Carrier 48VT(N) Install Duct Connections, Configuring Units for Downflow Vertical Discharge

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Fig. 7 - Sediment Trap

48VT-- A

IN

TEE

OUTFIRE OR EXPLOSION HAZARD

Step 9 — Install Duct ConnectionsConfiguring Units for Downflow (Vertical) DischargeManual background NIPPLE

CAP

C99020

Fig. 7 - Sediment Trap

5.Install an accessible, external, manual main shutoff valve in gas supply pipe within 6 ft (1.8 m) of heating section.

6.Install ground-joint union close to heating section between unit manual shutoff and external manual main shut-off valve.

7.Pressure test all gas piping in accordance with local and national plumbing and gas codes before connecting piping to unit.

NOTE: Pressure test the gas supply system after the gas supply piping is connected to the gas valve. The supply piping must be disconnected from the gas valve during the testing of the piping systems when test pressure is in excess of 0.5 psig. Pressure test the gas supply piping system at pressures equal to or less than 0.5 psig. The unit heating section must be isolated from the gas piping system by closing the external main manual shutoff valve and slightly opening the ground-joint union.

!WARNING

FIRE OR EXPLOSION HAZARD

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

-Connect gas pipe to unit using a backup wrench to avoid damaging gas controls.

-Never purge a gas line into a combustion chamber. Never test for gas leaks with an open flame. Use a commercially available soap solution made specifically for the detection of leaks to check all connections.

-Use proper length of pipe to avoid stress on gas control manifold.

-If a flexible connector is required or allowed by authority having jurisdiction, black iron pipe shall be installed at furnace gas valve and extend a minimum of 2 in. (51 mm) outside furnace casing.

-If codes allow a flexible connector, always use a new connector. do not use a connector which has previously serviced another gas appliance.

8.Check for gas leaks at the field-installed and factory-installed gas lines after all piping connections have been completed. Use a commercially available soap solution

made specifically for the detection of leaks (or method specified by local codes and/or regulations).

Step 9 — Install Duct Connections

The unit has duct flanges on the supply- and return-air openings on the side and bottom of the unit. For downshot applications, the ductwork connects to the roof curb (See Fig. 2 and 3 for connection sizes and locations).

Configuring Units for Downflow (Vertical) Discharge

!WARNING

ELECTRICAL SHOCK HAZARD

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

Before installing or servicing system, always turn off main power to system. There may be more than one disconnect switch. Tag the disconnect switch with a suitable warning label.

1.Open all electrical disconnects before starting any service work.

2.Remove horizontal (metal) duct covers to access vertical (downflow) discharge duct knockouts in unit basepan. (See Fig. 8.)

3.Starting in a corner as shown in Fig. 9, score the panel in both directions from the corner. Tap the panel out from the scored corner using a small hammer. Be careful and not damage any other part of the unit.

4.If unit ductwork is to be attached to vertical opening flanges on the unit base (jackstand applications only), do so at this time.

!CAUTION

PROPERTY DAMAGE HAZARD

Failure to follow this caution may result in property damage.

Collect ALL screws that were removed. Do not leave screws on rooftop as permanent damage to the roof may occur.

5.It is recommended that the base insulation around the perimeter of the vertical return-air opening be secured to the base with aluminum tape. Applicable local codes may require aluminum tape to prevent exposed fiberglass.

6.Reinstall both horizontal duct covers. Ensure opening is air- and watertight.

7.After completing unit conversion, perform all safety checks and power up unit.

NOTE: The design and installation of the duct system must be in accordance with the standards of the NFPA for installation of nonresidence-type air conditioning and ventilating systems, NFPA 90A or residence-type, NFPA 90B; and/or local codes and

ordinances.

Adhere to the following criteria when selecting, sizing, and installing the duct system:

1.Units are shipped for horizontal duct installation (by removing duct covers).

2.Select and size ductwork, supply-air registers, and return-air grilles according to American Society of Heating, Refrigeration and Air Conditioning Engineers (ASHRAE) recommendations.

3.Use flexible transition between rigid ductwork and unit to prevent transmission of vibration. The transition may be screwed or bolted to duct flanges. Use suitable gaskets to ensure weather tight and airtight seal.

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Contents TABLE OF CONTENTS SAFETY CONSIDERATIONSFig. 1 - Unit 48VT-A Installation InstructionsRECEIVING AND INSTALLATION INTRODUCTIONStep 1 - Check Equipment Step 2 - Provide Unit SupportA09146 Fig. 2 - 48VT-A24-30Unit Dimensions48VT--A A09147 Fig. 3 - 48VT-A36-60Unit Dimensions48VT--A Fig. 4 - Roof Curb Dimensions 48VTSMALL CURB ROOF CURB DETAILACCESS PANELS MUST BE IN PLACE WHEN RIGGING Step 5 - Rig and Place UnitInspection Rigging/Lifting of Unit See FigStep 7 - Install Flue Hood Step 8 - Install Gas PipingStep 6 - Connect Condensate Drain Fig. 6 - Condensate TrapStep 9 - Install Duct Connections Configuring Units for Downflow Vertical DischargeFig. 7 - Sediment Trap FIRE OR EXPLOSION HAZARDTable 1 - Physical Data - Unit 48VT-A Fig. 8 - Supply and Return Duct Opening48VT--A Horizontal Duct CoversTable 1 - Physical Data - Unit 48VT-ACont’d Table 2 - Maximum Gas Flow CapacityTable 3 - Heating Inputs 48VT--AStep 10 - Install Electrical Connections Special Procedures for 208-VOperationHigh-VoltageConnections Control Voltage ConnectionsBalance Point Setting-Thermidistator Hybrid PRE-START-UPTransformer Protection ThermostatStep 3 - Start-upHeating and Make Adjust- ments START-UPStep 1 - Check for Refrigerant Leaks Step 2 - Unit Sequence of OperationAdjust Gas Input Fig. 11 - Burner AssemblyCheck Heating Control Check Gas InputLimit Switches Check Burner FlameNormal Operation Airflow and Temperature RiseStep 4 - Start-upCooling and Make Adjust- ments Rollout SwitchChecking and Adjusting Refrigerant Charge Indoor Airflow and Airflow AdjustmentsGas Heating Fan Speed Set-up Continuous Fan OperationTable 6 - Color Coding for Indoor Fan Motor Leads 48VT--AFig. 14 - Interface Fan Board IFB Table 8 - 48VT-AWet Coil Pressure Drop48VT--A Table 7 - Filter Pressure Drop Table IN. W.C48VT--A UNIT48VT--A Heating48VT--A 129548VT--A 144548VT--A 1448Fig. 15 - 208/230-1-60Wiring Diagram, Unit 48VT-A 48VT AA09209 Fig. 16 - 208/230-3-60Wiring Diagram, Unit 48VT-A48VT--A Fig. 17 - Cooling Charging Table-Subcooling 48VT--A50VT500173 REV A09099MAINTENANCE Cleaning the Blower Motor and WheelAir Filter Indoor Blower and MotorLimit Switch Induced Draft combustion air Blower AssemblyFig. 18 - Blower Housing and Flue Collector Box Fig. 19 - Unit Access PanelsElectrical Controls and Wiring Outdoor FanRefrigerant Circuit Fig. 20 - Removal of Motor and Blower WheelPressure Switches Loss of Charge SwitchHigh-PressureSwitch Gas InputPage HPS - High Pressure Switch LCS - Loss of Charge SwitchFig. 24 - Refrigerant Circuit AccuraterMetering De viceTROUBLESHOOTING START-UPCHECKLISTUNIT OPERATION AND SAFETY HAZARD Synthetic Roof Precautionary ProcedurePURONR R-410AQUICK REFERENCE GUIDE 48VT--ASYMPTOM 48VT--A48VT--A Table 12 - Troubleshooting Guide-HeatingTable 13 - Troubleshooting Guide-LEDStatus Codes Remove and Store in Job Files I. PRELIMINARY INFORMATION MODEL NOTEMPERATURES PRESSURES48VT--A Catalog No 48VT---05SIEdition Date 04/09 Replaces 48VT---04SI
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