508134-01
Issue 2045
Page 46 of 56
Proper Combustion
Furnace should operate minimum 15 minutes with correct
manifold pressure and gas flow rate before checking
combustion. Take combustion sample beyond the flue
outlet and compare to Table 15.
Capacity
CO
2
% for Nat
CO
2
% for L.P.
All
7.2 - 9
8 - 10
The maximum carbon monoxide reading should not exceed
100 ppm.
Table 15.
High Altitude
NOTE:
In Canada, certification for installations at
elevations over 4500 feet (1372 m) is the jurisdiction of
local authorities.
Some units installed at altitude of 4501 - 10,000 feet (1373
to 3048 m) may require a pressure switch change which
can be ordered separately and a manifold de-rate. See
Table 16 or Table 17 for manifold pressures at all altitudes.
Table 18 lists conversion kit and Table 19 lists pressure
switch requirements at varying altitudes.
The combustion air pressure switch is factory-set and
requires no adjustment.
Unit
Fuel
Manifold
Pressure
Supply Line
All
Nat
3.5
4.5 - 13.0
All
LP/Propane
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 16. Supply Line and Manifold Pressure at All
Altitudes (inches w.c.) for -1 Through -3 Units
Capacity
Gas
Manifold Pressure in. w.g.
Supply Line Pressure
in. w.g.
0-10,000 ft.
0-4500 ft.
4501-5500 ft.
5501-6500 ft.
6501-7500 ft. 7501-10000 ft.
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 LP propane gas changeover kit is necessary to convert this unit. Refer to the changeover kit installation
instruction for the conversion procedure.
Table 17.
Manifold and Supply Line Pressure 0-10,000 ft.
Capacity
0 - 7,500 ft
(0 - 2,286 m)
7,501 - 10,000 ft
(2,286 - 3,048 m)
Natural to LP/Propane
LP/Propane to Natural
High Altitude
Natural Burner Orifice Kit
High Altitude
LP/Propane Burner
Orifice Kit
All
11K50+
73W80*
51W01
11K45+
* Conversion requires installation of a gas valve regulator spring which is provided with the gas conversion Kit.
+ LP Kits include low line pressure switch.
Table 18. Burner Orifice Conversion Kits at Varying Altitudes
Capacity
0 - 4500 ft
(0 - 1371m)
4501 - 7500 ft
(1371 - 2286m)
7501 - 10000 ft
(2286 - 3048m)
045
No Change
11U65
11U66
070
090
Pressure switch is factory set. No adjustment necessary. All models use the factory-installed pressure switch from 0-4500 feet (0-
1371 m).
Table 19. Pressure Switch at Varying Altitudes