Carrier 48TC**16 Install Gas Piping, Natural Gas Supply Line Pressure Ranges

Step 10 — Install Gas Piping

Installation of the gas piping must be accordance with local building codes and with applicable national codes. In U.S.A., refer to NFPA 54/ANSI Z223.1 National Fuel Gas Code (NFGC). In Canada, installation must be accordance with the CAN/CSA B149.1 and CAN/CSA B149.2 installation codes for gas burning appliances.

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: 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.

			X
	9” MINIMUM CLEARANCE
	FOR PANEL REMOVAL
				GAS	FROM
				REGULATOR*	GAS
		MANUAL GAS			METER
		SHUTOFF VALVE*
BASE UNIT

48” MINIMUM

DRIP LEG

PER NFGC* BASE RAIL

ROOF				FIELD-
				FABRICATED
CURB
				SUPPORT*
		LEGEND
	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

For natural gas applications, gas pressure at unit gas connection must not be less than 5 in. wg (1250 Pa) or greater than 13 in. wg (3240 Pa) while the unit is operating. For liquified petroleum applications, the gas pressure must

Fig. 16 - Gas Piping Guide

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

C11121

48TC**16

not be less than 11 in. wg (2740 Pa) or greater than 13 in. wg (3240 Pa) at the unit connection.

The gas supply pipe enters the unit at the burner access panel on the front side of the unit, through the long slot at the bottom of the access panel. The gas connection to the unit is made to the 3/4-in. FPT gas inlet port on the unit gas valve.

Table 2 – Natural Gas Supply Line Pressure Ranges

UNIT	MIN	MAX
48HC**14	5.0 in. wg (1250 Pa)	13.0 in. wg (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. 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. 16.

This service connection kit consists of a 3/4-in NPT gas adapter fitting (stainless steel), a 1/2-in electrical bulkhead connector and a 11/2-in electrical bulkhead connector, connected to an “L” bracket covering the embossed (raised) section of the unit basepan in the condenser section. See Fig. 17.

1/2” ELECTRICAL BULKHEAD

11/2” ELECTRICAL CONNECTOR

BULKHEAD

CONNECTOR

3/4” NPT GAS ADAPTER FITTING

C10905

Fig. 17 - Thru-the-Base Option, Shipping Position

1.Remove the “L” bracket assembly from the unit (see Fig. 17).

2.Cut and discard the wire tie on the gas fitting. Hand tighten the fitting if it has loosened in transit.

3.Remove connector plate assembly from the “L” bracket and discard the “L” bracket, but retain the washer head screws and the gasket (located between the “L” bracket and the connector plate assembly

NOTE: Take care not to damage the gasket, as it is reused in the following step.

4.Place the gasket over the embossed area in the basepan, aligning the holes in the gasket to the holes in the basepan. See Fig. 18.

5.Install the connector plate assembly to the basepan using 8 of the washer head screws.

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