Fan performance using accessory power exhaust, Altitude compensation, 240 performance data (cont) – Bryant 581A/B User Manual
Page 240
240
PERFORMANCE DATA (cont)
ALTITUDE COMPENSATION* — 581A155,180
(Natural Gas Units)
*Includes a 4% input reduction per each 1,000 feet.
†Orifices available through your Bryant dealer.
ALTITUDE COMPENSATION — 581A155,180
(LP Gas Units)
ALTITUDE COMPENSATION — 581A210-300
(Natural Gas)
ALTITUDE COMPENSATION — 581A210-300
(LP Gas)
ALTITUDE DERATING FACTOR*
*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 2000 ft.
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.
IMPORTANT: Local utility companies may be reducing heat content of
gas at altitudes above 2000 ft. If this is being done, changing spuds may
not be required.
EVAPORATOR-FAN MOTOR EFFICIENCY —
581A155,180
NOTE: All indoor-fan motors 5 hp and larger meet the minimum efficiency
requirements as established by the Energy Policy Act of 1992 (EPACT)
effective October 24, 1997.
ELEVATION
(ft)
NATURAL GAS ORIFICE SIZE†
Low Heat
High Heat
0-3,000
30
29
3,000- 7,000
31
30
7,000- 9,000
32
31
9,000-10,000
33
31
above 10,000
35
32
ELEVATION
(ft)
LIQUID PROPANE ORIFICE SIZE
Low Heat and High Heat
0-2,000
36
2,000
37
3,000
38
4,000
38
5,000
39
6,000
40
7,000
41
8,000
41
9,000
42
10,000
43
ELEVATION
(ft)
ORIFICE SIZE — NATURAL GAS
Low
Heat
Medium
Heat
High Heat
(6 Cell)
High Heat
(8 Cell)
0-2,000
29
30
29
29
2,000
29
30
29
29
3,000
30
31
30
30
4,000
30
31
30
30
5,000
30
31
30
30
6,000
30
31
30
30
7,000
31
32
31
31
8,000
31
32
31
31
9,000
31
32
31
31
above 10,000
32
33
32
32
Fan Performance Using Accessory
Power Exhaust (581A155,180)
a50-4028
ELEVATION
(ft)
ORIFICE SIZE — LP GAS
Low
Heat
Medium
Heat
High Heat
(6 Cell)
High Heat
(8 Cell)
0-2,000
35
38
35
35
2,000
36
39
36
36
3,000
36
39
36
36
4,000
37
40
37
37
5,000
37
40
37
37
6,000
38
41
38
38
7,000
39
42
39
39
8,000
40
43
40
40
9,000
41
44
41
41
above 10,000
42
45
42
42
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
MOTOR
HORSEPOWER
MOTOR EFFICIENCY
(%)
3.0
81.7
2.9, 3.7
85.8
5.0
87.5
581
A155
-3
00