Carrier SINGLE PACKAGE ROOFTOP UNITS ELECTRIC COOLING/GAS HEATING 48EJ Installation And Service Instructions Manual

Also see for 48EJ: Installation, Start-Up and Service Instructions User manual

Contents

ALTERNATE UNIT SUPPORT — When the preferred curbor slab mount cannot be used, support unit with sleepers onperimeter, using unit curb support area. If sleepers cannot beused, support long sides of unit (refer to Fig. 3-6) with aminimum number of 4-in. x 4-in. pads spaced as follows:48EJ,EK,EW,EY024-034 units require 3 pads on each side;48EJ,EK,EW,EY038-048 units require 4 pads on each side.Unit may sag if supported by corners only.Step 2 — Rig and Place Unit — Inspect unit for trans-portation damage. File any claim with transportation agency.Do not drop unit; keep upright. Use spreader bars overunit to prevent sling or cable damage. Level by using unitframe as a reference; leveling tolerance is shown in Fig. 1and 2. See Fig. 7 for additional information. Unit operatingweight is shown in Table 1.NOTE: On retrofit jobs, ductwork may be attached to oldunit instead of roof curb. Be careful not to damage ductworkwhen removing old unit. Attach existing ductwork to roofcurb instead of unit.Four lifting lugs are provided on the unit base rails as shownin Fig. 7. Refer to rigging instructions on unit.POSITIONING — Maintain clearance, per Fig. 3-6, aroundand above unit to provide minimum distance from combus-tible materials, proper airflow, and service access.Do not install unit in an indoor location. Do not locateunit air inlets near exhaust vents or other sources of con-taminated air. For proper unit operation, adequate combus-tion and ventilation air must be provided in accordance withSection 5.3 (Air for Combustion and Ventilation) of theNational Fuel Gas Code, ANSI Z223.1 (American NationalStandards Institute).Although unit is weatherproof, guard against water fromhigher level runoff and overhangs.Locate mechanical draft system flue assembly at least4 ft from any opening through which combustion productscould enter the building, and at least 4 ft from any adjacentbuilding. When unit is located adjacent to public walkways,flue assembly must be at least 7 ft above grade.ROOF MOUNT — Check building codes for weight distri-bution requirements. Unit weight is shown in Table 1.Step 3 — Field Fabricate Ductwork48EJ,EK UNITS — Field-fabricated ductwork should be at-tached to the roof curb. Supply and return duct dimensionsare shown in Fig. 3 and 4. Air distribution is shown inFig. 8.To attach ductwork to roof curb, insert duct approxi-mately 10 to 11 in. up into roof curb. Connect ductwork to14-gage roof curb material with sheet metal screws drivenfrom inside the duct.Secure all ducts to the building structure, using flexibleduct connectors between roof curb and ducts as required. Ductspassing through an unoccupied space must be insulated andcovered with a vapor barrier. Outlet grilles must not liedirectly below unit discharge. The return duct must have a90-degree elbow before opening into the building space ifthe unit is equipped with power exhaust.For vertical supply and return units, tools or parts coulddrop into ductwork and cause an injury. Install 90 de-gree elbow turns in the supply and return ductwork be-tween the unit and the conditioned space. If a 90 degreeelbow cannot be installed, then grilles of sufficient strengthand density should be installed to prevent objects fromfalling into the conditioned space.48EW,EY UNITS — Remove shipping covers from supplyand return air openings. Attach field-supplied ductwork tounit. Use a single duct over both return openings and a singleduct over both supply openings. See Fig. 5 and 6 for ductopening dimensions. Secure all ducts to the building struc-ture. See Fig. 9. Use flexible duct connectors between unitand ducts as required. Insulate and weatherproof all externalductwork, joints, and building openings with counter flash-ing and mastic in accordance with applicable codes.Ducts passing through an unconditioned space must beinsulated and covered with a vapor barrier.Install accesssory barometric relief or power exhaust inthe field-fabricated return ductwork. Refer to Position PowerExhaust/Barometric Relief Damper Hood section onpage 26 for more information.Instructions continued on page 12.2