Bryant 579F User Manual page 163

PERFECT HUMIDITY™ ADAPTIVE DEHUMIDIFICATION COIL PRESSURE DROP
ALTITUDE COMPENSATION* — 581C024-060
STANDARD UNIT
50,000 BTUH NOMINAL INPUT
ELEVATION
Natural Gas
(ft)
Orifice Size†
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 Bryant distributor.
PERFORMANCE DATA — 581C
Liquid Propane
Orifice Size†
43 49
44 50
44 50
44 50
45 51
45 51
46 51
47 52
47 52
48 52
49 53
50 54
51 55
52 56
ALTITUDE COMPENSATION* — 581C024-060
LOW NOx UNITS
60,000 AND 90,000 BTUH
NOMINAL INPUT
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 Bryant distributor.
ALTITUDE DERATING FACTOR*
ELEVATION
0-2000
2001-3000
3001-4000
4001-5000
5001-6000
*Derating of the gas heating equipment to compensate for the effects of alti-
tude is always required. Orifice change is not required if the fuel heating
value (at sea level) is below the limits listed in the table at left. Derating con-
ditions 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
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.
163
120,000 BTUH
NOMINAL INPUT
Natural Gas Natural Gas
Orifice Size† Orifice Size
38 32
40 33
41 35
42 36
43 37
43 38
44 39
45 41
46 42
47 43
48 44
49 44
50 46
51 47
MAXIMUM HEATING VALUE
AT SEA LEVEL (Btu/ft )
3
1100
1050
1000
950
900
, the unit will require a
3