Fan rpm at motor pulley setting, Altitude compensation, 127 performance data (cont) – Bryant 581A/B User Manual
Page 127

127
PERFORMANCE DATA (cont)
FAN RPM AT MOTOR PULLEY SETTING WITH STANDARD MOTOR* — 581B036-150
*Approximate fan rpm shown (standard motor/drive).
FAN RPM AT MOTOR PULLEY SETTING WITH HIGH-STATIC MOTOR* — 581B036-150
*Approximate fan rpm shown (high-static motor/drive).
ALTITUDE COMPENSATION* — 581B036-072
*As the height above sea level increases, there is less oxygen per cubic foot
of air. Therefore, the input rate should be reduced at higher altitudes.
†Orifices are available through your local Bryant distributor.
ALTITUDE COMPENSATION* — 581B090-150
*As the height above sea level increases, there is less oxygen per cubic foot
of air. Therefore, the input rate should be reduced at higher altitudes.
†Orifices are available through your local Bryant distributor.
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.
UNIT
581B
MOTOR PULLEY TURNS OPEN
0
1
/
2
1
1
1
/
2
2
2
1
/
2
3
3
1
/
2
4
4
1
/
2
5
5
1
/
2
6
036
1044
1008
971
935
898
862
826
789
753
716
680
—
—
048
1185
1144
1102
1061
1019
978
936
895
853
812
770
—
—
060
1460
1425
1389
1354
1318
1283
1248
1212
1177
1141
1106
1070
1035
072
1585
1538
1492
1445
1399
1352
1305
1259
1212
1166
1119
—
—
090,102
1085
1060
1035
1010
985
960
935
910
890
865
840
—
—
120
1080
1060
1035
1015
990
970
950
925
905
880
860
—
—
150
1130
1112
1087
1062
1037
1212
987
962
937
912
887
962
830
UNIT
581B
MOTOR PULLEY TURNS OPEN
0
1
/
2
1
1
1
/
2
2
2
1
/
2
3
3
1
/
2
4
4
1
/
2
5
5
1
/
2
6
036
1455
1423
1392
1360
1328
1297
1265
1233
1202
1170
1138
1107
1075
048
1455
1423
1392
1360
1328
1297
1265
1233
1202
1170
1138
1107
1075
060
1685
1589
1557
1525
1493
1460
1428
1396
1364
1332
1300
—
—
072
1685
1589
1557
1525
1493
1460
1428
1396
1364
1332
1300
—
—
090
1080
1025
1007
988
970
952
933
915
897
878
860
—
—
102
1080
1025
1007
988
970
952
933
915
897
878
860
—
—
120
1130
1112
1087
1062
1037
1212
987
962
937
912
887
962
830
ELEVATION
(ft)
72,000 AND 115,000/
60,000 and 90,000 BTUH
NOMINAL INPUT
150,000/120,000 BTUH
NOMINAL INPUT
Natural Gas
Orifice Size†
Liquid
Propane
Orifice Size†
Natural
Gas
Orifice Size
Liquid
Propane
Orifice Size†
0-2,000
33/38
43
30/32
38
2,000
34/39
43
30/33
39
3,000
35/40
44
31/34
40
4,000
36/41
44
32/35
41
5,000
36/41
44
33/35
42
6,000
37/42
45
34/36
43
7,000
37/42
45
35/37
43
8,000
38/43
46
36/37
44
9,000
39/43
47
37/38
44
10,000
41/44
48
38/40
45
11,000
43/45
48
39/41
45
12,000
44/45
49
40/42
46
13,000
44/46
49
41/43
47
14,000
45/47
50
42/43
47
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
ELEVATION
MAXIMUM HEATING VALUE (Btu/ft
3
)
0-2000
1100
2001-3000
1050
3001-4000
1000
4001-5000
950
5001-6000
900
5
81B0
36-
15
0