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

Installation, Start-Up andService InstructionsCONTENTSPageSAFETY CONSIDERATIONS . . . . . . . . . . . . . . . . . . . 1INSTALLATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-31Step 1 — Provide Unit Support . . . . . . . . . . . . . . . 1• ROOF CURB• ALTERNATE UNIT SUPPORTStep 2 — Rig and Place Unit . . . . . . . . . . . . . . . . . . 2• POSITIONING• ROOF MOUNTStep 3 — Field Fabricate Ductwork . . . . . . . . . . . . 2Step 4 — Install Flue Hood . . . . . . . . . . . . . . . . . . 12Step 5 — Trap Condensate Drain . . . . . . . . . . . . 13Step 6 — Install Gas Piping . . . . . . . . . . . . . . . . . . 13Step 7 — Controls Options . . . . . . . . . . . . . . . . . . 13• CONSTANT VOLUME APPLICATIONS• VARIABLE AIR VOLUME (VAV) APPLICATIONSStep 8 — Make Electrical Connections . . . . . . . 16• POWER WIRING• FIELD POWER SUPPLY• FIELD CONTROL WIRINGStep 9 — Make Outdoor-Air InletAdjustments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24• ECONOMIZER• ECONOMIZER SETTINGSStep 10 — Position Power Exhaust/BarometricRelief Hood . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29Step 11 — Install All Accessories . . . . . . . . . . . . 30START-UP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31-44SERVICE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44-55TROUBLESHOOTING . . . . . . . . . . . . . . . . . . . . . . 56-61START-UP CHECKLIST . . . . . . . . . . . . . . . . CL-1,CL-2SAFETY CONSIDERATIONSInstallation and servicing of air-conditioning equipmentcan be hazardous due to system pressure and electrical com-ponents. Only trained and qualified service personnel shouldinstall, repair, or service air-conditioning equipment.Untrained personnel can perform the basic maintenancefunctions of cleaning coils and filters and replacing filters.All other operations should be performed by trained servicepersonnel. When working on air-conditioning equipment, ob-serve precautions in the literature, tags and labels attachedto the unit, and other safety precautions that may apply.Follow all safety codes. Wear safety glasses and work gloves.Use quenching cloth for unbrazing operations. Have fire ex-tinguishers available for all brazing operations.Before performing service or maintenance operations onunit, turn off main power switch to unit. Electrical shockcould cause personal injury.1. Improper installation, adjustment, alteration, serv-ice, or maintenance can cause property damage, per-sonal injury, or loss of life. Refer to the User’sInformation Manual provided with this unit for moredetails.2. Do not store or use gasoline or other flammable va-pors and liquids in the vicinity of this or any otherappliance.What to do if you smell gas:1. DO NOT try to light any appliance.2. DO NOT touch any electrical switch, or use any phonein your building.3. IMMEDIATELY call your gas supplier from a neigh-bor’s phone. Follow the gas supplier’s instructions.4. If you cannot reach your gas supplier, call the firedepartment.Disconnect gas piping from unit when pressure testingat pressure greater than 0.5 psig. Pressures greater than0.5 psig will cause gas valve damage resulting in haz-ardous condition. If gas valve is subjected to pressuregreater than 0.5 psig, it must be replaced before use. Whenpressure testing field-supplied gas piping at pressures of0.5 psig or less, a unit connected to such piping must beisolated by closing the manual gas valve(s).INSTALLATIONStep 1 — Provide Unit Support1. All panels must be in place when rigging.2. Unit is not designed for handling by fork truck.ROOF CURB — Assemble or install accessory roof curb inaccordance with instructions shipped with this accessory. SeeFig. 1 and 2. Install insulation, cant strips, roofing, and counterflashing as shown. Ductwork can be installed to roof curbbefore unit is set in place. Curb should be level. This is nec-essary to permit unit drain to function properly. Unit level-ing tolerance is shown in Fig. 1 and 2. Refer to AccessoryRoof Curb Installation Instructions for additional informa-tion as required. When accessory roof curb is used, unit maybe installed on class A, B, or C roof covering material.IMPORTANT: The gasketing of the unit to the roofcurb is critical for a watertight seal. Install gasket withthe roof curb as shown in Fig. 1 and 2. Improperlyapplied gasket can also result in air leaks and poor unitperformance.48EJ,EK,EW,EY024-048Single Package Rooftop UnitsElectric Cooling/Gas HeatingManufacturer reserves the right to discontinue, or change at any time, specifications or designs without notice and without incurring obligations.Book 1Tab 1aPC 111 Catalog No. 564-962 Printed in U.S.A. Form 48E-5SI Pg 1 8-97 Replaces: 48E-3SI