Altitude Compensation; Altitude Derating Factor - Bryant COMMERCIAL SINGLE PACKAGE ROOFTOP GAS HEAT/ELECTRIC COOLING 581B User Manual

ALTITUDE COMPENSATION*

581B036-072
72,000 AND 115,000/
60,000 and 90,000
BTUH NOMINAL
ELEVATIO
INPUT*
N
Natural
(ft)
Gas Propane
Orifice
Size†
0-2,000 33/38
2,000 34/39
3,000 35/40
4,000 36/41
5,000 36/41
6,000 37/42
7,000 37/42
8,000 38/43
9,000 39/43
10,000 41/44
11,000 43/45
12,000 44/45
13,000 44/46
14,000 45/47
*
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 Bryant distributor.
PERFORMANCE DATA (cont)
150,000/120,000 BTUH
NOMINAL INPUT
Liquid Natural Liquid
Gas Propane
Orifice Orifice Orifice
Size† Size† Size†
43/45 30/32 38/42
43/46 30/33 39/42
44/47 31/34 40/43
44/47 32/35 41/43
44/48 33/35 42/43
45/48 34/36 43/44
45/49 35/37 43/44
46/49 36/37 44/45
47/50 37/38 44/46
48/50 38/40 45/47
48/51 39/41 45/48
49/51 40/42 46/49
49/52 41/43 47/49
50/52 42/43 47/50

ALTITUDE DERATING FACTOR*

ELEVATION
0-2000
2001-3000
3001-4000
4001-5000
5001-6000
*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
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.
ALTITUDE COMPENSATION*
125,000-224,000 BTUH
ELEVATION
(ft)
0-2,000
2,000
3,000
4,000
5,000
6,000
7,000
8,000
9,000
10,000
11,000
12,000
13,000
14,000
*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 Bryant distributor.
581B036-150
MAXIMUM HEATING VALUE
(Btu/ft 3 )
1100
1050
1000
950
900
3 , the unit will require a 16% derating. For
44
581B090-150
NOMINAL INPUT NOMINAL INPUT
Natural Liquid Natural
Gas Propane Gas
Orifice Orifice Orifice
Size† Size† Size†
31 41 30
32 42 30
32 42 31
32 42 32
33 43 33
34 43 34
35 44 35
36 44 36
37 45 37
38 46 38
39 47 39
40 47 40
41 48 41
42 48 42
250,000 BTUH
Liquid
Propane
Orifice
Size†
38
39
40
41
42
43
43
44
44
45
45
46
47
47