Lennox SL280UHNV Series

Page 34
FIGURE 20
Operating Signal Pressure Measurement
TABLE 20
Unit
Production Resonance (more air) Difficulty Igniting (less air)
Orifice Size (Part No) Orifice Size Cat No Orifice Size Cat No
060 0.969 (08) 1.000 19X30 0.937 19X37
080 1.094 (07) 1.125 19X31 0.995 19X36
100 1.250 (06) 1.281 19X39 1.219 19X32
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 tables below. The maximum carbon
monoxide reading should not exceed 100 ppm.
TABLE 21
Firing Rate
CO
2
%
For Nat
CO
2
%
For LP
High Fire
6.0 - 7.8
7.5 - 9.9
Low Fire
The maximum carbon monoxide reading is 100 ppm.
H- High Altitude
Units are NOT approved for installations over 4500 ft