Lennox SL280DFNV Series Unit Information page 31

Production
Unit
Orifice Size (Part No)
-060 0.969 (08)
-080 1.094 (07)
G- Proper Combustion
Furnace should operate a minimum 15 minutes with cor-
rect manifold pressure and gas flow rate before check-
ing combustion. Take combustion sample beyond the flue
outlet and compare to TABLE 21. The maximum carbon
monoxide reading should not exceed 100 ppm.
TABLE 21
Firing Rate CO % For Natural
2
High Fire
Low Fire
Operating Signal Pressure Measurement
Resonance (more air)
Orifice Size
1.000
1.125
CO % For LP
2
6.0 - 7.8 7.5-9.9
FIGURE 20
TABLE 20
Cat No
19X30
19X31
H- High Altitude
Units may be installed at altitudes up to 7,500 ft. above
sea level. See TABLE 18 and TABLE 19 for de-rate man-
ifold values. Units installed at altitude of 4501 - 7,500 feet
require a pressure switch change which can be ordered
separately. TABLE 22 lists pressure switch requirements
at high altitude.
The combustion air pressure switch is factory-set and re-
quires no adjustment.
Unit
-060
-080
-100
Page 31
Difficulty Igniting (less air)
Orifice Size Cat No
0.937 19X37
0.995 19X36
TABLE 22
Pressure Switch 4501-7500ft
Natural LP/Propane
20K91 No Change
No Change N/A