.5
1.6
3.3
10.0
4.6
9.4
High Altitude
Natural Burner
Orifice Kit
7501 - 10,000 ft
(2286 - 3038m)
73W37
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
6501 - 7500ft.
Low
High
Low
High
Fire
Fire
Fire
Fire
1.5
3.2
1.5
4.4
9.1
4.3
TABLE 23
High Altitude
LP/Propane Burner
Orifice Kit
7501 - 10,000 ft
(2286 - 3038m)
*78W96
Page 59
Supply Line
7501 - 10000ft.
0 - 10000 ft.
Low
High
Min
Fire
Fire
3.1
1.7
3.5
4.5
8.9
4.9
10.0
11.0
High Altitude Pressure Switch
4501 - 7500 ft
7501 -10,000 ft
(1373 - 2286m)
(2286 - 3048m)
93W81
93W80
93W82
93W80
93W83
Pressure
in. w.g.
Max
13.0
13.0
93W84
93W85
93W80
93W85
93W85