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Installation, Start-Up and
Service Instructions
CONTENTS
Page
SAFETY CONSIDERATIONS .................1-9
General ......................................1
RECEIVING AND INSTALLATION ...........10-22
Step 1 — Check Equipment ..................10
• IDENTIFY UNIT
• INSPECT SHIPMENT
Step 2 — Provide Unit Support ..............10
• ROOF CURB
• SLAB MOUNT
• FLUSH MOUNT
Step 3 — Field Fabricate Ductwork ...........10
Step 4 — Provide Clearances ................10
Step 5 — Rig and Place Unit .................10
• UNITS WITHOUT BASE RAIL
• UNITS WITH OPTIONAL BASE RAIL
Step 6 — Connect Condensate Drain .........13
Step 7 — Install Flue Hood ..................13
Step 8 — Install Gas Piping ..................13
Step 9 — Install Duct Connections ...........16
• CONFIGURING UNITS FOR DOWNFLOW
(VERTICAL) DISCHARGE
Step 10 — Install Electrical Connections .....18
• HIGH-VOLTAGE CONNECTIONS
• SPECIAL PROCEDURES FOR 208-V
OPERATION
• CONTROL VOLTAGE CONNECTIONS;
NON-INTEGRATED CONTROL MOTOR
(NON-ICM) UNITS
• CONTROL VOLTAGE CONNECTIONS;
INTEGRATED CONTROL MOTOR (ICM)
UNITS
• HEAT ANTICIPATOR SETTING
• TRANSFORMER PROTECTION
PRE-START-UP ............................22,23
START-UP ................................23-44
MAINTENANCE ............................44-47
TROUBLESHOOTING ......................48-50
START-UP CHECKLIST .....................CL-1
NOTE TO INSTALLER — Before the installation, READ
THESE INSTRUCTIONS CAREFULLY AND COM-
PLETELY. Also, make sure the User’s Manual and Replace-
ment Guide are left with the unit after installation. The fur-
nace is NOT to be used for temporary heating of buildings
or structures under construction.
SAFETY CONSIDERATIONS
Installation and servicing of air-conditioning equipment
can be hazardous due to system pressure and electrical com-
ponents. Only trained and qualified personnel should install,
repair, or service air-conditioning equipment.
Untrained personnel can perform basic maintenance func-
tions of cleaning coils and filters. All other operations should
be performed by trained service personnel. When working
on air-conditioning equipment, observe precautions in the
literature, tags and labels attached to the unit, and other safety
precautions that may apply.
Follow all safety codes. Wear safety glasses and work gloves.
Use quenching cloth for unbrazing operations. Have fire ex-
tinguisher available for all brazing operations.
Improper installation, adjustment, alteration, service, main-
tenance, or use can cause carbon monoxide poisoning,
fire, or an explosion which can result in personal injury
or unit damage. Consult a qualified installer, service agency,
or gas supplier for information or assistance. The quali-
fied installer or agency must use only factory-authorized
kits or accessories when modifying this product.
Before performing service or maintenance operations on
unit, turn off gas supply then unit main power switch.
Electrical shock could cause personal injury.
General — The 48SS,SX units (see Fig. 1) are fully self-
contained, combination Category I gas heating/electric cool-
ing units designed for outdoor installation. See Fig. 2-9
(pages 2-9) for unit dimensions. All unit sizes have dis-
charge openings for both horizontal and downflow configu-
rations, and are factory shipped with all 4 duct openings covered.
Units may be installed either on a rooftop or a ground-level
cement slab. See Fig. 10 for roof curb dimensions.
Fig. 1 — Unit 48SX Shown With Optional Base Rail
48SS018-060
48SX024-060
Single Package Gas Heating/
Electric Cooling Units
Manufacturer reserves the right to discontinue, or change at any time, specifications or designs without notice and without incurring obligations.
Book 1 4
Tab 1a 6a
PC 111 Catalog No. 534-721 Printed in U.S.A. Form 48SS,SX-12SI Pg 1 9-98 Replaces: 48SS,SX-11SI