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

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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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Contents Safety Considerations Table of ContentsProvide Unit Support Receiving and InstallationIntroduction Check Equipment48EZ-A24-36 Unit Dimensions 48EZ-A42-60 Unit Dimensions Small Curb Hazard Rig and Place UnitProvide Clearances Personal Injury or Property DamageInspection Install Flue HoodInstall Gas Piping Connect Condensate DrainSediment Trap Fire or Explosion HazardUnit Size 48EZ Physical Data Unit 48EZ-AHeating Inputs Physical Data Unit 48EZ-A Cont’dMaximum Gas Flow Capacity Unit Component Damage Hazard Install Duct ConnectionsConfiguring Units for Downflow Vertical Discharge Alternate MethodSupply Duct Panels Control Voltage Connections Install Electrical ConnectionsSpecial Procedures for 208-V Operation High-Voltage ConnectionsFIRE, EXPLOSION, Electrical Shock Hazard Balance Point Setting-Thermidistat or Hybrid ThermostatPRE-START-UP Transformer ProtectionUnit Sequence of Operation Start-up Heating and Make Adjust- mentsSTART-UP Check for Refrigerant LeaksUnit Damage Hazard Adjust Gas InputCheck Heating Control Check Gas InputCheck Burner Flame Airflow and Temperature RiseLimit Switches Rollout SwitchChecking Cooling Control Operation Start-up Cooling and Make Adjust- mentsChecking and Adjusting Refrigerant Charge Indoor Airflow and Airflow AdjustmentsColor Coding for Indoor Fan Motor Leads Two Cooling Fan Speeds Set-up Dehumidification feature usedGas Heating Fan Speed Set-up Continuous Fan Operation48EZ-A Wet Coil Pressure Drop IN. W.C Filter Pressure Drop Table IN. W.C741 638 547 415 Heating Low Blue 1234 1168 1093 1021 961 894 825 759 687 Heating Low Blue 1736 1695 1642 1601 1553 1512 1465 1427 1381 65oF Heating 1927 1893 1858 1824 1791 1759 1720 1689 1640 65oF Heating 48EZ a 208/230-3-60 Wiring Diagram, Unit 48EZ-A Cooling Charging Table-Subcooling Indoor Blower and Motor MaintenanceCleaning the Blower Motor and Wheel Air FilterMain Burners Limit SwitchInduced Draft combustion air Blower Assembly Burner IgnitionRefrigerant Circuit Electrical Controls and WiringOutdoor Fan Indoor Airflow Pressure SwitchesLoss of Charge Switch Gas InputExplosion Hazard High-Pressure SwitchCopeland Scroll Compressor Puron Refrigerant Compressor Oil Unit Operation and Safety HazardRefrigerant System Puronr R-410A Quick Reference Guide TroubleshootingSTART-UP Checklist Symptom Cause Remedy Troubleshooting Guide Cooling or Heat Pump Heating ModeTroubleshooting Guide-LED Error Codes Troubleshooting Guide-HeatingIII. START-UP Electrical Supply Voltage Compressor Amps TemperaturesRemove and Store in Job Files Preliminary Information Model noCatalog No 48EZ---06SI
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48EZ-A specifications

The Carrier 48EZ-A and 48VT-A are two advanced rooftop unit air conditioners that exemplify innovation and efficiency in HVAC technology. Designed for commercial applications, these units provide optimal comfort while ensuring energy conservation and reliability.

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