Bryant 579F User Manual
Page 62
APPLICATION DATA (cont)
ALTITUDE COMPENSATION* — 090-150 UNITS
ELEVATION
(Ft)
125,000, 180,000,
AND 224,000 BTUH
NOMINAL INPUT
250,000 BTUH
NOMINAL INPUT
Natural
Gas
Orifice
Size†
Liquid
Propane
Orifice
Size†
Natural
Gas
Orifice
Size†
Liquid
Propane
Orifice
Size†
0-2,000
31
41
30
38
2,000
32
42
30
39
3,000
32
42
31
40
4,000
32
42
32
41
5,000
33
43
33
42
6,000
34
43
34
43
7,000
35
44
35
43
8,000
36
44
36
44
9,000
37
45
37
44
10,000
38
46
38
45
11,000
39
47
39
45
12,000
40
47
40
46
13,000
41
48
41
47
14,000
42
48
42
47
*As the height above sea level increases, there is less oxygen per
cubic foot of air. Therefore, heat input rate should be reduced at
higher altitudes.
†Orifices available through your local distributor.
ALTITUDE COMPENSATION* — 180-300 UNITS
ELEVATION
(Ft)
NATURAL GAS
Orifice Size†
0-2,000
33
2,000
35
3,000
35
4,000
36
5,000
36
6,000
37
7,000
38
8,000
38
9,000
40
10,000
41
11,000
43
12,000
44
13,000
44
14,000
45
*As the height above sea level increases, there is less oxygen per cubic
foot of air. Therefore, heat input rate should be reduced at higher
altitudes.
†Orifices available through your local distributor.
ALTITUDE DERATING FACTOR* — ALL UNITS
ELEVATION
(Ft)
MAXIMUM HEATING VALUE
(Btu/ft
3
)
0-2,000
1,100
2,001-3,000
1,050
3,001-4,000
1,000
4,001-5,000
950
5,001-6,000
900
*Derating of the unit is not required unless the heating value of the gas
exceeds the values listed in the table above, or if the elevation exceeds
6000 ft. Derating conditions must be 4% per thousand ft above sea
level. For example, at 4000 ft, if the heating value of the gas exceeds
1000 Btu/ft
3
, the unit will require a 16% derating. For elevations above
6000 ft, the same formula applies. For example, at 7000 ft, the unit will
require a 28% derating of the maximum heating value per the National
Fuel Gas Code.
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