Bryant 581A/B Fan Performance Using Accessory Power Exhaust 579F180-300, Altitude Compensation

PERFORMANCE DATA — 579F (cont)

Fan Performance Using Accessory Power Exhaust (579F180-300)

ALTITUDE COMPENSATION* —

579F180-300

ELEVATION		NATURAL GAS ORIFICE SIZE†
(ft)		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

*Includes a 4% input reduction per each 1,000 feet. †Orifices available through your Bryant distributor.

ALTITUDE DERATING FACTOR*

ELEVATION (ft)	MAXIMUM HEATING VALUE
	(Btu/ft3)
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 2000 ft. For example, at 4000 ft, if the heating value of the gas exceeds 1000 Btu/ft3, 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, then changing spuds may not be required.

579F180-300

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