Bryant 580J*04--12 appendix Gas Heating System, Control Circuit, Fuel Types and Pressures, General

Control Circuit, 24-V

The control circuit is protected against overcurrent conditions by a circuit breaker mounted on control transformer TRAN. Reset is manual.

GAS HEATING SYSTEM

580J unit heating systems are referenced here according to unit Gas Heat Option (defined in the unit model number Position#8) and Heat Level (input capacity, defined in Positions #9-10-11). See Appendix 1 for a complete unit model number nomenclature chart.

POSITION #8 GAS HEAT OPTION

ANat. Gas / Standard HX and Heat

BNat. Gas / SS HX and Low NOx Heat

CNat. Gas / SS HX and Standard Heat

General

The heat exchanger system consists of a gas valve feeding multiple inshot burners off a manifold. The burners fire into matching primary tubes. The primary tubes discharge into combustion plenum where gas flow converges into secondary tubes. The secondary tubes exit into the induced draft fan wheel inlet. The induced fan wheel discharges into a flue passage and flue gases exit out a flue hood on the side of the unit. The induced draft fan motor includes a Hall Effect sensor circuit that confirms adequate wheel speed via the Integrated Gas Control (IGC) board. Safety switches include a Rollout Switch (at the top of the burner compartment) and a limit switch (mounted through the fan deck, over the tubes). (See Fig. 27 and Fig. 28.)

INDUCED-	ROLLOUT
DRAFT	SWITCH
MOTOR
MOUNTING
PLATE
BURNER
SECTION	FLUE
	EXHAUST
	VESTIBULE
INDUCED-	PLATE
DRAFT	BLOWER
MOTOR
	HOUSING
MANIFOLD	GAS
PRESSURE
TAP	VALVE

C06152

Fig. 27 - Burner Section Details

Limit Switch

and Shield

C08284

Fig. 28 - Limit Switch Location

Fuel Types and Pressures

Natural Gas — The 580J unit is factory-equipped for use with Natural Gas fuel at elevation under 2000 ft (610 m). See section Orifice Replacement for information in modifying this unit for installation at elevations above 2000 ft (610 m).

Gas line pressure entering the unit’s main gas valve must be within specified ranges. Adjust unit gas regulator valve as required or consult local gas utility.

Table 4 – Natural Gas Supply Line Pressure Ranges

580J SIZE	GAS	HEAT	MIN	MAX
	HEAT OPT	LEVEL
All	All	All	4.0 in. wg	13.0 in. wg
			(996 Pa)	(3240 Pa)

Manifold pressure is factory-adjusted for NG fuel use. Adjust as required to obtain best flame characteristic.

Table 5 – Natural Gas Manifold Pressure Ranges

GAS	HEAT	HIGH	LOW
HEAT				RANGE
	LEVEL	FIRE	FIRE
OPT
A, C	All	3.5 in. wg	1.7 in. wg	2.0--- 5.0 in. wg (Hi)
		(872 Pa)	(423 Pa){	(498--- 1245 Pa)
B	All	3.5 in. wg	NA	2.0--- 5.0 in. wg (Hi)
		(872 Pa)		(498--- 1245 Pa)

NA: Not Available

{3 Phase models only

Liquid Propane — Accessory packages are available for field-installation that will convert the 580J unit (except low NOx model) to operate with Liquid Propane (LP) fuels. These kits include new orifice spuds, new springs for gas valves and a supply line low pressure switch. See section on Orifice Replacement for details on orifice size selections.

Low NOx models include specially-sized orifices and use of different flue flow limits and tube baffles. Because of these extra features, conversion of these models to LP is not recommended.

Fuel line pressure entering unit gas valve must remain within specified range.

580J

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