Lennox ML296UH045XV36B - IV-HEATING SYSTEM SERVICE CHECKS; G- Proper Combustion

Page 45
NOTE- To obtain accurate reading, shut o all other gas
appliances connected to meter.
TABLE 18
GAS METER CLOCKING CHART
ML296
Unit
Seconds for One Revolution
Natural LP
1 cu ft
Dial
2 cu ft
Dial
1 cu ft
Dial
2 cu ft
Dial
-045 80 160 200 400
-070 55 110 136 272
-090 41 82 102 204
-110 33 66 82 164
Natural-1000 btu/cu ft LP-2500 btu/cu ft
IMPORTANT
For safety, shut unit o󰀨 and remove manometer as
soon as an accurate reading has been obtained.
Take care to replace pressure tap plug.
G- Proper Combustion
Furnace should operate minimum 15 minutes with correct
manifold pressure and gas ow rate before checking com-
bustion. See sections E- and F-. Take combustion sam-
ple beyond the ue outlet. TABLE 19 shows acceptable
combustions. The maximum carbon monoxide reading
should not exceed 100 ppm.
TABLE 19
ML296
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
The maximum carbon monoxide reading should not exceed 100ppm.
H- High Altitude
The manifold pressure, gas orice and pressure switch
may require adjustment or replacement to ensure prop-
er operation at higher altitudes. See TABLE 20 for gas
conversion and pressure switch kits. See TABLE 21 for
manifold pressures
TABLE 20
LP/Propane Conversion Kit and Pressure Switch Requirements at Varying Altitudes
Unit
Natural to
LP/Propane
High Altitude
Natural Burner
Orice Kit
High Altitude LP/
Propane Burner
Orice Kit
High Altitude Pressure Switch
0 - 7500 ft 7501 - 10,000 ft 7501 - 10,000 ft 4501 - 7500 ft 7501 - 10,000 ft
045
*11K51 73W37 *11K46
14A47 14A50
070 14A54 14A53
090 14A57 14A54
110 14A46 14A51
135 14A49 14A51
* 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).
TABLE 21
Manifold and Supply Line Pressure 0-10,000ft.
Unit Gas
Manifold Pressure in. wg. Supply Line
Pressure in. w.g
0 - 10,000 ft.
0 - 4500 ft 4501 - 5500 ft. 5501 - 6500 ft 6501 - 7500 ft 7501 - 10,000 ft
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
4.5 10.0 4.2 9.4 4.0 9.1 3.9 8.9 4.5 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.