ContentsFig. 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--AA09147
Fig. 3 - 48VT-A36-60Unit Dimensions48VT--ASMALL 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--A50VT500173 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 InputPageFig. 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 CodesTEMPERATURES
Remove and Store in Job FilesI. PRELIMINARY INFORMATION MODEL NO
PRESSURESEdition Date 04/09
48VT--ACatalog No 48VT---05SI
Replaces 48VT---04SI