Carrier 48EZ(N)-A Install Duct Connections, Configuring Units for Downflow Vertical Discharge

Step 9 — Install Duct Connections

The unit has duct flanges on the supply- and return-air openings on the side and bottom of the unit. For downshot applications, the ductwork connects to the roof curb (See Fig. 2 and 3 for connection sizes and locations).

Configuring Units for Downflow (Vertical) Discharge

!WARNING

ELECTRICAL SHOCK HAZARD

Failure to follow this warning could result in personal injury or death.

Before installing or servicing system, always turn off main power to system and install lockout tag. There may be more than one disconnect switch.

1.Open all electrical disconnects before starting any service work.

2.Remove horizontal (metal) duct covers to access vertical (downflow) discharge duct knockouts in unit basepan. (See Fig. 8.)

!CAUTION

PROPERTY DAMAGE HAZARD

Failure to follow this caution may result in property damage.

Collect ALL screws that were removed. Do not leave screws on rooftop as permanent damage to the roof may occur.

To remove downflow return and supply knockout covers, break front and right side connecting tabs with a screwdriver and hammer. Push cover down to break rear and left side tabs.

3.	Use flexible transition between rigid ductwork and unit to
	prevent transmission of vibration. The transition may be
	screwed or bolted to duct flanges. Use suitable gaskets to
	ensure weather tight and airtight seal.
4.	All units must have field-supplied filters or accessory filter
	rack installed in the return-air side of the unit.
	Recommended sizes for filters are shown in Table 1.
5.	Size all ductwork for maximum required airflow (either
	heating or cooling) for unit being installed. Avoid abrupt
	duct size increases or decreases or performance may be
	affected.
6.	Adequately insulate and weatherproof all ductwork located
	outdoors. Insulate ducts passing through unconditioned
	space, and use vapor barrier in accordance with latest issue
	of Sheet Metal and Air Conditioning Contractors National
	Association (SMACNA) and Air Conditioning Contractors
	of America (ACCA) minimum installation standards for
	heating and air conditioning systems. Secure all ducts to
	building structure.
7.	Flash, weatherproof, and vibration-isolate all openings in	A
	building structure in accordance with local codes and good	--
		48EZ
	building practices.

NOTE: These panels are held in place with tabs similar to an electrical knockout. Reinstall horizontal duct covers (Fig. 8) shipped on unit from factory. Insure openings are air and watertight.

NOTE: The design and installation of the duct system must be in accordance with the standards of the NFPA for installation of nonresidence-type air conditioning and ventilating systems, NFPA 90A or residence-type, NFPA 90B; and/or local codes and ordinances.

Horizontal Duct Covers

Basepan Downflow (Vertical) Supply Knockout

A09061

Basepan Downflow (Vertical) Return Knockout

Adhere to the following criteria when selecting, sizing, and installing the duct system:

1.Units are shipped for horizontal duct installation (by removing duct covers).

2.Select and size ductwork, supply-air registers, and return-air grilles according to American Society of Heating, Refrigeration and Air Conditioning Engineers (ASHRAE) recommendations.

A09060

Fig. 8 - Supply and Return Duct Opening

9