Carrier 38AU appendix Pre-Start-Up, System Check, Preliminary Checks

Page 23

PRE-START-UP

IMPORTANT: Before beginning Pre-Start-Up or Start-Up, review Start-Up Checklist at the back of this book. The Checklist assures proper start-up of a unit and provides a record of unit condition, application requirements, system information, and operation at initial start-up.

!CAUTION

UNIT DAMAGE HAZARD

Failure to follow this caution may result in equipment damage.

Do not attempt to start the condensing unit, even momentarily, until the following steps have been completed. Compressor damage may result.

System Check

1.The electrical power source must agree with the unit’s nameplate rating.

2.Check all air handler(s) and other equipment auxiliary components. Consult the manufacturer’s instructions re- garding any other equipment connected to the condens- ing unit. If the unit has field-installed accessories, be sure all are properly installed and correctly wired. If used, the airflow switch must be properly installed.

3.Check tightness of all electrical connections.

4.Be sure liquid line and low side of the system are properly leak checked and dehydrated.

5.Be sure the unit is properly charged. See “Preliminary Charge”, below.

6.Open the liquid line and suction line service valves.

7.The crankcase heater must be firmly attached to the compressor crankcase. Be sure the crankcase is warm (heater must be on for 24 hours before starting com- pressor).

Turn On Crankcase Heater —

Turn on the crankcase heater for 24 hours before starting the unit to be sure all the refrigerant is out of the oil. To energize the crankcase heater, proceed as follows:

1.Set the space thermostat set point above the space temperature so there is no demand for cooling.

2.Close the field disconnect.

Preliminary Charge —

Before starting the unit, charge liquid refrigerant into the high side of the system through the liquid service valve. The amount of refrigerant added must be at least 80% of the operating charge listed in the Physical Data table (Tables 1A through 2B, pages 6 through 9). Allow high and low side pressures to equalize before starting compressor. If pressures do not equalize readily, charge vapor on low side of system to assure charge in the evaporator. Refer to GTAC II, Module 5, Charging, Recover, Recycling, and Reclamation for liquid charging procedures.

!CAUTION

UNIT DAMAGE HAZARD

Failure to follow this caution may result in equipment damage.

Prior to starting compressor, a preliminary charge of refrigerant must be added to avoid possible compressor damage.

START-UP

38AU Units: The compressor crankcase heater must be on for 24 hours before start-up. After the heater has been on for 24 hours, the unit can be started. If no time elapsed since the preliminary charge step was completed, it is unnecessary to wait the 24-hour period.

Preliminary Checks

1.Check that electric power supply agrees with unit nameplate data.

2.Verify that the compressor crankcase heater is se- curely in place.

3.Check that the compressor crankcase heater has been on at least 24 hours.

4.Recheck for leaks using the procedure outlined in the Pre-Start-Up section, Leak Test and Dehydration. If any leaks are detected, repair as required. Evacuate and dehydrate as described in the Leak Test and De- hydration section.

5.Ensure that the preliminary charge has been added as described in the Pre-Start-Up section, Preliminary Charge.

6.All internal wiring connections must be tight, and all barriers and covers must be in place.

NOTE: The 38AU units are factory charged with the required amount of oil. If recharging in required, use Emkarate RL 32-3MAF for the 38AU units.

Compressor Rotation —

On 3-phase units with scroll compressors, it is important to be certain that the compressor is rotating in the proper direction. 38AU units are equipped with a Comfort Alert Diagnostic Module (CADM). Alert Code 7 indicates reverse power phasing.

To correct phase order:

1.Turn off power to the unit, tag disconnect.

2.Reverse any two of the unit power leads.

3.Reapply power to the compressor, verify correct pres- sures.

To verify the compressor is rotating in the proper direction:

1.Connect service gages to the suction and liquid pres- sure fittings.

2.Energize the compressor.

3.The suction pressure should drop and the liquid pres- sure should rise, as is normal on any start-up.

38AU

23

Page 22 Page 24
Image 23
Page 22 Page 24
Contents Contents Installation, Start---Up Service InstructionsReplacement/Retrofit R-22 to PuronR Safety ConsiderationsInstallation Guideline Unit Damage Hazard InstallationRtpf UnitMchx 38AUD*25 38AUZ*25Condenser Fans Unit Size 38AURefrigerant TYPE‡ CompressorScroll Pressurestat Settings kPa High CutoutNominal Capacity kW Rtpf Shipping Charge kgFace Area sq ft total Rows/Fins per inch FPI Rtpf Shipping Charge A/B lbOil Charge A/B oz Qty...r/s Motor Hp Nema Diameter mm Operating Weight kg Novation Coil Al TubeRtpf Shipping Charge A/B kg Oil Charge A/B LU Z a 2 5 a 0 G 6 a 0 a 0 a Do not Bury Refrigeration Lines InstallationMatching 38AU Model To Evaporator Coil Jobsite SurveyCheck 38AU Model with Evaporator Coil Connections Provide Safety ReliefSlab Mount Equivalent Lengths for Common Fittings ft38AUZ 16-25 Piping Recommendations Single-Circuit Unit Liquid LiftSuction Riser Hot Gas Bypass 38AUD 16-25 Piping Recommendations Two-Circuit UnitVertical Separation outdoor unit above indoor unit Insulate Suction LinesRefrigerant Specialties Part Numbers Install Filter Driers and Moisture IndicatorsMake Piping Connections Install Liquid Line Solenoid ValveCapacity Control Liquid Line Solenoid Valve Selecting an AccumulatorPreliminary Charge Evacuation/DehydrationAll Units Field Power SupplyUnits with Factory-Installed Disconnect Fire HazardElectrical Operation Hazard Convenience OutletsConvenience Outlet Utilization Notice Label Field Control WiringThermostat Control Transformer WiringUnbalanced 3-Phase Supply Voltage Unit Wire/Fuse or Hacr Breaker Sizing DataPreliminary Checks PRE-START-UPSTART-UP System CheckStart Unit Advanced Scroll Temperature Protection AstpAdjust Refrigerant Charge Using plotted operating pointFinal Checks 38AUZ*25 Check Compressor Oil Level38AUD*16 Charging Chart Novation 38AUZ*16 Charging Chart Rtpf 38AUD*16 Charging Chart Rtpf 38AUD*25 Charging Chart Rtpf Typical 38AUZ Wiring Diagram 15 Ton 230V Tandem Unit Shown Typical 38AUD Wiring Diagram 15 Ton 230V Dual Unit Shown Base Unit Controls Operating SequenceEquipment Damage Hazard Routine System MaintenanceService Refrigeration SystemLiquid Line Filter Drier Field Refrigerant Access PortsFactory High-Flow Access Ports Input Terminal Voltage Comfort Alert Diagnostic ModuleLockout LED Status CodesCompressor Protection 38AUD Size 16 Cabinet LPS 38AUZ,D Size 25 Cabinet 38AUZ*25 Compressor Assembly Rear View NOVATIONt Type Novation Coil Cleaning and MaintenanceRepairing Novation Condenser Tube Leaks Coil Type IdentificationUnit Reliability Hazard Routine Cleaning of Round-Tube Plate Fin Rtpf CoilsReplacing NOVATIONt Condenser Coil Fastener Torque Values TroubleshootingProblem Solution Compressor does not RUN Compressor Stops on HIGH-PRESSURE SwitchSystem is Noisy Problem Solution Compressor Cycles on LOW-PRESSURE SwitchCompressor Running but Cooling Insufficient Unit Operates TOO Long or ContinuouslyAppendix B Wiring Diagram ListAppendix a Operation Low Ambient Option Factory InstalledTroubleshooting Appendix C38AUZ*16 & 38AUD*16 Novation 38AUZ*16/25 & 38AUD*16/25 Rtpf Motormaster Sensor LocationDimensions --- MM Unit Baffle Wind Baffle DimensionDimensions --- Inches Unit Baffle Wind Baffles Fabrication 15 Ton Wind Baffle Brackets Fabrication Front Front Back Left Right Catalog No 38AU---09SI II. PRE-START-UP Outdoor Unit START-UP ChecklistCheck Voltage Imbalance
Top Page Image Contents