Carrier 48TCA04---A12 Always Occupied Default Occupancy, Local Schedule, BACnet Schedule, Cooling

Page 79

control to the occupied heating or cooling setpoints. Scheduling functions are located under occupancy determination and the schedule menu accessed by the Menu softkey (see Appendix - for menu structure). Your local time and date should be set for these functions to operate properly. Five scheduling functions are available by changing the Occupancy Source to one of the following selections:

Always Occupied (Default Occupancy)

The unit will run continuously. RTU-MP ships from the factory with this setting.

Local Schedule

The unit will operate according to the schedule configured and stored in the unit. The local schedule is made up of three hierarchy levels that consist of two Override schedules, twelve Holiday and four Daily schedules, and are only accessible by the BACview screen (handheld or virtual).

The Daily schedule is the lowest schedule in the hierarchy and is overridden by both the Holiday and Override schedule. It consists of a start time, a stop time (both in 24 hour mode) and the seven days of the week, starting with Monday and ending in Sunday. To select a daily schedule scroll to the Schedules menu off of the Menu selection. Enter the User password and change the Occupancy Source to Local Schedule. Scroll down and over to the Daily menu and press enter. Choose one of the four Daily schedules by pressing the Next softkey and change the Use? point from NO to YES by selecting the point and pressing the INCR or DECR softkey. Press the OK softkey and scroll to the start and stop times. Edit these times following the same steps as the Use? point. Finally scroll down to the Days: section and highlight the days required for the Daily schedule by INCR or DECR softkeys and press OK softkey.

The Holiday schedule is created to override the Daily schedule and identify a specific day and month of the year to start and stop the unit and change control to the unoccupied heating and cooling setpoints. Follow the same steps to turn on one of the twelve Holiday schedules and start and stop times. Next, select one out of the twelve months and one out of the thirty-one days of that month. The RTU-MP will now ignore the Daily schedule for the specific day and time you selected and follow the Holiday Schedule for this period.

The Override schedules primary purpose is to provide a temporary change in the occupied heating and cooling setpoints and force the unit to control to the unoccupied heating and cooling setpoints. This would occur on a set day in a particular month and last during the start and stop time configured. The Override schedule is enabled by following the same steps to create the Holiday schedule.

NOTE: Push button override is only available when running a local or BACnet Schedule.

BACnet Schedule

For use with a Building Automation System that supports native BACnet scheduling is scheduling the unit. With the Occupancy Source set to BACnet schedule the BAS will control the unit through network communication and it’s own scheduling function.

BAS On/Off

The Building Automation System is scheduling the unit via an On/Off command to the BAS ON/OFF software point. The Building Automation System can be speaking BACnet, Modbus, or N2 and is writing to the BAS On/Off point in the open protocol point map.

NOTE: If the BAS supports NATIVE BACnet scheduling, then set the Occupancy Source to BACnet schedule. If the BAS is BACnet but does NOT support NATIVE BACnet scheduling, then set the Occupancy Source to BAS On/Off.

DI On/Off

Ahard-wired input on the RTU-MP will command the unit to start/stop. Inputs 3, 5, 8, and 9 on plug J5 can be hard-wired to command the unit to start/stop.

NOTE: Scheduling can either be controlled via the unit or the BAS, but NOT both.

Indoor Fan

The indoor fan will be turned on whenever any one of the following conditions is true:

SIt is in the occupied mode. This will be determined by its own internal occupancy schedule.

SWhenever there is a demand for cooling or heating in the unoccupied mode.

S Whenever the remote occupancy switch is closed during DI On/Off schedule type or if occupancy is forced occupied by the BAS during BAS On/Off schedule type.

When transitioning from unoccupied to occupied, there will be a configured time delay of 5 to 600 seconds before starting the fan. The fan will continue to run as long as compressors, heating stages, or the dehumidification relays are on when transitioning from occupied to unoccupied with the exception of Shutdown mode. If Fire Shutdown, safety chain, SAT alarm or SPT alarm are active; the fan will be shutdown immediately regardless of the occupancy state or demand.

The RTU-MP has an optional Supply Fan Status input to provide proof of airflow. If this is enabled, the point will look for a contact closure whenever the Supply Fan Relay is on. If it is not enabled then it will always be the same state as the Supply Fan Relay. The cooling, economizer, heating, dehumidification, CO2 and power exhaust routines will use this input point for fan status.

Cooling

The compressor outputs are controlled by the Cooling Control PID Loop and Cooling Stages Capacity algorithm. They will be used to calculate the desired number of stages needed to satisfy the space by comparing the Space Temperature (SPT) to the Occupied Cool Setpoint plus the T56 slider offset when occupied and the Unoccupied Cool Setpoint (UCSP) plus the T56 slider offset, if unoccupied. The economizer, if available, will be used for cooling in addition to the compressors. The following conditions must be true in order for this algorithm to run:

S Indoor Fan has been ON for at least 30 seconds.

S Heat mode is not active and the time guard between modes equals zero.

S If occupied and the SPT >(occupied cool setpoint plus

48TC

79

Page 78 Page 80
Image 79
Page 78 Page 80
Contents Safety Considerations Table of ContentsWhat to do if you smell gas Unit Arrangement and AccessRoutine Maintenance GeneralSeasonal Maintenance Supply Fan Belt-Drive Supply FAN Blower SectionCooling Condenser Coil Maintenance and Cleaning RecommendationCondenser Coil One-Row Coil Periodic Clean Water RinseRoutine Cleaning of Coil Surfaces Remove Surface Loaded FibersEvaporator Coil Metering Devices Refrigerant System Pressure Access PortsCleaning the Evaporator Coil Evaporator CoilNo Charge To Use Cooling Charging ChartsPuronr R-410A Refrigerant Refrigerant ChargeSize Designation Nominal Tons Reference Cooling Charging ChartsCooling Charging Charts C08229 C08437 C08438 C08439 Problem Cause Remedy Cooling Service AnalysisCompressor Condenser-Fan AdjustmentTroubleshooting Cooling System Convenience OutletsUnit Connect Primary Transformer Smoke DetectorsSystem ControllerSmoke Detector Locations SensorFiop Smoke Detector Wiring and Response Completing Installation of Return Air Smoke SensorSensor and Controller Tests Sensor Alarm TestSensor Alarm Test Procedure Controller Alarm TestTo Configure the Dirty Sensor Test Operation Controller Alarm Test ProcedureDirty Controller Test Procedure Dirty Sensor Test ProcedureDetector Cleaning Troubleshooting Relief Device Protective DevicesGAS Heating System Compressor ProtectionLiquid Propane Supply Line Pressure Ranges Fuel Types and PressuresNatural Gas Supply Line Pressure Ranges Natural Gas Manifold Pressure RangesCombustion-Air Blower Flue Gas PassagewaysMain Burners Cleaning and AdjustmentCheck Unit Operation and Make Necessary Adjust- ments Burners and IgnitersBurner Ignition Limit SwitchLED Error Code Description Orifice ReplacementLED Indication Error Code Description Red LED-Status Orifice Sizes IGC ConnectionsCont. Altitude Compensation* A08-A12 Altitude Compensation* A04-A07LP Orifice Minimum heating entering air temperature Troubleshooting Heating SystemAltitude Compensation* A04-A06 Low NOx Units Problem Cause Remedy Heating Service AnalysisIGC IGC Board LED Alarm CodesPremierLink Controller Premierlinkt ControlPremierLink Wiring Schematic 55 Space Temperature Sensor Wiring PremierLink Sensor Usage Space Sensor Mode56 Internal Connections Thermostat ModeLctb Indoor CO2 Sensor 33ZCSENCO2 Connections PremierLink Filter Switch Connection Recommended Cables RTU-MP Control SystemColor Code Recommendations RTU-MP Multi-Protocol Control Board RTU-MP System Control Wiring Diagram Outputs RTU-MP Controller Inputs and OutputsRTU-MP T-55 Sensor Connections Space Temperature SPT SensorsIAQ Sensor SEN J4-2 COM J4-3 24 VAC Power Exhaust output Connecting Discrete InputsCommunication Wiring Protocols RTU-MP Troubleshooting LEDs on the RTU-MP show the status of certain functions LEDsTroubleshooting Alarms BACnet MS/TP AlarmsRTU-MP Driver Code Name Meaning Basic Protocol TroubleshootingModbus Manufacture DateEconoMi$er IV Component Locations Economizer SystemsEconoMi$er IV Wiring EconoMi$er IV Input/Output Logic EconoMi$erOutdoor Dry Bulb Changeover Supply Air Temperature SAT SensorOutdoor Air Lockout Sensor EconoMi$er IV Control ModesOutdoor Enthalpy Changeover Return Air Temperature or Enthalpy Sensor Mounting LocationIndoor Air Quality IAQ Sensor Input Exhaust Setpoint AdjustmentMinimum Position Control Demand Control Ventilation DCV Damper MovementThermostats Occupancy ControlDifferential Enthalpy CO2 Sensor ConfigurationEconoMi$er IV Sensor Usage EconoMi$er IV PreparationWiring Diagrams 48TC Typical Unit Wiring Diagram Power A06, 208/230-3-60 48TC Unit Wiring Diagram Control A06 START-UP, General PRE-START-UPVentilation Continuous Fan CoolingMain Burners HeatingPerform System Check-Out Field Service TestSTART-UP, Premierlink Controls START-UP, RTU-MP ControlConfiguration Input 1 Function InputsInput Space Sensor TypeCooling, Unit With EconoMi$er Operating SequencesBase Unit Controls Cooling, Units Without Economizer Heating, Units Without EconomizerPremierLink Control Heating With EconoMi$er48TC Available Cooling Stages OAT ≤ SPT 48TC 48TC Scheduling Loadshed Command Gas and Electric Heat UnitsRTU-MP Sequence of Operation Linkage ModesBAS On/Off Always Occupied Default OccupancyLocal Schedule BACnet ScheduleEconomizer Power ExhaustIndoor Air Quality Demand Limit Fastener Torque ValuesTorque Values Position Number Appendix I. Model Number SignificanceModel Number Nomenclature Serial Number FormatPhysical Data Cooling Tons Appendix II. Physical Data48TC*A08 48TC*A09 48TC*A12 Physical Data CoolingPhysical Data Heating LOW General Fan Performance Notes Appendix III. FAN PerformanceTon Vertical Supply Ton Horizontal SupplyCFM RPM BHP Medium Static Option High Static Option 48TC**05 48TC**05 Phase Ton Horizontal Supply1486 48TC**05 Phase Ton Vertical Supply1493 15061482 48TC**0648TC**06 Phase Ton Vertical Supply 48TC**06 Phase Ton Horizontal Supply48TC**07 Phase Ton Horizontal Supply1122 1162 11071124 1103 11431093 1133 4971099 11161273 5791263 1247Unit MOTOR/DRIVE Motor Pulley Turns Open Combo Pulley AdjustmentType Appendix IV. Electrical DataIFM Range RLA LRAFLA Appendix IV. Electrical DataFull IFM RangeEFF at RLA LRAType DISC. Size Combustion PowerNOM IFM No P.E FAN Motor ExhaustNOM Unbalanced 3-Phase Supply VoltageWiring Diagrams Appendix V. Wiring Diagram List48TC*A04 Outdoor Circuiting Appendix VI. Motormaster Sensor LocationsCatalog No 48TC---2SM 48TC*A09/12 Outdoor CircuitingPreliminary Information Unit START-UP Checklist

48TCA04---A12 specifications

The Carrier 48TCA04---A12 is a high-efficiency rooftop air conditioning unit designed for commercial and industrial applications. Known for its reliability and performance, this model features advanced technologies that cater to diverse climate control needs.

One of the standout features of the Carrier 48TCA04---A12 is its excellent energy efficiency, which adheres to the stringent standards set by the U.S. Environmental Protection Agency. The unit utilizes a highly efficient scroll compressor combined with state-of-the-art heat exchanger technology, allowing it to operate with minimal energy consumption while providing powerful cooling capabilities.

The unit comes equipped with a robust and durable design, built to withstand various environmental conditions. Its weather-resistant cabinet is constructed from high-quality materials, ensuring long-lasting performance even in harsh climates. Additionally, the unit features a galvanized steel structure with a powder-coated finish, further enhancing its resistance to corrosion and wear.

In terms of technologies, the Carrier 48TCA04---A12 incorporates advanced controls that promote optimal performance. The unit supports Carrier's smart connectivity options, facilitating remote monitoring and adjustments via smart devices. This feature ensures convenient energy management and allows maintenance teams to access performance data, leading to proactive service interventions.

Another important characteristic of this unit is its quiet operation. The design includes sound-reducing insulation and a well-engineered airflow system, minimizing noise levels to create a more comfortable indoor environment. This is particularly important for commercial spaces such as offices and retail environments, where a tranquil atmosphere is critical for customer satisfaction and productivity.

The Carrier 48TCA04---A12 also offers diverse application flexibility, making it suitable for various locations, from small retail stores to large warehouses. With several tonnage options available, users can select a model that perfectly aligns with their specific cooling needs. Additionally, the unit can be easily integrated with existing HVAC systems, providing a seamless solution for upgrading or retrofitting older installations.

To sum up, the Carrier 48TCA04---A12 rooftop air conditioning unit stands out due to its exceptional energy efficiency, durable construction, advanced technology, and quiet operation, making it a reliable choice for commercial and industrial cooling solutions. Its flexibility and smart technology integrations ensure that it meets a wide range of climate control requirements effectively.
Top Page Image Contents