Carrier 58PHA/PHX Installation, Combination of Indoor and Outdoor Air, Bottom Return Air Inlet

of at least 2 in.2/1,000 Btuh (4,400 mm2/kW) of total input rating of all gas appliances.

2.An attic or crawlspace may be considered a space that freely communicates with the outdoors provided there are

adequate permanent ventilation openings directly to outdoors having free area of at least 1-in.2/4,000 Btuh of total input rating forall gas appliances in the space.

3.In spaces that use the Indoor Combustion Air Method, infiltration should be adequate to provide air for combustion, permanent ventilation and dilution of flue gases. However, in buildings with unusually tight construction, additional air MUST be provided using the methods described in the Outdoor Combustion Air Method section.

Unusually tight construction is defined as construction with:

	a. Walls and ceilings exposed to the outdoors have a
	continuous, sealed vapor barrier. Openings are gasketed
58PHA
	or sealed and
	CIRCULATING AIR		VENT THROUGH ROOF
		DUCTS
			AIR
				12"	MAX (305mm)
			COMBUSTIONOFFRONT IN.3LEASTATBESHALL			IN.
				1 SQ
				PER 1000
				BTUH* IN DOOR
				OR WALL
	INTERIOR			UNCONFINED
				SPACE
	HEATED
	SPACE
				6" MIN (152mm)
			CLEARANCEIN OPENINGS	(FRONT)Ü
				1 SQ IN.
				PER 1000
				BTUH* IN DOOR
				OR WALL
						12" MAX (305mm)
	CIRCULATING AIR DUCTS

*Minimum opening size is 100 in.2 with minimum dimensions of 3 in. (76 mm).

*Minimum of 3 in. (76 mm), when type ---B1 vent is used.

A03175

Fig. 8 - Air for Combustion, Ventilation, and Dilution from

Indoors

b.Doors and openable windows are weatherstripped and

c.Other openings are caulked or sealed. These include joints around window and door frames, between sole plates and floors, between wall-ceiling joints, between wall panels, at penetrations for plumbing, electrical and gas lines, etc.

Combination of Indoor and Outdoor Air

1.Indoor openings shall comply with the Indoor Combustion Air Method below and,

2.Outdoor openings shall be located as required in the Outdoor Combustion Air Method menioned previously and,

3.Outdoor openings shall be sized as follows:

a.Calculate the Ratio of all Indoor Space volume divided by required volume for Indoor Combustion Air Method below.

A02098

Fig. 9 - Removing Bottom Closure Panel

b. Outdoor opening size reduction Factor is 1 minus the Ratio in a. above.

c. Minimum size of Outdoor openings shall be the size required in Outdoor Combustion Air Method above multiplied by reduction Factor in b. above. The minimum dimension of air openings shall be not less than 3 in. (80 mm).

INSTALLATION

UPFLOW INSTALLATION

Bottom Return Air Inlet

These furnaces are shipped with bottom closure panel installed in bottom return-air opening. Remove and discard this panel when bottom return air is used. To remove bottom closure panel, perform the following:

1.Tilt or raise furnace and remove two screws holding bottom filler panel. (See Fig. 9.)

2.Rotate bottom filler panel downward to release holding tabs.

3.Remove bottom closure panel.

4.Reinstall bottom filler panel and screws.

Side Return Air Inlet

These furnaces are shipped with bottom closure panel installed in bottom return-air opening. This panel MUST be in place when only side return air is used.

NOTE: Side return-air openings can be used in UPFLOW and most HORIZONTAL configurations. Do not use side return-air openings in DOWNFLOW configuration.

Leveling Legs (If Desired)

In upflow position with side return inlet(s), leveling legs may be used. (See Fig. 10.) Install field-supplied, 5/16 x 1-1/2 in. (8 x

38mm) (max) corrosion-resistant machine bolts, washers and nuts.

NOTE: Bottom closure must be used when leveling legs are used. It may be necessary to remove and reinstall bottom closure panel to install leveling legs. To remove bottom closure panel, see Item 1. in Bottom Return Air Inlet section.

To install leveling legs:

1.Position furnace on its back. Locate and drill a hole in each bottom corner of furnace. (See Fig. 10.)

2.For each leg, install nut on bolt and then install bolt and nut in hole. (Install flat washer if desired.)

3.Install another nut on other side of furnace base. (Install flat washer if desired.)

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