Carrier 38AU appendix Operating Sequence, Base Unit Controls

Carrier 38AU appendix Convenience Outlet Utilization Notice Label, Field Control Wiring Carrier 38AU appendix Thermostat, Control Transformer Wiring Carrier 38AU appendix Unit Wire/Fuse or Hacr Breaker Sizing Data, Unbalanced 3-Phase Supply Voltage Carrier 38AU appendix Pre-Start-Up, System Check, Preliminary Checks Carrier 38AU Start Unit, Compressor Overload, Advanced Scroll Temperature Protection Astp, Adjust Refrigerant Charge Carrier appendix 38AUZ*25 Check Compressor Oil Level, Final Checks Carrier appendix 38AUD*16 Charging Chart Novation Carrier appendix 38AUZ*16 Charging Chart Rtpf Carrier appendix 38AUD*16 Charging Chart Rtpf Carrier appendix 38AUD*25 Charging Chart Rtpf Carrier appendix Typical 38AUZ Wiring Diagram 15 Ton 230V Tandem Unit Shown Carrier appendix Typical 38AUD Wiring Diagram 15 Ton 230V Dual Unit Shown Carrier 38AU appendix Operating Sequence, Base Unit Controls Carrier 38AU appendix Routine System Maintenance, Service, Refrigeration System, Equipment Damage Hazard Carrier 38AU appendix Liquid Line Filter Drier, Field Refrigerant Access Ports, Factory High-Flow Access Ports Carrier 38AU appendix Comfort Alert Diagnostic Module, Input Terminal Voltage Carrier 38AU appendix LED Status Codes, Lockout Carrier 38AU appendix Compressor Protection Carrier appendix 38AUD Size 16 Cabinet Carrier 38AU appendix Lps Carrier appendix 38AUZ,D Size 25 Cabinet Carrier appendix 38AUZ*25 Compressor Assembly Rear View Carrier 38AU appendix Coil Type Identification, NOVATIONt Type, Round-Tube Plate-Fin Rtpf Type Carrier 38AU appendix Replacing NOVATIONt Condenser Coil, Routine Cleaning of Round-Tube Plate Fin Rtpf Coils Carrier 38AU appendix Fastener Torque Values, Troubleshooting, Problem Solution Compressor does not RUN Carrier 38AU Problem Solution Compressor Cycles on LOW-PRESSURE Switch, Compressor Running but Cooling Insufficient Carrier 38AU appendix Appendix a, Appendix B, Wiring Diagram List Carrier 38AU Appendix C, Low Ambient Option Factory Installed, Operation, Troubleshooting, Speed Control Sensor Resistance Carrier appendix Motormaster Sensor Location, 38AUZ*16 & 38AUD*16 Novation 38AUZ*16/25 & 38AUD*16/25 Rtpf Carrier 38AU appendix Wind Baffle Dimension, Dimensions --- Inches Unit Baffle, Dimensions --- MM Unit Baffle Carrier 38AU appendix Wind Baffles Fabrication Carrier 38AU appendix Ton Wind Baffle Brackets Fabrication Carrier 38AU appendix Front Carrier 38AU appendix Front Back Left Right Carrier appendix Catalog No 38AU---09SI Carrier 38AU appendix START-UP Checklist, II. PRE-START-UP Outdoor Unit
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38AU

OPERATING SEQUENCE

Base Unit Controls

Indoor (Supply) Fan —

The indoor fan contactor (IFC) is remotely located at the fan coil or fan section. If the thermostat fan operation is selected as Continuous, the IFC is energized and the indoor (supply) fan motor runs continuously. If the thermostat fan operation is selected as Automatic, the IFC will be energized on a call for Cooling; indoor (supply) fan motor runs. When thermostat call for Cooling is satisfied, the IFC is de-energized and indoor (supply) fan motor stops.

Cooling, Unit Without Economizer —

38AUZ (Single Circuit)

On a thermostat call for Cooling, IFC will be energized and indoor (supply) fan motor runs. Thermostat output Y1 is energized; terminal Y1 at 38AUZ unit receives 24-v. 24-v received at CADM1 terminal Y. If anti-recycle time delay period has not expired, CADM1 relay will remain open, de-energizing Solenoid Valve Relay (SVR) and preventing compressor start. When safety pressure switches are closed and CADM1 time delay expires, CADM1 relay closes, SVR and compressor contactor C1 are energized; liquid line solenoid valve LLSV opens, all outdoor fan motors start and Compressor 1 starts.

On a thermostat calling for Stage 2 Cooling, thermostat output Y2 is energized; terminal Y2 at 38AUZ unit receives 24-v. 24-v received at CADM2 terminal Y. If anti-recycle time delay period has not expired, CADM2 relay will remain open, preventing Compressor 2 start. When safety pressure switches are closed and CADM2 time delay expires, CADM2 relay closes, compressor contactor C2 is energized; Compressor 2 starts.

As space cooling load is satisfied, thermostat outputs Y2 and Y1 are de-energized, removing 24-v at 38AUZ terminals Y2 and Y1. Compressor 2 stops on Y2 opening. CADM2 begins its three-minute anti-recycle time delay. On Y1 opening, Compressor 1 stops, all outdoor fan motors stop and SVR relay is de-energized. Liquid line solenoid valve is de-energized and valve closes. CADM1 begins its three-minute anti-recycle time delay.

38AUD (Two Circuit)

On a thermostat call for Cooling, IFC will be energized and indoor (supply) fan motor runs. Thermostat output Y1 is energized; terminal Y1 at 38AUD unit receives 24-v. 24-v received at CADM1 terminal Y. If anti-recycle time delay period has not expired, CADM1 relay will remain open, de-energizing Solenoid Valve Relay 1 (SVR1) and preventing compressor start. When safety pressure switches are closed and CADM1 time delay expires, CADM1 relay closes, SVR1 and compressor contactor C1 are energized; liquid line solenoid valve LLSV1 opens, all outdoor fan motors start and Circuit 1 compressor starts.

On a thermostat calling for Stage 2 Cooling, thermostat output Y2 is energized; terminal Y2 at 38AUD unit receives 24-v. 24-v received at CADM2 terminal Y. If anti-recycle time delay period has not expired, CADM2 relay will remain open, de-energizing Solenoid Valve Relay 2 (SVR2) and preventing compressor start. When safety pressure switches are closed and CADM2 time delay expires, CADM2 relay closes, SVR2 and compressor contactor C2 are energized; liquid line solenoid valve LLSV2 opens and Circuit 2 compressor starts.

As space cooling load is satisfied, thermostat outputs Y2 and Y1 are de-energized, removing 24-v at 38AUD terminals Y2 and Y1. Circuit 2 compressor stops on Y2 opening; SVR2 is de-energized and LLSV2 closes. CADM2 begins its three-minute anti-recycle time delay. On Y1 opening, Circuit 1 compressor stops, all outdoor fan motors stop and SVR1 relay is de-energized. Liquid line solenoid valve LLSV1 is de-energized and valve closes. CADM1 begins its three-minute anti-recycle time delay.

All Units

If either the Low Pressure Switch or High Pressure Switch opens while thermostat output Y1 or Y2 remain energized, the compressor contactor is de-energized, the compressor stops and liquid line solenoid is de-energized (valve closes). CADM initiates a TRIP event (cooling demand sensed at CADM terminal Y but no current is measured at T1, T2, T3 motor sensors); CADM relay opens and RED LED is illuminated. TRIP condition maintains lockout of compressor operation until CADM is manually reset. Reset CADM by cycling unit main power.

Complete system shutdown may be caused by loss of main power, open compressor internal overload, open low-pressure or high-pressure switch, or a fault detected by the CADM logic. Compressor operation without cooling may indicate the compressor’s ASTP feature is active; disconnect unit power and allow compressor to cool. See Service section for further details.

Cooling, Unit With Economizer —

Refer to fan coil unit installation instructions and economizer accessory installation instructions for operating sequences when system is equipped with accessory economizer.

Heating —

Refer to fan coil unit installation instructions and accessory heating device installation instructions for operating sequences in heating mode.

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Contents Installation, Start---Up Service Instructions ContentsReplacement/Retrofit R-22 to PuronR Safety ConsiderationsInstallation Guideline Installation Unit Damage HazardRtpf UnitMchx 38AUZ*25 38AUD*25Unit Size 38AU Refrigerant TYPE‡Compressor Condenser FansPressurestat Settings kPa High Cutout Nominal Capacity kWRtpf Shipping Charge kg ScrollFace Area sq ft total Rows/Fins per inch FPI Rtpf Shipping Charge A/B lbOil Charge A/B oz Operating Weight kg Novation Coil Al Tube Rtpf Shipping Charge A/B kgOil Charge A/B L Qty...r/s Motor Hp Nema Diameter mmU Z a 2 5 a 0 G 6 a 0 a 0 a Installation Matching 38AU Model To Evaporator CoilJobsite Survey Do not Bury Refrigeration LinesProvide Safety Relief Slab MountEquivalent Lengths for Common Fittings ft Check 38AU Model with Evaporator Coil Connections38AUZ 16-25 Piping Recommendations Single-Circuit Unit Liquid LiftSuction Riser 38AUD 16-25 Piping Recommendations Two-Circuit Unit Vertical Separation outdoor unit above indoor unitInsulate Suction Lines Hot Gas BypassInstall Filter Driers and Moisture Indicators Refrigerant Specialties Part NumbersInstall Liquid Line Solenoid Valve Capacity Control Liquid Line Solenoid ValveSelecting an Accumulator Make Piping ConnectionsEvacuation/Dehydration Preliminary ChargeField Power Supply Units with Factory-Installed DisconnectFire Hazard All UnitsConvenience Outlets Electrical Operation HazardField Control Wiring Convenience Outlet Utilization Notice LabelControl Transformer Wiring ThermostatUnit Wire/Fuse or Hacr Breaker Sizing Data Unbalanced 3-Phase Supply VoltagePRE-START-UP START-UPSystem Check Preliminary ChecksAdvanced Scroll Temperature Protection Astp Adjust Refrigerant ChargeUsing plotted operating point Start Unit38AUZ*25 Check Compressor Oil Level Final Checks38AUD*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 Operating Sequence Base Unit ControlsRoutine System Maintenance ServiceRefrigeration System Equipment Damage HazardLiquid Line Filter Drier Field Refrigerant Access PortsFactory High-Flow Access Ports Comfort Alert Diagnostic Module Input Terminal VoltageLED Status Codes LockoutCompressor Protection 38AUD Size 16 Cabinet LPS 38AUZ,D Size 25 Cabinet 38AUZ*25 Compressor Assembly Rear View Novation Coil Cleaning and Maintenance Repairing Novation Condenser Tube LeaksCoil Type Identification NOVATIONt TypeUnit Reliability Hazard Routine Cleaning of Round-Tube Plate Fin Rtpf CoilsReplacing NOVATIONt Condenser Coil Troubleshooting Problem Solution Compressor does not RUNCompressor Stops on HIGH-PRESSURE Switch Fastener Torque ValuesProblem Solution Compressor Cycles on LOW-PRESSURE Switch Compressor Running but Cooling InsufficientUnit Operates TOO Long or Continuously System is NoisyAppendix B Wiring Diagram ListAppendix a Low Ambient Option Factory Installed TroubleshootingAppendix C OperationMotormaster Sensor Location 38AUZ*16 & 38AUD*16 Novation 38AUZ*16/25 & 38AUD*16/25 RtpfDimensions --- 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 START-UP Checklist II. PRE-START-UP Outdoor UnitCheck Voltage Imbalance
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