Carrier 48GC04 Service And Maintenance Instructions

61Return-Air FiltersEnsure correct filters are installed in unit (see Appendix B —Physical Data). Do not operate unit without return-air filters.Outdoor-Air Inlet ScreensOutdoor-air inlet screen must be in place before operating unit.Compressor MountingCompressors are internally spring mounted. Do not loosen orremove compressor hold down bolts.Internal WiringCheck all electrical connections in unit control boxes. Tightenas required.Refrigerant Service PortsEach unit system has two 1 / 4-in. SAE flare (with check valves)service ports: one on the suction line, and one on the compres-sor discharge line. Be sure that caps on the ports are tight.Compressor RotationOn 3-phase units with scroll compressors, it is important to becertain compressor is rotating in the proper direction. Todetermine whether or not compressor is rotating in the properdirection:1. Connect service gages to suction and discharge pressurefittings.2. Energize the compressor.3. The suction pressure should drop and the discharge pres-sure should rise, as is normal on any start-up.If the suction pressure does not drop and the discharge pressuredoes not rise to normal levels:1. Note that the evaporator fan is probably also rotating inthe wrong direction.2. Turn off power to the unit and install lockout tag.3. Reverse any two of the unit power leads.4. Re-energize to the compressor. Check pressures.The suction and discharge pressure levels should now move totheir normal start-up levels.NOTE: When the compressor is rotating in the wrong direction,the unit will make an elevated level of noise and will not providecooling.CoolingSet space thermostat to OFF position. To start unit, turn onmain power supply. Set system selector switch at COOL posi-tion and fan switch at AUTO. position. Adjust thermostat to asetting below room temperature. Compressor starts on closureof contactor.Check unit charge. Refer to Refrigerant Charge section onpage 15.Reset thermostat at a position above room temperature.Compressor will shut off. Evaporator fan will shut off after a30-second delay.To shut off unit, set system selector switch at OFF position.Resetting thermostat at a position above room temperatureshuts unit off temporarily until space temperature exceeds ther-mostat setting.Main BurnerMain burners are factory set and should require no adjustment.To check ignition of main burners and heating controls, movethermostat setpoint above room temperature and verify that theburners light and evaporator fan is energized. Check heatingeffect, then lower the thermostat setting below the room tem-perature and verify that the burners and evaporator fan turn off.When replacing unit orifices, order the necessary parts throughRCD. See the High Altitude Gas Conversion Kit Gas Heat-ing/Electric Cooling 3 to 15 Ton Small Rooftop Units Accesso-ry LP (Liquid Propane) Installation Instructions for detailsHeating1. Purge gas supply line of air by opening union ahead of thegas valve. If gas odor is detected, tighten union and wait 5minutes before proceeding.WARNINGIf the information in this manual is not followed exactly, afire or explosion may result causing property damage, per-sonal injury or loss of life.Do not store or use gasoline or other flammable vapors andliquids in the vicinity of this or any other appliance.WHAT TO DO IF YOU SMELL GAS• Do not try to light any appliance.• Do not touch any electrical switch; do not use anyphone in your building.• Immediately call your gas supplier from a neighbor’sphone. Follow the gas supplier’s instructions.• If you cannot reach your gas supplier, call the firedepartment.Installation and service must be performed by a qualifiedinstaller, service agency or the gas supplier.AVERTISSEMENTRISQUE D´INCENDIE OU D´EXPLOSIONSi les consignes de sécurité ne sont pas suivies à la lettre,cela peut entraîner la mort, de graves blessures ou des dom-mages matériels.Ne pas entreposer ni utiliser d´essence ni autres vapeurs ouliquides inflammables à proximité de cet appareil ou de toutautre appareil.QUE FAIRE SI UNE ODEUR DE GAZ EST DÉTECTÉE• Ne mettre en marche aucun appareil.• Ne toucher aucun interrupteur électrique; ne pasutiliser de téléphone dans le bâtiment.• Quitter le bâtiment immédiatement.• Appeler immédiatement le fournisseur de gaz enutilisant le téléphone d´un voisin. Suivre lesinstructions du fournisseur de gaz.• Si le fournisseur de gaz n´est pas accessible, appeler leservice d´incendie.L´installation et l´entretien doivent être effectués par un in-stallateur ou une entreprise d´entretien qualifié, ou le four-nisseur de gaz.CAUTIONEQUIPMENT DAMAGE HAZARDFailure to follow this caution can result in premature wearand damage to equipment.Scroll compressors can only compress refrigerant if rotat-ing in the right direction. Reverse rotation for extendedtimes can result in internal damage to the compressor.Scroll compressors are sealed units and cannot be repairedon site location.