Page 47
TABLE 19
Supply Line and Manifold Pressure (inches w.c.) At
All Altitudes For -1 Through -5 Units
Unit
Fuel
Manifold Pres
sure
Line
Pressure
All
Nat. Gas
3.5
4.5 - 13.0
All
L.P. Gas
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.
E-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 tables below.
TABLE 20
ML195
Unit
CO
2
%
For Nat
CO
2
%
For L.P.
-045
7.2 - 8.2
8.6 - 9.6
-070
-090
-110
-135
The maximum carbon monoxide reading should not exceed 50 ppm.
F-High Altitude
NOTE
- In Canada, certification for installations at eleva
tions over 4500 feet (1372 m) is the jurisdiction of local au
thorities.
ML195UH-1 through -5 units require no manifold pressure
adjustments for operation at altitudes up to 10,000 feet
(3048 m) above sea level. However, -6 units and later
installed at altitude of 4501 - 10,000 feet (1373 to 3048m)
require a pressure switch change which can be ordered
separately and a manifold pressure de-rate. See table 19
or table 21 for manifold pressuers at varying altitudes.
Table 22 lists conversion kit and pressure switch require
ments at varying altitudes.
The combustion air pressure switch is factory-set and re
quires no adjustment.
TABLE 21
Manifold and Supply Line Pressure 0-10,000ft. For -6 Units and Later
ML195
Unit
Gas
Manifold Pressure in. wg.
Supply Line Pressure
in. w.g.
0 - 10000 ft.
0-4500 ft.
4501-5500 ft.
5501-6500 ft.
6501 - 7500ft.
7501 - 10000ft.
All Sizes
Natural
3.5
3.3
3.2
3.1
3.5
4.5
13.0
LP/propane
10.0
9.4
9.1
8.9
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.
TABLE 22
Conversion Kit and Pressure Switch Requirements at Varying Altitudes
* 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).
ML195
Unit
Natural to
LP/Propane
High Altitude
Natural Burner
Orifice Kit
High Altitude
LP/Propane Burner
Orifice Kit
High Altitude Pressure Switch
0 - 7500 ft
(0 - 2286m)
7501 - 10,000 ft
(2286 - 3038m)
7501 - 10,000 ft
(2286 - 3038m)
4501 - 7500 ft
(1373 - 2286m)
7501 -10,000 ft
(2286 - 3048m)
-045
*69W73
73W37
*68W68
No Change
93W87
-070
93W93
93W86
-090
93W92
93W86
-110
93W93
93W86
-135
93W92
93W86
