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31-5000729 Rev. 0
Gas Flow (Approximate)
Gas Meter Clocking Chart
Capacity
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
Natural - 1000 btu/cu ft
LP - 2500 btu/cu ft
Table 15.
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 16.
Capacity
CO
2
% for Nat
CO
2
% for L.P.
All
7.2 - 8.2
8.6 - 9.6
The maximum carbon monoxide reading should not exceed
100 ppm.
Table 16.
High Altitude
NOTE:
In Canada, certification for installations at elevations
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 14 for de-rate manifold values. Units
installed at altitude of 7501 - 10,000 feet require an orifice
change. Units installed at altitudes of 4501 - 10,000 feet (1373
to 3048 m) require a pressure switch change which can be
ordered separately. Table 17 and Table 18 list conversion kit
and pressure switch requirements at varying altitudes.
The combustion air pressure switch is factory-set and
requires no adjustment.
Capacity
0 - 7,500 ft
(0 - 2,286 m)
7,501 - 10,000 ft
(2,286 - 3048m)
Natural to LP/Propane
High Altitude Natural Burner
Orifice Kit
High Altitude LP/Propane
Burner Orifice Kit
All
11K50
†
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 17.
Burner Orifice Conversion Kits at Varying Altitudes
Capacity
0 - 4,500 ft.
(0 - 1,373 m)
4,501 - 7,500 ft.
(1,371 - 2,286 m)
7,501 - 10,000 ft
(2,286 - 3,048 m)
045
No Change
11U65
11U66
070
11U70
11U68
090
11U70
10U93
Pressure switch is factory set. No adjustment necessary. All models use the factory-installed pressure switch from 0-4,500 feet (0-
1,370 m).
Table 18. Pressure Switch Requirements at Varying Altitudes