Carrier 50KC04-06 Service And Maintenance Instructions

52PRE-START-UPProceed as follows to inspect and prepare the unit for initialstart-up:1. Remove all access panels.2. Read and follow instructions on all WARNING, CAU-TION, and INFORMATION labels attached to, or shippedwith, unit.3. Make the following inspections:a. Inspect for shipping and handling damages such asbroken lines, loose parts, or disconnected wires, etc.b. Inspect for oil at all refrigerant tubing connectionsand on unit base. Detecting oil generally indicates arefrigerant leak. Leak-test all refrigerant tubing con-nections using electronic leak detector, halide torch,or liquid-soap solution.c. Inspect all field-wiring and factory-wiring connec-tions. Be sure that connections are completed andtight. Be sure that wires are not in contact with refrig-erant tubing or sharp edges.d. Inspect coil fins. If damaged during shipping and han-dling, carefully straighten fins with a fin comb.4. Verify the following conditions:a. Make sure that condenser-fan blade are correctly posi-tioned in fan orifice. See Condenser-Fan Adjustmentsection on page 17 for more details.b. Make sure that air filter(s) are in place.c. Make sure that condensate drain trap is filled withwater to ensure proper drainage.d. Make sure that all tools and miscellaneous loose partshave been removed.START-UP, GENERALUnit PreparationMake sure that unit has been installed in accordance with in-stallation instructions and applicable codes.Return-Air FiltersMake sure correct filters are installed in unit (see “APPENDIXB — Physical Data” on page 57). Do not operate unit withoutreturn-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 be cer-tain compressor is rotating in the proper direction. To determinewhether or not compressor is rotating in the proper direction: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.Reset thermostat at a position above room temperature. Com-pressor will shut off. Evaporator fan will shut off after a30 second delay.TO SHUT OFF UNITSet system selector switch at OFF position. Resetting thermo-stat at a position above room temperature shuts unit off tempo-rarily until space temperature exceeds thermostat setting.HeatingTo start unit, turn on main power supply.WARNINGPERSONAL INJURY HAZARDFailure to follow this warning could result in personal injuryor death.1. Follow recognized safety practices and wear protec-tive goggles when checking or servicing refrigerantsystem.2. Do not operate compressor or provide any electricpower to unit unless compressor terminal cover is inplace and secured.3. Do not remove compressor terminal cover until allelectrical sources are disconnected.4. Relieve all pressure from system before touching ordisturbing anything inside terminal box if refrigerantleak is suspected around compressor terminals.5. Never attempt to repair soldered connection whilerefrigerant system is under pressure.6. Do not use torch to remove any component. Systemcontains oil and refrigerant under pressure.To remove a component, wear protective goggles andproceed as follows:a. Shut off electrical power to unit.b. Recover refrigerant to relieve all pressure fromsystem using both high-pressure and low pressureports.c. Cut component connection tubing with tubingcutter and remove component from unit.d. Carefully unsweat remaining tubing stubs whennecessary. Oil can ignite when exposed to torchflame.