Lennox SL280DF060NV36B Instruction Manual page 31

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