Carrier 48VT(N) Introduction, Receiving And Installation, Check Equipment, Provide Unit Support

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48VT-- A

48VT-- A

signal words: DANGER, WARNING, and CAUTION. These words are used with the safety-alert symbol. DANGER identifies the most serious hazards which will result in severe personal injury or death. WARNING signifies hazards which could result in per- sonal injury or death. CAUTION is used to identify unsafe practic- es which may result in minor personal injury or product and prop- erty damage. NOTE is used to highlight suggestions which will result in enhanced installation, reliability, or operation.

!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. Turn off accessory heater power switch if applicable. TAG THE DISCONNECT SWITCH WITH A SUITABLE WARNING LABEL.

!WARNING

FIRE, EXPLOSION, ELECTRICAL SHOCK AND CARBON MONOXIDE POISONING HAZARD

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

A qualified installer or agency must use only factory-authorized kits or accessories when modifying this product.

!CAUTION

CUT HAZARD

Failure to follow this caution may result in personal injury.

When removing access panels (see Fig. 19) or performing maintenance functions inside your unit, be aware of sharp sheet metal parts and screws. Although special care is taken to reduce sharp edges to a minimum, be extremely careful when handling parts or reaching into the unit.

INTRODUCTION

The 48VT-A unit (see Fig. 1) is a fully self-contained, combination Category I gas heating/electric heating and cooling unit designed for outdoor installation (See Fig. 2 and 3 for unit dimensions). All unit sizes have return and discharge openings for both horizontal and downflow configurations, and are factory shipped with all downflow duct openings covered. Units may be installed either on a rooftop, a cement slab, or directly on the ground, if local codes permit (See Fig. 4 for roof curb dimensions).

Models with an N in the fifth position of the model number are dedicated Low NOx units designed for California installations. These models meet the California maximum oxides of nitrogen (NOx) emissions requirements of 40 nanograms/joule or less as shipped from the factory and must be installed in California Air Quality Management Districts or any other regions in North America where a Low NOx rule exists.

RECEIVING AND INSTALLATION

Step 1 — Check Equipment

IDENTIFY UNIT

The unit model number and serial number are stamped on the unit information plate. Check this information against shipping papers.

INSPECT SHIPMENT

Inspect for shipping damage before removing packaging materials. If unit appears to be damaged or is torn loose from its anchorage, have it examined by transportation inspectors before removal. Forward claim papers directly to transportation company. Manufacturer is not responsible for any damage incurred in transit. Check all items against shipping list. Immediately notify the nearest equipment distribution office if any item is missing. To prevent loss or damage, leave all parts in original packages until installation.

Step 2 — Provide Unit Support

For hurricane tie downs, contact distributor for details and PE (Professional Engineering) Certificate if required.

ROOF CURB

Install accessory roof curb in accordance with instructions shipped with curb (See Fig. 4). Install insulation, cant strips, roofing, and flashing. Ductwork must be attached to curb.

IMPORTANT: The gasketing of the unit to the roof curb is critical for a water tight seal. Install gasketing material supplied with the roof curb. Improperly applied gasketing also can result in air leaks and poor unit performance.

Curb should be level to within 1/4 in. (6 mm). This is necessary for unit drain to function properly. Refer to accessory roof curb installation instructions for additional information as required.

SLAB MOUNT

Place the unit on a solid, level concrete pad that is a minimum of 4 in. (102 mm) thick with 2 in. (51 mm) above grade. The slab should be flush on the compressor end of the unit (to allow condensate drain installation) and should extend 2 in. (51 mm) on the three remaining sides of the unit. Do not secure the unit to the slab except when required by local codes.

Step 3 — Field Fabricate Ductwork

Secure all ducts to roof curb and building structure on vertical discharge units. Do not connect ductwork to unit. For horizontal applications, unit is provided with flanges on the horizontal openings. All ductwork should be secured to the flanges. Insulate and weatherproof all external ductwork, joints, and roof openings with counter flashing and mastic in accordance with applicable codes.

Ducts passing through an unconditioned space must be insulated and covered with a vapor barrier.

If a plenum return is used on a vertical unit, the return should be ducted through the roof deck to comply with applicable fire codes.

Read unit rating plate for any required clearances around ductwork. Cabinet return-air static shall not exceed -.25 IN. W.C.

Step 4 — Provide Clearances

The required minimum operating and service clearances are shown in Fig. 2 and 3.

IMPORTANT: Do not restrict outdoor airflow. An air restriction at either the outdoor-air inlet or the fan discharge may be detrimental to compressor life.

The condenser fan pulls air through the condenser coil and discharges it through the top grille. Be sure that the fan discharge does not recirculate to the condenser coil. Do not locate the unit in either a corner or under an overhead obstruction. The minimum clearance under a partial overhang (such as a normal house overhang) is 48-in. (1219 mm) above the unit top. The maximum horizontal extension of a partial overhang must not exceed 48-in. (1219 mm).

Do not place the unit where water, ice, or snow from an overhang or roof will damage or flood the unit. Do not install the unit on carpeting or other combustible materials. The unit may be installed on wood flooring or on Class A, B, or C roof covering materials.

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Contents Fig. 1 - Unit 48VT-A TABLE OF CONTENTSSAFETY CONSIDERATIONS Installation InstructionsStep 1 - Check Equipment RECEIVING AND INSTALLATIONINTRODUCTION Step 2 - Provide Unit SupportA09146 Fig. 2 - 48VT-A24-30Unit Dimensions48VT--A A09147 Fig. 3 - 48VT-A36-60Unit Dimensions48VT--A SMALL CURB Fig. 4 - Roof Curb Dimensions48VT ROOF CURB DETAILInspection ACCESS PANELS MUST BE IN PLACE WHEN RIGGINGStep 5 - Rig and Place Unit Rigging/Lifting of Unit See FigStep 6 - Connect Condensate Drain Step 7 - Install Flue HoodStep 8 - Install Gas Piping Fig. 6 - Condensate TrapFig. 7 - Sediment Trap Step 9 - Install Duct ConnectionsConfiguring Units for Downflow Vertical Discharge FIRE OR EXPLOSION HAZARD48VT--A Table 1 - Physical Data - Unit 48VT-AFig. 8 - Supply and Return Duct Opening Horizontal Duct CoversTable 3 - Heating Inputs Table 1 - Physical Data - Unit 48VT-ACont’dTable 2 - Maximum Gas Flow Capacity 48VT--AHigh-VoltageConnections Step 10 - Install Electrical ConnectionsSpecial Procedures for 208-VOperation Control Voltage ConnectionsTransformer Protection Balance Point Setting-Thermidistator HybridPRE-START-UP ThermostatStep 1 - Check for Refrigerant Leaks Step 3 - Start-upHeating and Make Adjust- mentsSTART-UP Step 2 - Unit Sequence of OperationCheck Heating Control Adjust Gas InputFig. 11 - Burner Assembly Check Gas InputNormal Operation Limit SwitchesCheck Burner Flame Airflow and Temperature RiseChecking and Adjusting Refrigerant Charge Step 4 - Start-upCooling and Make Adjust- mentsRollout Switch Indoor Airflow and Airflow AdjustmentsTable 6 - Color Coding for Indoor Fan Motor Leads Gas Heating Fan Speed Set-upContinuous Fan Operation 48VT--A48VT--A Fig. 14 - Interface Fan Board IFBTable 8 - 48VT-AWet Coil Pressure Drop 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 50VT500173 REV Fig. 17 - Cooling Charging Table-Subcooling48VT--A A09099Air Filter MAINTENANCECleaning the Blower Motor and Wheel Indoor Blower and MotorFig. 18 - Blower Housing and Flue Collector Box Limit SwitchInduced Draft combustion air Blower Assembly Fig. 19 - Unit Access PanelsRefrigerant Circuit Electrical Controls and WiringOutdoor Fan Fig. 20 - Removal of Motor and Blower WheelHigh-PressureSwitch Pressure SwitchesLoss of Charge Switch Gas InputPage Fig. 24 - Refrigerant Circuit HPS - High Pressure SwitchLCS - Loss of Charge Switch AccuraterMetering De viceUNIT OPERATION AND SAFETY HAZARD TROUBLESHOOTINGSTART-UPCHECKLIST Synthetic Roof Precautionary ProcedurePURONR R-410AQUICK REFERENCE GUIDE 48VT--ASYMPTOM 48VT--A48VT--A Table 12 - Troubleshooting Guide-HeatingTable 13 - Troubleshooting Guide-LEDStatus Codes TEMPERATURES Remove and Store in Job FilesI. PRELIMINARY INFORMATION MODEL NO PRESSURESEdition Date 04/09 48VT--ACatalog No 48VT---05SI Replaces 48VT---04SI
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