Carrier 48TC Nomenclature Explained: Economizer Features and Operations
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Economizer

Economizer Exists

This point tells the controller if there is an economizer installed on the unit.

Factory Default = NO if no economizer YES if there is an economizer installed

Economizer Minimum Position

This defines the lowest economizer position when the indoor fan is running and the building is occupied.

Factory Default = 20% Range = 0-100 %

Economizer High OAT Lockout

If the outdoor air temperature rises above this value, economizer cooling will be disabled and dampers will return and stay at minimum position.

Factory Default = 75_F Range = 55-80_F

Power Exhaust Setpt

When the economizer damper position opens above this point the power exhaust operation will begin. When the damper position falls 10% below the setpoint, the power exhaust will shutdown.

Factory Default = 50% Range = 20-90 %

NOTE: This point is only used when Continuous Occ Exhaust = NO

Continuous Occ Exhaust

This point tells the controller when to run the power exhaust if equipped on the unit. If set to YES, the power exhaust will be on all the time when in occupied mode and will be off when in unoccupied mode. If set to NO the power exhaust will be controlled by the Power Exhaust Setpoint.

Factory Default = NO

IAQ

Max Differential CO2 Setpt

If the difference between indoor an outdoor air quality becomes greater then this value the damper position will stay at the IAQ Greatest Min Dmpr Pos. configuration point

Factory Default = 650 PPM Range = 300-950 PPM

IAQ Greatest Min Dmpr Pos.

This is the greatest minimum position the economizer will open to while trying to control the indoor air quality, CO2 differential.

Factory Default = 50% open Range = 10-60% open

Clockset

This submenu screen allows you to set the date and time manually. The Daylight Savings Time (DST) can also be changed here. The date and time is automatically set when ever software is downloaded. The clock is a 24 hour clock and not am/pm. The time should be verified (and maybe changed) according to unit location and time zone.

Factory Default = Eastern Standard Time

USERPW

This submenu screen allows you to change the user password to a four number password of choice. The User password change screen is only accessible with the Administrator Password (1111). The ADMIN password will always override the user password.

OPERATING SEQUENCES

Base Unit Controls

Cooling, Units Without Economizer

When thermostat calls for cooling, terminals G and Y1 are energized. The indoor-fan contactor (IFC) and compressor contactor are energized and indoor-fan motor, compressor, and outdoor fan starts. The outdoor fan motor runs continuously while unit is cooling.

Heating, Units Without Economizer

When the thermostat calls for heating, terminal W1 is energized. To prevent thermostat short-cycling, the unit is locked into the Heating mode for at least 1 minute when W1 is energized. The induced-draft motor is energized and the burner ignition sequence begins. The indoor (evaporator) fan motor (IFM) is energized 45 seconds after a flame is ignited. On units equipped for two stages of heat, when additional heat is needed, W2 is energized and the high-fire solenoid on the main gas valve (MGV) is energized. When the thermostat is satisfied and W1 is deenergized, the IFM stops after a 45-second time off delay.

Cooling, Unit With EconoMi$er IV

For Occupied mode operation of EconoMi$er IV, there must be a 24-v signal at terminals TR and N (provided through PL6-3 from the unit’s IFC coil). Removing the signal at N places the EconoMi$er IV control in Unoccupied mode.

During Occupied mode operation, indoor fan operation will be accompanied by economizer dampers moving to Minimum Position setpoint for ventilation. If indoor fan is off, dampers will close. During Unoccupied mode operation, dampers will remain closed unless a Cooling (by free cooling) or DCV demand is received.

Integrated EconoMi$er IV operation on 48TC single compressor model requires a 2-stage thermostat (Y1 and Y2 switches).

When free cooling using outside air is not available, the unit cooling sequence will be controlled directly by the space thermostat as described above as Cooling, Without Economizer. Outside air damper position will be closed or Minimum Position as determined by occupancy mode and fan signal.

When free cooling is available as determined by the appropriate changeover command (dry bulb, outdoor enthalpy, differential dry bulb or differential enthalpy), a call for cooling (Y1 closes at the thermostat) will cause the economizer control to modulate the dampers open and closed to maintain the unit supply air temperature at 50 to 55_F. Compressor will not run.

48TC

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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 SectionCondenser Coil Condenser Coil Maintenance and Cleaning RecommendationCooling 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 Indication Error Code Description Orifice ReplacementLED Error Code Description Red LED-Status Orifice Sizes IGC ConnectionsLP Orifice Altitude Compensation* A04-A07Cont. Altitude Compensation* A08-A12 Altitude Compensation* A04-A06 Low NOx Units Troubleshooting Heating SystemMinimum heating entering air temperature 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 Color Code Recommendations RTU-MP Control SystemRecommended Cables 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 Communication Wiring Protocols Connecting Discrete InputsPower Exhaust output 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$er IV Control ModesOutdoor Enthalpy Changeover Return Air Temperature or Enthalpy Sensor Mounting LocationMinimum Position Control Exhaust Setpoint AdjustmentIndoor Air Quality IAQ Sensor Input Demand Control Ventilation DCV Damper MovementThermostats Occupancy ControlDifferential Enthalpy CO2 Sensor ConfigurationEconoMi$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 ScheduleIndoor Air Quality Power ExhaustEconomizer Torque Values Fastener Torque ValuesDemand Limit 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 PerformanceCFM RPM BHP Ton Horizontal SupplyTon Vertical Supply 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

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