Carrier NP034-074 - Page 69

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Fig. 73 — Typical Power Wiring Schematic; 48/50NP,50NB Units (054-074, 208/230 and 460 v Shown)

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Table of Contents1
General2
Safety Considerations2
Installation2
Rigging and Unit Placement2
Roof Curb2
Roof Mount2
Slab Mount2
Positioning3
Field-Fabricated Ductwork6
Condensate Drains10
Install Outdoor Hoods10
- Unit Sizes10
Outdoor-Air Inlet Adjustments10
- Manual Outdoor-Air Damper10
- Economizer Settings10
Field Wire Routing17
- Unit Sizes17
Field Electrical Connections17
- Power Wiring17
- Control Wiring34
Gas Piping (48 Series Units Only)36
Installing Flue/Inlet Hoods36
- Only)37
- Unit Sizes38
Pre-Start-Up38
Unit Preparation38
Compressor Mounting38
Evaporator-Fan Shipping Brackets38
Internal Wiring38
Refrigerant Service Valves38
Crankcase Heaters38
Compressor Oil38
- Units Only)39
Unit Voltage39
Leak Test and Dehydration39
Evaporator-Fan Belts, Pulleys, and Sheaves39
Condenser Fans and Motors40
Return-Air Filters40
Economizer Inlet Screens40
Economizer Dampers40
25% Outdoor-Air Damper40
Initial Check41
Start-Up41
General41
Operating Sequences41
- Cooling, Units Without Economizer41
- Heating, Units Without Economizer41
- VENTILATION AIR CIRCULATION (Continuous Fan)42
- Automatic Changeover Using Automatic42
Head Pressure Control42
Service42
Service Access42
- Compressors42
- Liquid Service Valves, Filter Driers, and Sight Glasses43
- Evaporator-Fan Motors, Pulleys, and Belts43
- Power Exhaust Motors, Pulleys, and Belts43
- Unit Control Box43
- GAS HEAT SECTION (48 Series Units Only)43
- MAIN and PILOT BURNERS (48 Series Units Only)43
- FLUE GAS PASSAGEWAYS (48 Series Units Only)43
- COMBUSTION AIR BLOWER (48 Series Units Only)43
- Unit Sizes 034 and44
- ELECTRIC HEATER CONTROL BOX (50 Series Units Only)44
- Modulating Power Exhaust Damper Motor45
- Inlet Guide Vane Motor45
Cleaning45
Lubrication45
- Inlet Guide Vane Bearings45
Adjustments46
- Evaporator Fan and Power Exhaust Motor Plate46
- Modulating Power Exhaust Differential46
- Inlet Guide Vane Differential Pressure46
- Switch46
- Belt Installation and Tensioning46
- Installing Alternate Motor Pulley46
- Condenser Fan Adjustment46
- AUTOMATIC PILOT ADJUSTMENT (48 Series Units Only)49
- GAS VALVE ADJUSTMENT (48 Series Units Only)50
- Main Burner Adjustment50
Main Burner Removal (48 Series Units Only)50
Switch Adjustment50
Refrigerant Feed Components50
Thermostatic Expansion Valve (TXV)50
Moisture/Liquid Indicator51
Filter Drier51
Liquid Line Service Valve51
Compressor Discharge Service Valve51
Compressor Suction Service Valve51
Protective Devices51
- Compressor Protection51
- Evaporator-Fan Motor Protection51
- Condenser-Fan Motor Protection51
Relief Devices51
Control Circuit, 115 V52
Control Circuit, 24 V52
Electric Heat (50 Series Units Only)52
Gas Heat (48 Series Units Only)52
Troubleshooting52
Economizer52
- Economizer Motor Checkout52
- Economizer Control Board Checkout52
Unit Control Board Checkout53
- Basic Check53
- Detailed Check53
Start-Up Checklist72

Carrier NP034-074 - Page 69

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