Carrier 48AJ - Manual

Manufacturer reserves the right to discontinue, or change at any time, specifications or designs without notice and without incurring obligations.
PC 111 Catalog No. 534-739 Printed in U.S.A. Form 48A,E-1SI Pg 1 107 11-01 Replaces: 48E-6SI Book 1
Tab 1a
Installation, Start-Up and
Service Instructions
CONTENTS
Page
SAFETY CONSIDERATIONS . . . . . . . . . . . . . . . . . . . . . . 1
INSTALLATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-58
Step 1 — Provide Unit Support . . . . . . . . . . . . . . . . . . . 1
• ROOF CURB
• ALTERNATE UNIT SUPPORT
Step 2 — Rig and Place Unit
. . . . . . . . . . . . . . . . . . . . . 2
• POSITIONING
• ROOF MOUNT
Step 3 — Field Fabricate Ductwork
. . . . . . . . . . . . . . . 2
Step 4 — Make Unit Duct Connections . . . . . . . . . . . 2
Step 5 — Install Flue Hood . . . . . . . . . . . . . . . . . . . . . . 28
Step 6 — Trap Condensate Drain . . . . . . . . . . . . . . . . 28
Step 7 — Install Gas Piping . . . . . . . . . . . . . . . . . . . . . 28
Step 8 — Controls Options . . . . . . . . . . . . . . . . . . . . . . 29
• STAGED GAS UNIT APPLICATIONS
• THERMISTORS
• CONSTANT VOLUME APPLICATIONS
• VARIABLE AIR VOLUME (VAV) APPLICATIONS
Step 9 — Make Electrical Connections
. . . . . . . . . . 33
• POWER WIRING
• FIELD POWER SUPPLY
• FIELD CONTROL WIRING
Step 10 — Make Outdoor-Air Inlet
Adjustments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48
• ECONOMIZER
• ECONOMIZER SETTINGS
Step 11 — Position Power Exhaust/Barometric
Relief Damper Hood . . . . . . . . . . . . . . . . . . . . . . . . . . . 52
Step 12 — Install All Accessories . . . . . . . . . . . . . . . 54
Step 13 — Field Modifications . . . . . . . . . . . . . . . . . . . 57
START-UP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58-89
SERVICE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89-102
TROUBLESHOOTING . . . . . . . . . . . . . . . . . . . . . . . 103-115
START-UP CHECKLIST . . . . . . . . . . . . . . . . . . . CL-1,CL-2
SAFETY CONSIDERATIONS
Installation and servicing of air-conditioning equipment can
be hazardous due to system pressure and electrical compo-
nents. Only trained and qualified service personnel should in-
stall, 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 per-
sonnel. 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 extinguishers available for all brazing operations.
INSTALLATION
Step 1 — Provide Unit Support
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, service,
or maintenance can cause property damage, personal
injury, or loss of life. Refer to the User’s Information
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 hazardous
condition. If gas valve is subjected to pressure greater than
0.5 psig, it must be replaced before use. 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).
1. All panels must be in place when rigging.
2. Unit is not designed for handling by fork truck.
48AJ,AK,AW,AY020-060
with Reciprocating Compressor
48EJ,EK,EW,EY024-068
Single Package Rooftop Units
Electric Cooling/Gas Heating