User Manual

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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