Carrier 48TC 04 Series

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Service and Maintenance Instructions

48TC**04 --- 16

Nominal 3 to 15 Tons

with Puron (R---410A) Refrigerant

TABLE OF CONTENTS

SAFETY CONSIDERATIONS 1....................

UNIT ARRANGEMENT AND ACCESS 3...........

ROUTINE MAINTENANCE 3.....................

SUPPLY FAN (BLOWER) SECTION 6..............

STAGED AIR VOLUME CONTROL (SAV) -- 2 SPEED

FAN WITH VARIABLE FREQUENCY

DRIVE (VFD) 7.................................

ADDITIONAL VARIABLE FREQUENCY DRIVE

(VFD) INSTALLATION AND TROUBLESHOOTING. 8

SUPPLY FAN MOTOR 8..........................

COOLING 10...................................

EVAPORATOR COIL METERING DEVICES 13......

PURONR (R--410A) REFRIGERANT 16.............

COOLING CHARGING CHARTS 21................

COMPRESSOR 34...............................

CONVENIENCE OUTLETS 36....................

SMOKE DETECTORS 37.........................

SENSOR AND CONTROLLER TESTS 41...........

INDICATORS 43................................

PROTECTIVE DEVICES 44.......................

GAS HEATING SYSTEM 45......................

PREMIERLINK CONTROL 62...................

RTU--OPEN CONTROL SYSTEM 62................

SENSORY/ACCESSORY INSTALLATION 63........

HUMIDI--MIZER ADAPTIVE DEHUMIDIFICATION

SYSTEM 64....................................

ECONOMIZER SYSTEMS 78.....................

PRE--START--UP 87..............................

START--UP, GENERAL 87........................

START--UP, PREMIERLINK CONTROLS 90.......

START--UP, RTU--OPEN CONTROLS 90............

FASTENER TORQUE VALUES 90.................

APPENDIX I. PHYSICAL DATA 91................

APPENDIX II. FAN PERFORMANCE 97............

APPENDIX III. WIRING DIAGRAMS 111...........

APPENDIX IV. MOTORMASTER SENSOR

LOCATIONS 149................................

UNIT START-UP CHECKLIST 151.................

SAFETY CONSIDERATIONS

Installation and servicing of air-conditioning equipment

can be hazardous due to system pressure and electrical

compone nts. Only trained and qualified service personnel

should install, repair, or service air-conditioning

equipment. Untrained personnel can perform the basic

maintenance functions of replacing filters. Trained service

personnel should perform all other operations.

When working on air-conditioning equipment, observe

precautions in the literature, tags and labels attached to

the unit, and other safety precautions that can apply.

Follow all safety codes. Wear safety glasses and work

gloves. Use quenching cloth for unbraz ing operations.

Have fire extinguishers available for all brazing

operations.

Follow all safety codes. Wear safety glasses and work

gloves. Use quenching cloth for brazing operations. Have

fire extinguisher available. Read these instruct ions

thoroughly and follow all warnings or cauti ons attached to

the unit. Consult local bui lding codes and National

Electrical Code (NEC) for special requirements.

Recognize safety informa tion. This is the safety--ALERT

symbol . When you see this symbol on the unit and in

instructions or ma nuals, be aware of the potential for

physical injury hazards.

Understand the signal words DANGER, WARNING,and

CAUTION. These words are used with the

safety--ALERT symbol. DANGER indicates a hazardous

situation which, if not avoided, will result in death or

severe personal inj ury. WARNING indicates a hazardous

situation which, if not avoided, could result in death or

personal injury. CAUTION indicates a hazardous

situation which, if not avoided, could result in minor to

moderate injury or product and property damage.

NOTICE is used to address practices not related to

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The device described in the manual is a 48TC series rooftop air-conditioning unit, designed for nominal capacities ranging from 3 to 15 tons, and uses Puron® (R-410A) refrigerant.

Function Description:

The 48TC unit is a packaged rooftop air-conditioning system that provides cooling, heating (gas heat), and ventilation. It can be configured for various applications, including standard efficiency, low NOx, and with specialized features like Humidi-MiZer adaptive dehumidification. The unit integrates a supply fan system, a refrigeration system with a condenser and evaporator coils, and a gas heating system. Control options include electromechanical controls, PremierLink™ Controller, and RTU-Open Multi-Protocol Controller, allowing for automated operation and integration into building automation systems (BAS).

Important Technical Specifications:

Refrigerant: Puron® (R-410A), operating at higher pressures than R-22 systems. Polyolester (POE) oil is used in the compressor.
Cooling Capacities: Available in sizes from 3 tons (04) to 15 tons (16).
Heating Capacities: Gas heating system with nominal heat inputs ranging from 60k BTUH to 350k BTUH, depending on the model and altitude. Units can be single-stage or two-stage heating.
Coil Construction: Condenser coils are available in Round Tube/Plate Fin (RTPF) (Cu/Al or Cu/Cu) or all-aluminum Novation™ Microchannel Heat Exchanger (MCHX) construction. Evaporator coils are RTPF (Cu/Al).
Metering Devices: Acutrol system for evaporator metering in most units without Humidi-MiZer. TXV (Thermostatic Expansion Valve) is used in Humidi-MiZer options, sometimes in series with Acutrol.
Fan System: Belt-drive supply fan with adjustable-pitch motor pulley for fan speed changes. Condenser fans are direct-drive.
Electrical: Available in various voltages (208-230V, 460V, 575V) and phases (1-phase or 3-phase). Convenience outlets (125-volt GFCI) can be non-powered or unit-powered.
Safety Devices: High-pressure switch (630 psig trip), low-pressure switch (54 psig trip), evaporator freeze protection (30°F trip), internal overcurrent/overtemperature protection for motors, and a soft solder joint relief device.
Smoke Detectors: Optional factory-installed smoke detectors for supply air, return air, or both, with automatic shutdown capability.
Economizer Systems: Available with EconoMi$er IV (logic control) or EconoMi$er2 (without logic control), using direct-drive damper actuators. Supports demand-controlled ventilation (DCV) with CO2 sensors.

Usage Features:

Adjustable Fan Speed: The adjustable-pitch motor pulley allows for changes in fan wheel speed to match ductwork systems, enabling optimization of airflow.
Humidi-MiZer Adaptive Dehumidification System: Provides multiple modes (Normal Cooling, Subcooling/Reheat1, Hot Gas Reheat/Reheat2) for improved dehumidification, adapting to space temperature and humidity demands.
Control System Integration: PremierLink and RTU-Open controllers allow for advanced control, configuration, and integration into building automation systems (CCN, BACnet, Modbus, Johnson N2, LonWorks).
Altitude Compensation: Gas heating systems require orifice replacement and adjustments for installations at higher elevations to maintain proper heat input rates.
Convenience Outlets: GFCI-protected 125-volt 15-A duplex receptacles for service tools, available as non-powered or unit-powered options.

Maintenance Features:

Routine Maintenance: Monthly checks recommended for air filters, outdoor hood inlet filters, belt tension/condition, pulley alignment, bearing tightness, coil cleanliness, and condensate drain.
Seasonal Maintenance: Checks at the beginning of each season for condenser fan motor/compressor mounting bolts, fan blade positioning, control box cleanliness, wiring terminal tightness, refrigerant charge, evaporator coil cleanliness, evaporator blower motor amperage, heat exchanger flue passageways, gas burner condition, gas manifold pressure, heating temperature rise, economizer inlet filters, damper travel, and gear/dampers for debris.
Filter Replacement: Return air filters are disposable fiberglass media type, accessed via a lift-out panel. Outdoor air hood inlet screens are permanent aluminum mesh-type and can be removed for cleaning.
Coil Cleaning: NOVATION condenser coils should only be cleaned with potable water, avoiding chemicals. RTPF condenser coils can be cleaned with Totaline environmentally sound coil cleaner after removing surface-loaded fibers. Evaporator coils can be cleaned with commercial coil cleaner or dishwashing detergent.
Belt Maintenance: Quarterly checks for belt condition and tension. Instructions provided for changing fan speed, aligning pulleys, and replacing the belt.
Bearing Maintenance: Bearings feature concentric split locking collars, with specific torque specifications for tightening.
Refrigerant System Service: Detailed procedures for replacing TXV, checking for leaks, evacuating, and recharging with Puron (R-410A) refrigerant. Emphasizes the use of R-410A compatible equipment and POE oil handling precautions.
Compressor Rotation Check: Procedure for verifying proper compressor rotation on 3-phase units.
Filter Drier Replacement: Required whenever the refrigerant system is exposed to the atmosphere, using factory-specified liquid-line filter driers.
Condenser Fan Adjustment: Procedure for adjusting fan height and tightening setscrews.
Gas Heating System Maintenance: Inspection of main burners, spark gap adjustment, gas valve pressure settings, and cleaning of flue gas passageways and combustion-air blower.
Smoke Detector Testing: Procedures for sensor alarm test, controller alarm test, dirty controller test, and dirty sensor test, including LED indicators for status and troubleshooting.
EconoMi$er IV Troubleshooting: Preparation procedures and checks for differential enthalpy, single enthalpy, DCV, power exhaust, and minimum/maximum damper positions.
Start-up Checklist: Comprehensive checklist for preliminary information, pre-start-up inspections, and electrical/temperature/pressure checks during start-up.