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Installation, Start-Up and
Service Instructions
CONTENTS
Page
GENERAL ...................................2
SAFETY CONSIDERATIONS ...................2
INSTALLATION .............................2-37
Rigging and Unit Placement ..................2
Roof Curb ...................................2
Roof Mount ..................................2
Slab Mount ..................................2
Positioning ..................................3
Field-Fabricated Ductwork ....................6
Condensate Drains ..........................10
Install Outdoor Hoods .......................10
• UNIT SIZES 034 AND 044
• UNIT SIZES 054-074
Outdoor-Air Inlet Adjustments ...............10
• MANUAL OUTDOOR-AIR DAMPER
• ECONOMIZER SETTINGS
Field Wire Routing ..........................17
• UNIT SIZES 034 AND 044
• UNIT SIZES 054-074
Field Electrical Connections .................17
• POWER WIRING
• CONTROL WIRING
Gas Piping (48 Series Units Only) ............36
Installing Flue/Inlet Hoods (48 Series Units
Only) ......................................36
• UNIT SIZES 034 AND 044
• UNIT SIZES 054-074
PRE-START-UP ............................38-41
Unit Preparation ............................38
Compressor Mounting .......................38
Evaporator-Fan Shipping Brackets ...........38
• UNIT SIZES 034 AND 044
• UNIT SIZES 054-074
Internal Wiring ..............................38
Refrigerant Service Valves ...................38
Crankcase Heaters ..........................38
Compressor Oil .............................38
Gas Manifold Pressure (48 Series
Units Only) ................................39
Unit Voltage ................................39
Leak Test and Dehydration ..................39
Evaporator-Fan Belts, Pulleys, and Sheaves ..39
Condenser Fans and Motors .................40
Return-Air Filters ...........................40
Economizer Inlet Screens ...................40
Economizer Dampers .......................40
25% Outdoor-Air Damper ....................40
Initial Check ................................41
START-UP .................................41,42
General .....................................41
Operating Sequences .......................41
• COOLING, UNITS WITHOUT ECONOMIZER
• HEATING, UNITS WITHOUT ECONOMIZER
Page
• COOLING, UNITS WITH ECONOMIZER
• HEATING, UNITS WITH ECONOMIZER
• VENTILATION AIR CIRCULATION (Continuous Fan)
• AUTOMATIC CHANGEOVER USING AUTOMATIC
CHANGEOVER THERMOSTAT
Head Pressure Control ......................42
SERVICE ..................................42-53
Service Access .............................42
• COMPRESSORS
• LIQUID SERVICE VALVES, FILTER DRIERS, AND
SIGHT GLASSES
• EVAPORATOR-FAN MOTORS, PULLEYS, AND
BELTS
• POWER EXHAUST MOTORS, PULLEYS, AND
BELTS
• UNIT CONTROL BOX
• GAS HEAT SECTION (48 Series Units Only)
• MAIN AND PILOT BURNERS (48 Series Units Only)
• FLUE GAS PASSAGEWAYS (48 Series Units Only)
• COMBUSTION AIR BLOWER (48 Series Units Only)
• ECONOMIZER DAMPER MOTOR
• ELECTRIC HEATER CONTROL BOX (50 Series
Units Only)
• HEATER BOX (50 Series Units Only)
• 25% OUTDOOR-AIR DAMPER
• MODULATING POWER EXHAUST DAMPER
MOTOR
• RETURN-AIR FILTERS
• CONDENSER FANS AND FAN MOTORS
• INLET GUIDE VANE MOTOR
Cleaning ....................................45
Lubrication .................................45
• COMPRESSORS
• FAN SHAFT BEARINGS
• INLET GUIDE VANE BEARINGS (Units With
Optional Inlet Guide Vanes)
• FAN MOTOR BEARINGS
• DOOR HINGES
Adjustments ................................46
• EVAPORATOR FAN AND POWER EXHAUST
MOTOR PLATE
• MODULATING POWER EXHAUST DIFFERENTIAL
PRESSURE SWITCH
• INLET GUIDE VANE DIFFERENTIAL PRESSURE
SWITCH (Units With Optional Inlet Guide Vanes and
Static Pressure Control)
• BELT INSTALLATION AND TENSIONING
• PULLEY ALIGNMENT
• INSTALLING ALTERNATE MOTOR PULLEY
(Evaporator Fan Only)
• CONDENSER FAN ADJUSTMENT
• 25% OUTDOOR-AIR DAMPER
• REFRIGERANT CHARGE
• PILOT LIGHT OFF (48 Series Units Only)
48DJ,DK,NP034-074
50DJ,DK,DW,DY,NB,NP034-074
Single Package Heating and Cooling Units
Manufacturer reserves the right to discontinue, or change at any time, specifications or designs without notice and without incurring obligations.
Book 1 1
Tab 1a 1b
PC 111 Catalog No. 564-818 Printed in U.S.A. Form 48/50D,N-9SI Pg 1 3-96 Replaces: 48DJ,DK-3SI;
48/50NB,NP-1SI; 50DJ,DK-9SI