Proper Combustion; High Altitude - Lennox MERIT Series Installation Instructions Manual

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 table below. The maximum carbon
monoxide reading should not exceed 100 ppm.
TABLE 15
ML193 Unit
045
070
090
The maximum carbon monoxide reading should not exceed 100 pm.
ML193E
Gas
Unit
Natural
All
Sizes
L.P. 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.
Conversion Kit and Pressure Switch Requirements at Varying Altitudes
Natural to LP/
Propane
ML193E Unit
0 - 7500 ft
(0 - 2286m)
-045
-070 *11K49
-090
* 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).
Nat LP
CO CO
2 2
7.0 - 9.0 8.0 - 10.0
Manifold and Supply Line Pressure 0-10,000ft.
0 - 4500 ft 4501 - 5500 ft
3.5 3.3
10.0 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
authorities.
Units may be installed at altitudes up to 10,000 ft. above
sea level. See TABLE 16 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
require a pressure switch change which can be ordered
separately. TABLE 17 lists conversion kit and pressure
switch requirements at varying altitudes.
The combustion air pressure switch is factory-set and re-
quires no adjustment.
NOTE - A natural to LP/propane gas changeover kit is
necessary to convert this unit. Refer to the changeover kit
installation instruction for the conversion procedure.
TABLE 16
Manifold Pressure in. wg.
5501 - 6500 ft 6501 - 7500 ft
3.2 3.1
9.1 8.9
TABLE 17
High Altitude LP/
LP/Propane to
Propane Burner
Natural
Orifice Kit
0 - 7500 ft 7501 - 10,000 ft
(0 - 2286m) (2286 - 3038m)
*73W81 *11K44
Page 39
Supply Line Pressure
in. w.g.
7501 - 10,000
0 - 10000 ft.
ft
3.5 4.5
10.0 11.0
High Altitude Pressure Switch
4501 - 7500 ft 7501 -10,000 ft
(1373 - 2286m) (2286 - 3048m)
11U65
13.0
13.0
11U66