Carrier 48HC Horizontal Duct Connection, Install Outside Air Hood Factory Option

Positioning on Curb —

Position unit on roof curb so that the following clearances are maintained: 1/4 in. (6 mm) clearance between the roof curb and the base rail inside the right and left, 1/2 in. (12 mm) clearance between the roof curb and the base rail inside the front and back. This will result in the distance between the roof curb and the base rail inside on the condenser end of the unit being approximately equal to Details A and B in Figs. 6, 7 and 8.

Do not attempt to slide unit on curb after unit is set. Doing so will result in damage to the roof curb seal.

Although unit is weatherproof, guard against water from higher level runoff and overhangs.

Flue vent discharge must have a minimum horizontal clearance of 48 in. (1220 mm) from electric and gas meters, gas regulators, and gas relief equipment. Minimum distance between unit and other electrically live parts is 48 inches (1220 mm).

Flue gas can deteriorate building materials. Orient unit such that flue gas will not affect building materials. Locate mechanical draft system flue assembly at least 48 in. (1220 mm) from an adjacent building or combustible material.

After unit is in position, remove rigging skids and shipping materials.

Step 7 — Horizontal Duct Connection

Refer to Figs. 1, 2 and 3 for locations and sizes of the horizontal duct connections. Note that there are two different return air duct connection locations – one for unit without an economizer (on back side of unit) and a different one for unit equipped with an economizer (on left end, under the economizer hood). The supply air duct connection is on the back side. See Fig. 11 for top view depicting typical horizontal duct arrangements.

Horizontal

Supply Air

					Return Air Duct		Return Air Duct
						without	with Economizer
						Economizer
										C10626
	Supply		Return without				Return with
			Economizer				Economizer
Location	Back		Back				Left end
Height --- In. (mm)	157/	(402)	493/	8		(1253)	183/		8	(467)
	8
Width --- in. (mm)	293/	(756)	233/		8	(593)	615/	8		(1564)
	4

Fig. 11 - Horizontal Duct Opening Dimensions

Field-supplied (3/4-inch) flanges should be attached to horizontal duct openings (see Fig. 11) and all ductwork should be secured to the flanges. Insulate and weatherproof all external ductwork, joints, and roof or building openings with counter flashing and mastic in accordance with applicable codes.

Step 8 — Install Outside Air Hood — Factory Option

The outside air hood for factory-option economizer and two-position damper is shipped in knock-down form and requires field assembly. The panel for the hood top is shipped on the end of the unit (see Fig. 12). The remaining parts for the hood assembly (including side panels, filters and tracks) are shipped in a carton that is secured to the rear of the blower assembly. Access the carton location through rear panel (see Fig. 13).

Hood Top	48HC
Shipping
Position

C09134

Fig. 12 - Hood Top – Shipping Position

To remove the hood parts package:

1.Remove the back blower access panel.

2.Locate and cut the strap, being careful to not damage any wiring.

3.Carefully lift the hood package carton through the back blower access opening.

See Fig. 14 for identification of the various parts of the hood assembly.

Hood

Package

C09133

Fig. 13 - Hood Package – Shipping Location

15