Carrier 48VT(N) Outdoor Fan, Electrical Controls and Wiring, Refrigerant Circuit, 48VT--A

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Fig. 20 - Removal of Motor and Blower Wheel

BLOWER

HOUSING

2 SETSCREWS

(HIDDEN)

C99085

Fig. 20 - Removal of Motor and Blower Wheel

A07680

Fig. 21 - Burner Rack Removed

FEEDER TUBE

Fig. 21 - Burner Rack Removed STUB TUBE

Fig. 22 - Defrost Thermostat Location DEFROST

THERMOSTAT

C99029

Fig. 22 - Defrost Thermostat Location

Outdoor Fan

!CAUTION

UNIT OPERATION HAZARD

Failure to follow this caution may result in damage to unit components.

Keep the outdoor fan free from all obstructions to ensure proper cooling operation. Never place articles on top of the unit.

1.Remove 6 screws holding outdoor grille and motor to top cover.

2.Turn motor/grille assembly upside down on top cover to expose the fan blade.

3.Inspect the fan blades for cracks or bends.

4.If fan needs to be removed, loosen the setscrew and slide the fan off the motor shaft.

5.When replacing fan blade, position blade back to the same position as before.

6.Ensure that setscrew engages the flat area on the motor shaft when tightening.

7.Replace grille.

Electrical Controls and Wiring

Inspect and check the electrical controls and wiring annually. Be sure to turn off the gas supply, and then the electrical power to the unit.

Remove access panels (see Fig. 19) to locate all the electrical controls and wiring. Check all electrical connections for tightness. Tighten all screw connections. If any discolored or burned connections are noticed, disassemble the connection, clean all the parts, re-strip the wire end and reassemble the connection properly and securely.

After inspecting the electrical controls and wiring, replace the access panels (see Fig. 19). Start the unit, and observe at least one complete heating cycle and one complete cooling cycle to ensure proper operation. If discrepancies are observed in any operating cycle, or if a suspected malfunction has occurred, check each electrical component with the proper electrical instrumentation. Refer to the unit wiring label when making these checkouts.

NOTE: Refer to the heating and/or cooling sequence of operation in this publication as an aid in determining proper control operation.

Refrigerant Circuit

Annually inspect all refrigerant tubing connections and the unit base for oil accumulations. Detecting oil generally indicates a refrigerant leak.

!WARNING

EXPLOSION, PERSONAL INJURY AND ENVIRONMENTAL HAZARD

Failure to follow this warning could result in personal injury, death or property damage.

System under pressure. Relieve pressure and recover all refrigerant before system repair or final unit disposal. Use all service ports and open all flow-control devices, including solenoid valves.

If oil is detected or if low cooling performance is suspected, leak-test all refrigerant tubing using an electronic leak-detector, halide torch, or liquid-soap solution. If a refrigerant leak is detected, refer to the Check for Refrigerant Leaks section.

48VT-- A

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Contents SAFETY CONSIDERATIONS TABLE OF CONTENTSFig. 1 - Unit 48VT-A Installation InstructionsINTRODUCTION RECEIVING AND INSTALLATIONStep 1 - Check Equipment Step 2 - Provide Unit SupportA09146 Fig. 2 - 48VT-A24-30Unit Dimensions48VT--A A09147 Fig. 3 - 48VT-A36-60Unit Dimensions48VT--A 48VT Fig. 4 - Roof Curb DimensionsSMALL CURB ROOF CURB DETAILStep 5 - Rig and Place Unit ACCESS PANELS MUST BE IN PLACE WHEN RIGGINGInspection Rigging/Lifting of Unit See FigStep 8 - Install Gas Piping Step 7 - Install Flue HoodStep 6 - Connect Condensate Drain Fig. 6 - Condensate TrapConfiguring Units for Downflow Vertical Discharge Step 9 - Install Duct ConnectionsFig. 7 - Sediment Trap FIRE OR EXPLOSION HAZARDFig. 8 - Supply and Return Duct Opening Table 1 - Physical Data - Unit 48VT-A48VT--A Horizontal Duct CoversTable 2 - Maximum Gas Flow Capacity Table 1 - Physical Data - Unit 48VT-ACont’dTable 3 - Heating Inputs 48VT--ASpecial Procedures for 208-VOperation Step 10 - Install Electrical ConnectionsHigh-VoltageConnections Control Voltage ConnectionsPRE-START-UP Balance Point Setting-Thermidistator HybridTransformer Protection ThermostatSTART-UP Step 3 - Start-upHeating and Make Adjust- mentsStep 1 - Check for Refrigerant Leaks Step 2 - Unit Sequence of OperationFig. 11 - Burner Assembly Adjust Gas InputCheck Heating Control Check Gas InputCheck Burner Flame Limit SwitchesNormal Operation Airflow and Temperature RiseRollout Switch Step 4 - Start-upCooling and Make Adjust- mentsChecking and Adjusting Refrigerant Charge Indoor Airflow and Airflow AdjustmentsContinuous Fan Operation Gas Heating Fan Speed Set-upTable 6 - Color Coding for Indoor Fan Motor Leads 48VT--ATable 8 - 48VT-AWet Coil Pressure Drop Fig. 14 - Interface Fan Board IFB48VT--A Table 7 - Filter Pressure Drop Table IN. W.CUNIT 48VT--AHeating 48VT--A1295 48VT--A1445 48VT--A1448 48VT--A48VT A Fig. 15 - 208/230-1-60Wiring Diagram, Unit 48VT-AA09209 Fig. 16 - 208/230-3-60Wiring Diagram, Unit 48VT-A48VT--A 48VT--A Fig. 17 - Cooling Charging Table-Subcooling50VT500173 REV A09099Cleaning the Blower Motor and Wheel MAINTENANCEAir Filter Indoor Blower and MotorInduced Draft combustion air Blower Assembly Limit SwitchFig. 18 - Blower Housing and Flue Collector Box Fig. 19 - Unit Access PanelsOutdoor Fan Electrical Controls and WiringRefrigerant Circuit Fig. 20 - Removal of Motor and Blower WheelLoss of Charge Switch Pressure SwitchesHigh-PressureSwitch Gas InputPage LCS - Loss of Charge Switch HPS - High Pressure SwitchFig. 24 - Refrigerant Circuit AccuraterMetering De viceSTART-UPCHECKLIST TROUBLESHOOTINGUNIT OPERATION AND SAFETY HAZARD Synthetic Roof Precautionary Procedure48VT--A PURONR R-410AQUICK REFERENCE GUIDE48VT--A SYMPTOM48VT--A Table 12 - Troubleshooting Guide-HeatingTable 13 - Troubleshooting Guide-LEDStatus Codes I. PRELIMINARY INFORMATION MODEL NO Remove and Store in Job FilesTEMPERATURES PRESSURESCatalog No 48VT---05SI 48VT--AEdition Date 04/09 Replaces 48VT---04SI
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