Carrier 48EZ-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.)

3.Using Fig. 9 as a guide, proceed to cut out the downflow duct panels.

4.Drill 1/2 in. (13 mm) diameter or larger holes in all four corners of duct panels.

NOTE: On large chassis units remove sheet metal shields on panels by using a screw driver to shear off retainers and discard.

5.On left and side supply duct opening side with keyhole or single bladed hacksaw cut out panel along “V” groove.

6.On right side, with keyhole or single blade hacksaw, with teeth facing up and starting from the front and moving to the rear, cut along “V” groove.

7.Now with three sides cut, flex panel up and down to re- move.

8.Replace side access panel and duct cover.

9.After completing unit conversion, perform all safety checks and power up unit.

Alternate Method

1.Open all electrical disconnects and install lockout tag before starting any service work.

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

3.Leave top shipping crate on unit during this method.

4.Tip unit over on the front side (access panels) so the bottom of the base pan is accessible.

5.Drill two holes diagonally opposed, of suitable size to ac- commodate jigsaw or reciprocating saw. (See Fig. 9.)

NOTE: On large chassis units remove sheet metal shields on panels by using a screw driver to shear off retainers and discard.

!CAUTION

UNIT COMPONENT DAMAGE HAZARD

Failure to follow this caution may result in damage to the unit being installed.

When cutting duct panels, do not contact or damage any internal components (heat exchanger, electric heat). Do not use a saw blade that protrudes more than 1 in. (25 mm) into unit.

!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.

6.Using a suitable saw cut along “V” groove and remove duct panels.

7.Tip unit back onto its base and replace duct covers.

8.After completing unit conversion, perform all safety checks and power up unit.

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.

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.

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 building structure in accordance with local codes and good building practices.

48EZ -- A

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