25
gas. The gas heating value based on sea level
can be obtained from your local gas utility. The
heating value of gas at high altitude is always
lower than the sea level heating value. The
heating values used in Tables 6 & 7 are based
on sea level values.
Natural Gas High Altitude Conversion
All factory shipped furnaces are ready to oper-
ate between zero and 4999 ft. above sea level.
For higher altitudes (between 5000 and 10,000
ft. above sea level), conversion can be achieved
simply by adjusting the furnace manifold pres-
sure as shown in Table 6.
LP/Propane Gas Conversion
IMPORTANT NOTE: When converting a low
NOx furnace from Natural gas to LP/pro-
pane gas, it is necessary to remove the NOx
Baffles from the furnace.
Conversion of this furnace to utilize LP/propane
gas must be made by qualified service person-
nel, using factory authorized or approved parts.
Conversion to LP/propane gas can be accom-
plished by first replacing the natural gas orifices
with the appropriate LP/propane orifices shown
in Table 8 or 9. Note: for installations between
Table 8. Natural and LP Gas Orifice Sizes
for Elevations between zero and 4999 ft.
Above Sea Level
Table 9. Natural and LP gas Orifice Sizes
for Elevations between 5000 and 10,000
ft. Above Sea Level
Furnace Rating
Furnace Rating
Plate Input (Btu/h)
Nat
LP
Plate Input (Btu/h)
Nat
LP
60,000 45
55
60,000 45
56
72,000 43
54
72,000 43
55
96,000 43
54
96,000 43
55
120,000 43
54
120,000 43
55
Orifice Drill Size
Orifice Drill Size
For a LP Gas Sea Level Heating Value of 2,500 Btu/hr.
Elevation (feet above sea level)
zero to
1999
2000 to
4999
5000 to
5999
6000 to
7999
8000 to
10000
Manifold Pressure Setting (in WC)
Full Input
10
8.5
10
9
8.5
Low Input
5.5
5.5
6.5
6.5
6.5
Table 6. Manifold Pressure (in WC) for Natural Gas at Various Altitudes
Table 7. Manifold Pressure (in WC) for LP/Propane Gas at Various Altitudes
For a Natural Gas Sea Level Heating Value of 800 to 899 Btu/cu.ft.
Elevation (feet above sea level)
zero to
1999
2000 to
4999
5000 to
5999
6000 to
7999
8000 to
10000
Manifold Pressure Setting (in WC)
Full Input
3.5
3.5
3.5
3.5
3.0
Low Input
1.7
1.7
1.7
1.7
1.6
For a Natural Gas Sea Level Heating Value of 900 to 999 Btu/cu.ft.
Elevation (feet above sea level)
zero to
1999
2000 to
4999
5000 to
5999
6000 to
7999
8000 to
10000
Manifold Pressure Setting (in WC)
Full Input
3.5
3.5
3.5
3.2
2.8
Low Input
1.7
1.7
1.7
1.6
1.5
For a Natural Gas Sea Level Heating Value of 1,000 to 1,100 Btu/cu.ft.
Elevation (feet above sea level)
zero to
1999
2000 to
4999
5000 to
5999
6000 to
7999
8000 to
10000
Manifold Pressure Setting (in WC)
Full Input
3.5
3.5
3
2.8
2.5
Low Input
1.7
1.7
1.5
1.4
1.3
Summary of Contents for TA-060C-08A
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