Carrier 48TCA04---A12 appendix Protective Devices, GAS Heating System, Compressor Protection

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48TC

Controller’s Power LED is Off

1.Make sure the circuit supplying power to the control- ler is operational. If not, make sure JP2 and JP3 are set correctly on the controller before applying power.

2.Verify that power is applied to the controller’s supply input terminals. If power is not present, replace or re- pair wiring as required.

Remote Test/Reset Station’s Trouble LED Does Not flash When Performing a Dirty Test, But the Control- ler’s Trouble LED Does

1.Verify that the remote test/station is wired as shown in Fig. 24. Repair or replace loose or missing wiring.

2.Configure the sensor dirty test to activate the control- ler’s supervision relay. See “Changing sensor dirty test operation.”

Sensor’s Trouble LED is On, But the Controller’s Trouble LED is OFF

Remove JP1 on the controller.

PROTECTIVE DEVICES

Compressor Protection

Overcurrent

The compressor has internal linebreak motor protection.

Overtemperature

The compressor has an internal protector to protect it against excessively high discharge gas temperatures.

High Pressure Switch

The system is provided with a high pressure switch mounted on the discharge line. The switch is stem-mounted and brazed into the discharge tube. Trip setting is 630 psig +/- 10 psig (4344 +/- 69 kPa) when hot. Reset is automatic at 505 psig (3482 kPa).

Low Pressure Switch

The system is protected against a loss of charge and low evaporator coil loading condition by a low pressure switch located on the suction line near the compressor. The switch is stem-mounted. Trip setting is 54 psig +/- 5 psig (372 +/- 34 kPa). Reset is automatic at 117 +/- 5 psig (807 +/- 34 kPa).

Evaporator Freeze Protection

The system is protected against evaporator coil frosting and low temperature conditions by a temperature switch mounted on the evaporator coil hairpin. Trip setting is 30_F +/- 5_F (-1_C +/- 3_C). Reset is automatic at 45_F (7_C).

Supply (Indoor) Fan Motor Protection

Disconnect and lockout power when servicing fan motor.

The standard supply fan motor is equipped with internal overcurrent and overtemperature protection. Protection devices reset automatically.

The High Static option supply fan motor is equipped with

apilot-circuit Thermix combination overtemperature/ overcurrent protection device. This device resets automatically. Do not bypass this switch to correct trouble. Determine the cause and correct it.

Condenser Fan Motor Protection

The condenser fan motor is internally protected against overtemperature.

Relief Device

A soft solder joint at the suction service access port provides pressure relief under abnormal temperature and pressure conditions (i.e., fire in building). Protect this joint during brazing operations near this joint.

Control Circuit, 24-V

The control circuit is protected against overcurrent conditions by a circuit breaker mounted on control transformer TRAN. Reset is manual.

GAS HEATING SYSTEM

General

The heat exchanger system consists of a gas valve feeding multiple inshot burners off a manifold. The burners fire into matching primary tubes. The primary tubes discharge into combustion plenum where gas flow converges into secondary tubes. The secondary tubes exit into the induced draft fan wheel inlet. The induced fan wheel discharges into a flue passage and flue gases exit out a flue hood on the side of the unit. The induced draft fan motor includes a Hall Effect sensor circuit that confirms adequate wheel speed via the Integrated Gas Control (IGC) board. Safety switches include a Rollout Switch (at the top of the burner compartment) and a limit switch (mounted through the fan deck, over the tubes). (See Fig. 27 and Fig. 28.)

INDUCED-

ROLLOUT

DRAFT

SWITCH

MOTOR

 

MOUNTING

 

PLATE

 

BURNER

 

SECTION

FLUE

 

EXHAUST

 

VESTIBULE

INDUCED-

PLATE

DRAFT

BLOWER

MOTOR

 

HOUSING

MANIFOLD

GAS

PRESSURE

TAP

VALVE

C06152

Fig. 27 - Burner Section Details

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Contents Table of Contents Safety ConsiderationsGeneral Unit Arrangement and AccessRoutine Maintenance What to do if you smell gasSeasonal Maintenance Supply FAN Blower Section Supply Fan Belt-DriveCooling Condenser Coil Maintenance and Cleaning RecommendationCondenser Coil Remove Surface Loaded Fibers Periodic Clean Water RinseRoutine Cleaning of Coil Surfaces One-Row CoilEvaporator Coil Refrigerant System Pressure Access PortsCleaning the Evaporator Coil Evaporator Coil Metering DevicesRefrigerant Charge To Use Cooling Charging ChartsPuronr R-410A Refrigerant No ChargeCooling Charging Charts Size Designation Nominal Tons ReferenceCooling Charging Charts C08229 C08437 C08438 C08439 Cooling Service Analysis Problem Cause RemedyConvenience Outlets Condenser-Fan AdjustmentTroubleshooting Cooling System CompressorController Smoke DetectorsSystem Unit Connect Primary TransformerSensor Smoke Detector LocationsCompleting Installation of Return Air Smoke Sensor Fiop Smoke Detector Wiring and ResponseController Alarm Test Sensor Alarm TestSensor Alarm Test Procedure Sensor and Controller TestsDirty Sensor Test Procedure Controller Alarm Test ProcedureDirty Controller Test Procedure To Configure the Dirty Sensor Test OperationDetector Cleaning Troubleshooting Compressor Protection Protective DevicesGAS Heating System Relief DeviceNatural Gas Manifold Pressure Ranges Fuel Types and PressuresNatural Gas Supply Line Pressure Ranges Liquid Propane Supply Line Pressure RangesFlue Gas Passageways Combustion-Air BlowerBurners and Igniters Cleaning and AdjustmentCheck Unit Operation and Make Necessary Adjust- ments Main BurnersLimit Switch Burner IgnitionLED Error Code Description Orifice ReplacementLED Indication Error Code Description Red LED-Status IGC Connections Orifice SizesCont. Altitude Compensation* A08-A12 Altitude Compensation* A04-A07LP Orifice Minimum heating entering air temperature Troubleshooting Heating SystemAltitude Compensation* A04-A06 Low NOx Units Heating Service Analysis Problem Cause RemedyIGC Board LED Alarm Codes IGCPremierlinkt Control PremierLink ControllerPremierLink Wiring Schematic 55 Space Temperature Sensor Wiring Space Sensor Mode PremierLink Sensor UsageThermostat Mode 56 Internal ConnectionsLctb 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 RTU-MP Controller Inputs and Outputs OutputsSpace Temperature SPT Sensors RTU-MP T-55 Sensor ConnectionsIAQ Sensor SEN J4-2 COM J4-3 24 VAC Power Exhaust output Connecting Discrete InputsCommunication Wiring Protocols RTU-MP Troubleshooting LEDs LEDs on the RTU-MP show the status of certain functionsTroubleshooting Alarms Alarms BACnet MS/TPRTU-MP Driver Manufacture Date Basic Protocol TroubleshootingModbus Code Name MeaningEconomizer Systems EconoMi$er IV Component LocationsEconoMi$er IV Wiring EconoMi$er EconoMi$er IV Input/Output LogicEconoMi$er IV Control Modes Supply Air Temperature SAT SensorOutdoor Air Lockout Sensor Outdoor Dry Bulb ChangeoverReturn Air Temperature or Enthalpy Sensor Mounting Location Outdoor Enthalpy ChangeoverIndoor Air Quality IAQ Sensor Input Exhaust Setpoint AdjustmentMinimum Position Control Occupancy Control Damper MovementThermostats Demand Control Ventilation DCVEconoMi$er IV Preparation CO2 Sensor ConfigurationEconoMi$er IV Sensor Usage Differential EnthalpyWiring Diagrams 48TC Typical Unit Wiring Diagram Power A06, 208/230-3-60 48TC Unit Wiring Diagram Control A06 PRE-START-UP START-UP, GeneralHeating CoolingMain Burners Ventilation Continuous FanSTART-UP, RTU-MP Control Field Service TestSTART-UP, Premierlink Controls Perform System Check-OutConfiguration Space Sensor Type InputsInput Input 1 FunctionHeating, Units Without Economizer Operating SequencesBase Unit Controls Cooling, Units Without Economizer Cooling, Unit With EconoMi$erHeating With EconoMi$er PremierLink Control48TC Available Cooling Stages OAT ≤ SPT 48TC 48TC Linkage Modes Loadshed Command Gas and Electric Heat UnitsRTU-MP Sequence of Operation SchedulingBACnet Schedule Always Occupied Default OccupancyLocal Schedule BAS On/OffEconomizer Power ExhaustIndoor Air Quality Demand Limit Fastener Torque ValuesTorque Values Serial Number Format Appendix I. Model Number SignificanceModel Number Nomenclature Position NumberAppendix II. Physical Data Physical Data Cooling TonsPhysical Data Cooling 48TC*A08 48TC*A09 48TC*A12Physical Data Heating LOW Appendix III. FAN Performance General Fan Performance NotesTon Vertical Supply Ton Horizontal SupplyCFM RPM BHP Medium Static Option High Static Option 48TC**05 Phase Ton Horizontal Supply 48TC**051506 48TC**05 Phase Ton Vertical Supply1493 148648TC**06 148248TC**06 Phase Ton Horizontal Supply 48TC**06 Phase Ton Vertical SupplyPhase Ton Horizontal Supply 48TC**071103 1143 11071124 1122 11621116 4971099 1093 11331247 5791263 1273Pulley Adjustment Unit MOTOR/DRIVE Motor Pulley Turns Open ComboRange RLA LRA Appendix IV. Electrical DataIFM TypeAppendix IV. Electrical Data FLARLA LRA IFM RangeEFF at FullFAN Motor Exhaust Combustion PowerNOM IFM No P.E Type DISC. SizeUnbalanced 3-Phase Supply Voltage NOMAppendix V. Wiring Diagram List Wiring DiagramsAppendix VI. Motormaster Sensor Locations 48TC*A04 Outdoor Circuiting48TC*A09/12 Outdoor Circuiting Catalog No 48TC---2SMUnit START-UP Checklist Preliminary Information

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.
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