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Installation Instructions
CONTENTS
Page
SAFETY CONSIDERATIONS ...................1
INSTALLATION .............................1-12
Step 1 — Provide Unit Support ...............1
• ROOF CURB
• ALTERNATE UNIT SUPPORT
Step 2 — Rig and Place Unit ..................3
• POSITIONING
• ROOF MOUNT
Step 3 — Field Fabricate Ductwork ............7
Step 4 — Make Unit Duct Connections ........7
Step 5 — Install Flue Hood ...................7
Step6—TrapCondensate Drain .............8
Step 7 — Install Gas Piping ...................8
Step 8 — Make Electrical Connections ........9
• FIELD POWER SUPPLY
• FIELD CONTROL WIRING
Step 9 — Make Outdoor-Air Inlet
Adjustments ...............................10
• MANUAL OUTDOOR-AIR DAMPER
• OPTIONAL FACTORY-INSTALLED
ECONOMIZER
Step 10 — Install Outdoor-Air Hood ..........10
START-UP ................................12-17
SERVICE ..................................18-27
START-UP CHECKLIST .....................CL-1
SAFETY CONSIDERATIONS
Installation and servicing of air-conditioning equipment
can be hazardous due to system pressure and electrical com-
ponents. Only trained and qualified service personnel should
install, repair, or service air-conditioning equipment.
Untrained personnel can perform the basic maintenance
functions of cleaning coils and filters and replacing filters.
All other operations should be performed by trained service
personnel. When working on air-conditioning equipment, ob-
serve 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-
tinguishers available for all brazing operations.
Before performing service or maintenance operations on
unit, turn off main power switch to unit. Electrical shock
could cause personal injury.
1. Improper installation, adjustment, alteration, serv-
ice, or maintenance can cause property damage, per-
sonal injury, or loss of life. Refer to the User’s In-
formation Manual provided with this unit for more
details.
2. Do not store or use gasoline or other flammable va-
pors and liquids in the vicinity of this or any other
appliance.
What to do if you smell gas:
1. DO NOT try to light any appliance.
2. DO NOT touch any electrical switch, or use any phone
in your building.
3. IMMEDIATELY call your gas supplier from a neigh-
bor’s phone. Follow the gas supplier’s instructions.
4. If you cannot reach your gas supplier, call the fire
department.
Disconnect gas piping from unit when pressure testing
at pressure greater than 0.5 psig. Pressures greater than
0.5 psig will cause gas valve damage resulting in haz-
ardous condition. If gas valve is subjected to pressure
greater than 0.5 psig, itmust be replaced beforeuse. When
pressure testing field-supplied gas piping at pressures of
0.5 psig or less, a unit connected to such piping must be
isolated by closing the manual gas valve(s).
INSTALLATION
Step 1 — Provide Unit Support
ROOF CURB — Assemble or install accessory roof curb in
accordance with instructions shipped with this accessory. See
Fig. 1 and2. Install insulation, cant strips, roofing, and counter
flashing as shown. Ductwork can be installed to roof curb
before unit is set in place. Curb should be level. This is nec-
essary to permit unit drain to function properly. Unit level-
ing tolerance is ±
1
⁄
16
in. per linear ft in any direction. Refer
to Accessory Roof Curb Installation Instructions for addi-
tional information as required. When accessory roof curb is
used, unit may be installed on class A, B, or C roof covering
material.
IMPORTANT: The gasketing of the unit to the roof
curb is critical for a watertight seal. Install gasket with
the roof curb as shown in Fig. 1. Improperly applied
gasket can also result in air leaks and poor unit
performance.
Instructions continued on page 3.
48HJ015-025
Single Package Rooftop Units
Electric Cooling/Gas Heating
Manufacturer reserves the right to discontinue, or change at any time, specifications or designs without notice and without incurring obligations.
Book 1
Tab 1a
PC 111 Catalog No. 534-807 Printed in U.S.A. Form 48HJ-9SI Pg 1 2-95 Replaces: 48HJ-5SI