Bryant 581J Natural Gas Supply Line Pressure Ranges, Unit Model Unit Size MIN MAX

581J

This unit is factory equipped for use with Natural Gas fuel at elevations up to 2000 ft (610 m) above sea level. Unit may be field converted for operation at elevations above 2000 ft (610 m) and/or for use with liquefied petroleum fuel. See accessory kit installation instructions regarding these accessories.

NOTE: Furance gas input rate on rating plate is for installation up to 2000 ft (610 m) above sea level. In U.S.A. the input rating for altitudes above 2000 ft (610 m) must be derated by 4% for each 1000 ft (305 m) above sea level. In Canada the input rating must be derated by 10% for altitudes of 2000 ft (610 m) to 4500 ft (1372 m) above sea level.

For natural gas applications, gas pressure at unit gas connection must not be less than 4 in. wg (996 Pa) or greater than 13 in. wg (3240 Pa) while the unit is operating. For liquified petroleum applications, the gas pressure must not be less than 11 in. wg (2740 Pa) or greater than 13 in. wg (3240 Pa) at the unit connection.

X

9” MINIMUM CLEARANCE

FOR PANEL REMOVAL

GAS

REGULATOR*

MANUAL GAS

SHUTOFF VALVE*

BASE UNIT

	48” MINIMUM
	DRIP LEG
BASE RAIL	PER NFGC*	FIELD-FABRICATED
	ROOF
		SUPPORT*
FROM	CURB
	LEGEND
GAS
METER	NFGC – National Fuel Gas Code

*Field supplied.

NOTE: Follow all local codes.

STEEL PIPE	SPACING OF SUPPORTS
NOMINAL DIAMETER	X DIMENSION
(in.)	(ft)
1/2	6
3/4 or 1	8
11/4 or larger	10

The gas supply pipe enters the unit at the burner access panel on the front side of the unit, through the long slot at

Fig. 15 - Gas Piping Guide

C11091

the bottom of the access panel. The gas connection to the unit is made to the 1/2-in. or 3/4-in. FPT gas inlet port on the unit gas valve.

Table 2 – Natural Gas Supply Line Pressure Ranges

UNIT MODEL	UNIT SIZE	MIN	MAX
581J	07, 08, 09, 12	4.0 in. wg	13.0 in. wg
		(996 Pa)	(3240 Pa)
!	CAUTION

EQUIPMENT DAMAGE HAZARD

Failure to follow this caution may result in damage to equipment.

When connecting the gas line to the unit gas valve, the installer MUST use a backup wrench to prevent damage to the valve.

Install a gas supply line that runs to the unit heating section. Refer to the NFPA 54/NFGC or equivalent code for gas pipe sizing data. Do not use a pipe smaller than the size specified. Size the gas supply line to allow for a maximum pressure drop of 0.5-in wg (124 Pa) between gas regulator source and unit gas valve connection when unit is operating at high-fire flow rate.

The gas supply line can approach the unit in three ways: horizontally from outside the unit (across the roof), thru-curb/under unit basepan (accessory kit required) or through unit basepan (factory-option or accessory kit required). Consult accessory kit installation instructions for details on these installation methods. Observe clearance to gas line components per Fig. 15.

(with Accessory Thru-the-Curb Service Connections)

Factory-Option Thru-Base Connections (Gas Connections) —

This service connection kit consists of a NPT gas adapter fitting, an electrical bulkhead connector and a 3/4-in electrical bulkhead connector, all factory-installed in the embossed (raised) section of the unit basepan in the condenser section.

LOW VOLTAGE

CONDUIT

CONNECTOR

HIGH VOLTAGE

CONDUIT

CONNECTOR

STAINLESS STEEL FITTING

C008621

Fig. 16 - Thru-Base Connection Fittings

The thru-base gas connector has male and female threads. The male threads protrude above the basepan of the unit; the female threads protrude below the basepan.

Check tightness of connector lock nuts before connecting gas piping.

Gas Line: Install a 1/2-in (08 & 09 size Low Gas units only) or 3/4-in (for all other units) NPT street elbow on the thru-base gas fitting. Attach an appropriate size pipe nipple with minimum length of 16-in (406 mm) (field-supplied) to the street elbow and extend it through the access panel at the gas support bracket. See Fig. 17.

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