Carrier 48TC*D08 appendix Adjustable-Pitch Pulley on Motor, Supply-Fan Pulley Adjustment Bearings

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To replace the belt:

1.Use a belt with same section type or similar size. Do not substitute a “FHP” type belt. When installing the new belt, do not use a tool (screwdriver or pry-bar) to force the belt over the pulley flanges, this will stress the belt and cause a reduction in belt life.

2.Loosen the motor mounting plate front bolts and rear bolts.

3.Push the motor and its mounting plate towards the blower housing as close as possible to reduce the cen- ter distance between fan shaft and motor shaft.

4.Remove the belt by gently lifting the old belt over one of the pulleys.

5.Install the new belt by gently sliding the belt over both pulleys and then sliding the motor and plate away from the fan housing until proper tension is achieved.

6.Check the alignment of the pulleys, adjust if neces- sary.

7.Tighten all bolts.

8.Check the tension after a few hours of runtime and re-adjust as required.

Adjustable-Pitch Pulley on Motor

The motor pulley is an adjustable-pitch type that allows a servicer to implement changes in the fan wheel speed to match as-installed ductwork systems. The pulley consists of a fixed flange side that faces the motor (secured to the motor shaft) and a movable flange side that can be rotated around the fixed flange side that increases or reduces the pitch diameter of this driver pulley. (See Fig. 6.)

As the pitch diameter is changed by adjusting the position of the movable flange, the centerline on this pulley shifts laterally (along the motor shaft). This creates a requirement for a realignment of the pulleys after any adjustment of the movable flange. Also reset the belt tension after each realignment.

Check the condition of the motor pulley for signs of wear. Glazing of the belt contact surfaces and erosion on these surfaces are signs of improper belt tension and/or belt slippage. Pulley replacement may be necessary.

To change fan speed:

1.Shut off unit power supply.

2.Loosen belt by loosening fan motor mounting nuts. (See Fig. 5.)

3.Loosen movable pulley flange setscrew. (See Fig. 6.)

4.Screw movable flange toward fixed flange to increase speed and away from fixed flange to decrease speed. Increasing fan speed increases load on motor. Do not exceed maximum speed specified.

5.Set movable flange at nearest keyway of pulley hub and tighten setscrew to torque specifications.

To align fan and motor pulleys:

1.Loosen fan pulley setscrews.

2.Slide fan pulley along fan shaft. Make angular align- ment by loosening motor from mounting.

3.Tighten fan pulley setscrews and motor mounting bolts to torque specifications.

4.Recheck belt tension.

48TC

C07075

Fig. 6 - Supply-Fan Pulley Adjustment

Bearings

This fan system uses bearings featuring concentric split locking collars. The collars are tightened through a cap screw bridging the split portion of the collar. The cap screw has a Torx T25 socket head. To tighten the locking collar: Hold the locking collar tightly against the inner race of the bearing and torque the cap screw to 65-70 in-lb (7.4-7.9 Nm). (See Fig. 7.)

C08121

Fig. 7 - Tightening Locking Collar

Motor

When replacing the motor, also replace the external-tooth lock washer (star washer) under the motor mounting base; this is part of the motor grounding system. Ensure the teeth on the lock washer are in contact with the motor’s painted base. Tighten motor mounting bolts to 120 +/- 12 in-lbs.

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Contents Safety Considerations Table of ContentsWhat to do if you smell gas Unit Arrangement and AccessGeneral Seasonal Maintenance Routine MaintenanceManual Outside Air Hood Screen Supply FAN Blower SectionSupply Fan Belt-Drive Supply-Fan Pulley Adjustment Bearings Adjustable-Pitch Pulley on MotorPeriodic Clean Water Rinse Coil Maintenance and Cleaning RecommendationCooling Condenser CoilRoutine Cleaning of Evaporator Coil Sufaces Routine Cleaning of Novation Condenser Coil SurfacesRefrigerant Charge Refrigerant System Pressure Access PortsPuronr R-410A Refrigerant Seatcore Cooling Charging Charts D08 Cooling Charging ChartsCooling Charging Charts D12 Cooling Charging Charts D14 Circuit a Cooling Charging Charts D14 Circuit B Problem Cause Remedy Cooling Service AnalysisCondenser-Fan Adjustment D14 size Condenser-Fan Adjustment D08-D12 sizeTroubleshooting Cooling System CompressorsUnit-Powered Type Non-Powered TypeConvenience Outlets Duty CycleSmoke Detectors Typical Supply Air Smoke Detector Sensor Location Smoke Detector LocationsFiop Smoke Detector Wiring and Response Completing Installation of Return Air Smoke SensorSensor Alarm Test Procedure Sensor Alarm TestController Alarm Test Sensor and Controller TestsDirty Controller Test Procedure Controller Alarm Test ProcedureDirty Sensor Test Procedure To Configure the Dirty Sensor Test OperationSD-TRK4 Remote Alarm Test Procedure Detector CleaningRemote Test/Reset Station Dirty Sensor Test Dirty Sensor Test Using an SD-TRK4Troubleshooting Compressor Protection Protective DevicesFuel Types and Pressures GAS Heating SystemControl Circuit Combustion-Air Blower Flue Gas PassagewaysMain Burners Burners and IgnitersLimit Switch Cleaning and AdjustmentCheck Unit Operation and Make Necessary Adjustments Burner Ignition LED Error Code DescriptionLED Indication Error Code Description Gas Valve Orifice ReplacementOutputs Integrated Gas Control IGC Board IGC ConnectionsAltitude Compensation Orifice SizesOrifice Carrier Drill Drill Size Part Number ElevationMinimum Heating Entering Air Temperature Troubleshooting Heating SystemHeating Service Analysis Problem Cause RemedyIGC IGC Board LED Alarm CodesReplacing Novation Condenser Coil Condenser Coil ServiceRepairing Novation Condenser Tube Leaks PREMIERLINKt Control Typical PremierLinkt System Control Wiring Diagram Temp Resistance 55 Space Temperature Sensor WiringPremierLink Sensor Usage Space Sensor ModeTB1 Terminal Field Connection Input Signal 56 Internal Connections Thermostat ModeLctb Indoor CO2 Sensor 33ZCSENCO2 Connections PremierLink Filter Switch Connection RTU-MP Control System Signal Type CCN BUS Wire CCN Plug PIN Color NumberRecommended Cables Color Code RecommendationsRTU-MP Multi-Protocol Control Board Typical RTU-MP System Control Wiring Diagram RTU-MP Controller Inputs and Outputs Configurable InputsPoint Name Type of I/O Connection PIN Name Numbers InputsRTU-MP T-55 Sensor Connections Space Temperature SPT SensorsRTU-MP / Indoor CO2 Sensor 33ZCSENCO2 Connections Communication Wiring Protocols Connecting Discrete InputsPower Exhaust output RTU-MP Troubleshooting LEDs BACview6 Handheld ConnectionsTroubleshooting Alarms BACnet MS/TP AlarmsModule Status Report Modstat Example Modbus Basic Protocol TroubleshootingManufacture Date Code Name MeaningEconoMi$er IV Component Locations ECONOMI$ER SystemsEconoMi$er IV Wiring Inputs Outputs EconoMi$erEconoMi$er IV Input/Output Logic Outdoor Air Lockout Sensor Supply Air Temperature SAT SensorEconoMi$er IV Control Modes Outdoor Dry Bulb ChangeoverOutdoor Enthalpy Changeover Differential Dry Bulb ControlMinimum Position Control Exhaust Setpoint AdjustmentIndoor Air Quality IAQ Sensor Input Demand Control Ventilation DCV Damper MovementThermostats Analog CO2 CO2 Sensor ConfigurationCO2 Sensor Standard Settings EconoMi$er IV Sensor Usage DCV Demand Controlled Ventilation and Power ExhaustEconoMi$er IV Preparation Differential EnthalpyEconoMi$er IV Troubleshooting Completion Wiring DiagramsDCV Minimum and Maximum Position Supply-Air Sensor Input48TC Typical Unit Wiring Diagram Power D08, 208/230-3-60 48TC Typical Unit Wiring Diagram Control D08, 208/230-3-60 START-UP, General PRE-START-UPUnit Preparation Gas PipingRefrigerant Service Ports Internal WiringReturn-Air Filters Outdoor-Air Inlet ScreensSTART-UP, RTU-MP Control Field Service TestVentilation Continuous Fan Perform System Check-OutConfiguration Cooling Lockout Temp Cooling/Econ SAT Low SetptHeating Heating SAT High Setpt Heating Lockout TempT55/56 Override Duration Power Exhaust SetptIAQ Low Reference @ 4mA IAQ High Reference @ 20mAOperating Sequences PremierLinkt Control Supplemental Controls48TC 48TC Number Stages Economizer Available Cooling Stages48TC 48TC Linkage Modes Rooftop Mode Value Linkage ModeAlways Occupied Default Occupancy Loadshed Command Gas and Electric Heat UnitsRTU-MP Sequence of Operation SchedulingBAS On/Off BACnet ScheduleDI On/Off Indoor FanFastener Torque Values Power ExhaustEconomizer Indoor Air QualityTorque Values Model Number Nomenclature Appendix I. Model Number SignificanceSerial Number Format Position Number Typical Designates12.5TONS Appendix II. Physical DataPhysical Data Physical Data Heating 12.5TONS Heat Anticipator Setting Amps48TC**08 48TC**12 48TC**14 Gas Connection Natural Gas Heat, Liquid Propane HeatCFM RPM BHP Appendix III. FAN Performance579 FAN PerformanceRPM BHP 48TC**14Unit MOTOR/DRIVE Motor Pulley Turns Open Combo Pulley AdjustmentElectrical Information MCA/MOCP Determination no C.O. or Unpwrd C.O Unit Combustion PowerNOM IFM FAN Motor Exhaust No P.E Type DISC. SizeSize Voltage Control Power Appendix IV. Wiring Diagram ListWiring Diagrams Catalog No 48TC-3SM Appendix V. Motormaster Sensor LocationsPreliminary Information Unit START-UP Checklist
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