Carrier 48HC*04–14 Service And Maintenance Instructions

62! WARNINGFIRE, EXPLOSION HAZARDFailure to follow thiswarning could result indeath, serious personalinjury and/or propertydamage.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.When pressure testing field-supplied gas piping atpressures of 0.5 psig or less, a unit connected to suchpiping must be isolated by closing the manual gasvalve(s).FIRE, EXPLOSION HAZARDFailure to follow this warning could result inpersonal injury, death and/or property damage.Refer to the User’s Information Manual providedwith this unit for more details.Do not store or use gasoline or other flammablevapors and liquids in the vicinity of this or any otherappliance.What to do if you smell gas:DO NOT try to light any appliance.DO NOT touch any electrical switch, or use anyphone in your building.IMMEDIATELY call your gas supplier from aneighbor’s phone. Follow the gas supplier’sinstructions.If you cannot reach your gas supplier, call the firedepartment.! WARNINGReturn--Air FiltersEnsure correct filters are installed in unit (see Appendix II-- Physical Data). Do not operate unit without return--airfilters.Outdoor--Air Inlet ScreensOutdoor--air inlet screen must be in place before operatingunit.Compressor MountingCompressors are internally spring mounted. Do not loosenor remove compressor hold down bolts.Internal WiringCheck all electrical connections in unit control boxes.Tighten as required.Refrigerant Service PortsEach unit system has two 1/4” SAE flare (with checkvalves) service ports: one on the suction line, and one onthe compressor discharge line. Be sure that caps on theports are tight.Compressor RotationOn 3--phase units with scroll compressors, it is importantto be certain compressor is rotating in the properdirection. To determine whether or not compressor isrotating in the proper direction:1. Connect service gauges to suction and discharge pres-sure fittings.2. Energize the compressor.3. The suction pressure should drop and the dischargepressure should rise, as is normal on any start--up.If the suction pressure does not drop and the dischargepressure does not rise to normal levels:4. Note that the evaporator fan is probably also rotatingin the wrong direction.5. Turn off power to the unit and install lockout tag.6. Reverse any two of the unit power leads.7. Re--energize to the compressor. Check pressures.The suction and discharge pressure levels should nowmove to their normal start--up levels.NOTE: When the compressor is rotating in the wrongdirection, the unit will make an elevated level of noiseand will not provide cooling.CoolingSet space thermostat to OFF position. To start unit, turn onmain power supply. Set system selector switch at COOLposition and fan switch at AUTO. position. Adjustthermostat to a setting below room temperature.Compressor starts on closure of contactor.Check unit charge. Refer to Refrigerant Charge section.Reset thermostat at a position above room temperature.Compressor will shut off. Evaporator fan will shut offafter a 30--second delay.To shut off unit, set system selector switch at OFFposition. Resetting thermostat at a position above roomtemperature shuts unit off temporarily until spacetemperature exceeds thermostat setting.Main BurnersMain burners are factory set and should require noadjustment.To check ignition of main burners and heating controls,move thermostat setpoint above room temperature andverify that the burners light and evaporator fan isenergized. Check heating effect, then lower the thermostat48HC