Carrier 48AJ User Manual
48AJ,AK,AW,AY020-060
Single Package Rooftop Units
Electric Cooling/Gas Heating
with Scroll Compressor and
COMFORTLINK™ Controls
Installation Instructions
WEATHERMAKER
®
CONTENTS
Page
SAFETY CONSIDERATIONS . . . . . . . . . . . . . . . . . . . . . . 1
INSTALLATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-36
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 . . . . . . . . . . . . . . . . . . . . . . 19
Step 6 — Trap Condensate Drain. . . . . . . . . . . . . . . . 19
Step 7 — Install Gas Piping . . . . . . . . . . . . . . . . . . . . . 19
Step 8 — Make Electrical Connections . . . . . . . . . . 20
•POWER WIRING
• FIELD POWER SUPPLY
• FIELD CONTROL WIRING
Step 9 — Make Outdoor-Air Inlet
Adjustments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
• ECONOMIZER AND FIXED OUTDOOR
AIR DAMPER
Step 10 — Position Power Exhaust/Barometric
Relief Damper Hood. . . . . . . . . . . . . . . . . . . . . . . . . . . 33
Step 11 — Route VAV Static Pressure Sensor . . . 34
Step 12 — Install All Accessories . . . . . . . . . . . . . . . 35
Step 13 — Field Modifications. . . . . . . . . . . . . . . . . . . 35
SAFETY CONSIDERATIONS
Installation and servicing of air-conditioning equipment can
be hazardous due to system pressure and electrical components. 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, 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.
WARNING
WARNING
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 vapors 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 neighbor’s phone. Follow the gas supplier’s instructions.
4. If you cannot reach your gas supplier, call the fire
department.
WARNING
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).
INSTALLATION
Step 1 — Provide Unit Support
CAUTION
1. All panels must be in place when rigging or damage
to unit may occur.
2. Unit is not designed for handling by fork truck.
Before performing service or maintenance operations on
unit, turn off main power switch to unit. Electrical shock
could cause personal injury.
Manufacturer reserves the right to discontinue, or change at any time, specifications or designs without notice and without incurring obligations.
Catalog No. 04-53480067-01 Printed in U.S.A. Form 48A-7SI Pg 1 8-09 Replaces: 48A-5SI
ROOF CURB — For vertical discharge units, assemble or install accessory roof curb in accordance with instructions
shipped with this accessory. See Fig. 1-3. 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 necessary to permit unit drain to function properly. Unit leveling tolerance is shown in Fig. 1-3.
Refer to Accessory Roof Curb Installation Instructions for
additional 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. 1-3. Improperly applied gasket can
also result in air leaks and poor unit performance.
ALTERNATE UNIT SUPPORT — When the preferred curb
or slab mount cannot be used, support unit with sleepers on perimeter, using unit curb support area. If sleepers cannot be
used, support long sides of unit (refer to Fig. 4-10) with a minimum number of 4-in. x 4-in. pads spaced as follows:
48AJ,AK,AW,AY020-035 units require 3 pads on each side;
48AJ,AK,AW,AY036-050 units require 4 pads on each side;
48AJ,AK,AW,AY051 and 060 units require 6 pads on each
side. Unit may sag if supported by corners only.
Step 2 — Rig and Place Unit — Inspect unit for
transportation damage. See Tables 1-6 for physical data and
specifications. File any claim with transportation agency.
Do not drop unit; keep upright. Use spreader bars over unit
to prevent sling or cable damage. This unit must be handled
with a crane and can not be handled by a fork truck. Level by
using unit frame as a reference; leveling tolerance is shown in
Fig. 1-3. See Fig. 10 for additional information. Unit operating
weight is shown in Table 2.
NOTE: On retrofit jobs, ductwork may be attached to the old
unit instead of a roof curb. Be careful not to damage ductwork
when removing old unit. Attach existing ductwork to roof curb
instead of unit.
Four lifting lugs are provided on the unit base rails as shown
in Fig. 4-10. Refer to rigging instructions on unit.
POSITIONING — Maintain clearance, per Fig. 4-10, around
and above unit to provide minimum distance from combustible
materials, proper airflow, and service access.
Do not install unit in an indoor location. Do not locate unit
air inlets near exhaust vents or other sources of contaminated
air. For proper unit operation, adequate combustion and ventilation air must be provided in accordance with Section 5.3 (Air
for Combustion and Ventilation) of the National Fuel Gas
Code, ANSI Z223.1 (American National Standards Institute).
Although unit is weatherproof, guard against water from
higher level runoff and overhangs.
Locate mechanical draft system flue assembly at least 4 ft
from any opening through which combustion products could
enter the building, and at least 4 ft from any adjacent building.
When unit is located adjacent to public walkways, flue assembly must be at least 7 ft above grade.
ROOF MOUNT — Check building codes for weight distribution requirements. See Fig. 11. Unit operating weight is shown
in Table 2.
Step 3 — Field Fabricate Ductwork — Secure all
ducts to building structure. Use flexible duct connectors between unit and ducts as required. Insulate and weatherproof all
external ductwork, joints, and roof openings with counter
flashing and mastic in accordance with applicable codes.
NOTE: Due to width of the horizontal supply and return ductwork, provisions should be made for servicing of the outdoor
air filters (i.e., catwalk over ductwork).
Ducts passing through an unconditioned space must be insulated and covered with a vapor barrier. Outlet grilles must not
lie directly below unit discharge. The return duct must have a
90-degree elbow before opening into the building space if the
unit is equipped with power exhaust.
To attach ductwork to roof curb, insert duct approximately
10 to 11 in. up into roof curb. Connect ductwork to 14-gage
roof curb material with sheet metal screws driven from inside
the duct.
Follow AMCA (Air Movement and Control Association)
guidelines relating to ductwork connections to the unit. These
guidelines recommend a minimum 2
ters of straight duct connected to supply air inlet and outlet
openings before any transitions, fittings, dampers, etc. Failure
to adhere to these guidelines may result in system effects which
can impact the unit’s ability to achieve published performance.
1
/2 equivalent duct diame-
WARNING
For vertical supply and return units, tools or parts could
drop into ductwork and cause an injury. Install a 90-degree
elbow turn in the supply and return ductwork between the
unit and the conditioned space. If a 90-degree elbow cannot
be installed, then a grille of sufficient strength and density
should be installed to prevent objects from falling into the
conditioned space.
Step 4 — Make Unit Duct Connections
48AJ AND AK UNITS — Unit is shipped for thru-thebottom duct connections. Field-fabricated ductwork should be
attached to the roof curb. Supply and return duct dimensions
are shown in Fig. 4-6. Air distribution is shown in Fig. 12.
Refer to installation instructions shipped with roof curb for
more information.
48AW AND AY UNITS — Remove shipping covers from
supply and return air openings. Attach field-supplied ductwork
to unit. Connect to the unit with a single duct for all supply
openings and with a single duct for all return openings.
Splitting of the airflow into branch ducts should not be done at
the unit. Sufficient duct length should be used prior to branching to ensure the air temperatures are well mixed within the
ductwork. See Fig. 7-9 for duct opening dimensions. Secure all
ducts to building structure. Air distribution is shown in Fig. 7-9
and Fig. 13.
Install accessory barometric relief or power exhaust in the
field-fabricated return ductwork. Refer to Step 10 — Position
Power Exhaust/Barometric Relief Damper Hood section on
page 33 for more information.
Instructions continued on page 19.
2
NOTES:
Fig. 1 — Roof Curb — 48AJ,AK020-035 Units
DUCT PRIOR TO ANY SUPPLY TAKE OFFS OR BRANCHES.
1. UNLESS OTHERWISE SPECIFIED, ALL DIMENSIONS ARE TO OUTSIDE OF PART.
2. ROOF CURB ACCESSORY CRRFCURB005A00 IS SHIPPED DISASSEMBLED.
3. ALL ROOF CURB PARTS ARE TO BE 14 GA. GALVANIZED STEEL.
4. UNITS WITH ELECTRIC HEAT MUST BE INSTALLED WITH A 90° ELBOW ON THE SUPPLY
5. DIMENSIONS IN [ ] ARE IN MILLIMETERS. ALL OTHER DIMENSIONS ARE IN INCHES.
a48-6715
3
NOTES:
Fig. 2 — Roof Curb — 48AJ,AK036-050 Units
DUCT PRIOR TO ANY SUPPLY TAKE OFFS OR BRANCHES.
1. UNLESS OTHERWISE SPECIFIED, ALL DIMENSIONS ARE TO OUTSIDE OF PART.
2. ROOF CURB ACCESSORY CRRFCURB005A00 IS SHIPPED DISASSEMBLED.
3. ALL ROOF CURB PARTS ARE TO BE 14 GA. GALVANIZED STEEL.
4. UNITS WITH ELECTRIC HEAT MUST BE INSTALLED WITH A 90° ELBOW ON THE SUPPLY
5. DIMENSIONS IN [ ] ARE IN MILLIMETERS. ALL OTHER DIMENSIONS ARE IN INCHES.
a48-6716
4
NOTES:
Fig. 3 — Roof Curb — 48AJ,AK051 and 060 Units
OUTSIDE OF PART.
ASSEMBLED.
SIONS ARE IN INCHES.
1. UNLESS OTHERWISE SPECIFIED, ALL DIMENSIONS ARE TO
2. ROOF CURB ACCESSORY CRRFCURB005A00 IS SHIPPED DIS-
3. ALL ROOFCURB PARTS ARE TO BE 14 GA. GALVANIZED STEEL.
4. DIMENSIONS IN [ ] ARE IN MILLIMETERS. ALL OTHER DIMEN-
a48-6717
5
* OPERATING WEIGHT INCLUDES LARGEST INDOOR FAN MOTOR, CU/AL COILS,
MODULATING POWER EXHAUST (VARIABLE AIR VOLUME), AND VARIABLE
FREQUENCY DRIVE (VARIABLE AIR VOLUME).
Fig. 4 — Base Unit Dimensions — 48AJ,AK020-035
1. WEIGHTS INCLUDE ECONOMIZER (STD).
NOTES:
TOP OF UNITS: NO OVERHANG
CONDENSER COIL: 4’ - 0“ [1219]
2. CENTER OF GRAVITY.
3. UNIT CLEARANCES:
ECONOMIZER SIDE: 6’ - 0” [1829]
HEAT SIDE: 4’’ - 0” [1219]
FILTER ACCESS SIDE: 10’ - 0” [3048] (FOR
REMOVAL OF EVAPORATOR COIL)
CLEARANCES, CONTACT CARRIER APPLICA-
TION ENGINEERING DEPARTMENT.
TACHED TO ACCESSORY ROOF CURB. IF UNIT
IS MOUNTED ON DUNNAGE, IT IS RECOM-
MENDED THAT THE DUCTS BE SUPPORTED
BY CROSS BRACES AS DONE ON ACCESSO-
RY ROOF CURB.
OTHER DIMENSIONS ARE IN INCHES.
4. FOR SMALLER SERVICE AND OPERATIONAL
5. BOTTOM DUCTS ARE DESIGNED TO BE AT-
6. DIMENSIONS IN [ ] ARE IN MILLIMETERS. ALL
a48-8235
6
* OPERATING WEIGHT INCLUDES LARGEST INDOOR FAN MOTOR, CU/AL COILS,
MODULATING POWER EXHAUST (VARIABLE AIR VOLUME), AND VARIABLE
FREQUENCY DRIVE (VARIABLE AIR VOLUME).
Fig. 5 — Base Unit Dimensions — 48AJ,AK036-050
TOP OF UNITS: NO OVERHANG
CONDENSER COIL: 4’ - 0“ [1219]
1. WEIGHTS INCLUDE ECONOMIZER (STD).
2. CENTER OF GRAVITY.
3. UNIT CLEARANCES:
OTES:
ECONOMIZER SIDE: 6’ - 0” [1829]
HEAT SIDE: 4’’ - 0” [1219]
FILTER ACCESS SIDE: 10’ - 0” [3048] (FOR
REMOVAL OF EVAPORATOR COIL)
CLEARANCES, CONTACT CARRIER APPLICA-
TION ENGINEERING DEPARTMENT.
TACHED TO ACCESSORY ROOF CURB. IF UNIT
IS MOUNTED ON DUNNAGE, IT IS RECOM-
MENDED THAT THE DUCTS BE SUPPORTED BY
CROSS BRACES AS DONE ON ACCESSORY
ROOF CURB.
OTHER DIMENSIONS ARE IN INCHES.
4. FOR SMALLER SERVICE AND OPERATIONAL
5. BOTTOM DUCTS ARE DESIGNED TO BE AT-
6. DIMENSIONS IN [ ] ARE IN MILLIMETERS. ALL
a48-8236
7
Fig. 6 — Base Unit Dimensions — 48AJ,AK051 and 060
8
NOTES:
Fig. 7 — Base Unit Dimensions — 48AW,AY020-035
TOP OF UNITS: NO OVERHANG
CONDENSER COIL: 4’ - 0“ [1219]
ECONOMIZER SIDE: 6’ - 0” [1829]
HEAT SIDE: 4’’ - 0” [1219]
FILTER ACCESS SIDE: 10’ - 0” [3048] (FOR REMOVAL OF
EVAPORATOR COIL)
CONTACT CARRIER APPLICATION ENGINEERING
DEPARTMENT.
SIONS ARE IN INCHES.
1. WEIGHTS INCLUDE ECONOMIZER (STD).
2. CENTER OF GRAVITY.
3. UNIT CLEARANCES:
4. FOR SMALLER SERVICE AND OPERATIONAL CLEARANCES,
5. DIMENSIONS IN [ ] ARE IN MILLIMETERS. ALL OTHER DIMEN-
A48-8380
9
* OPERATING WEIGHT INCLUDES LARGEST INDOOR FAN MOTOR, CU/AL COILS,
MODULATING POWER EXHAUST (VARIABLE AIR VOLUME), AND VARIABLE
FREQUENCY DRIVE (VARIABLE AIR VOLUME).
Fig. 8 — Base Unit Dimensions — 48AW,AY036-050
TOP OF UNITS: NO OVERHANG
CONDENSER COIL: 4’ - 0“ [1219]
ECONOMIZER SIDE: 6’ - 0” [1829]
1. WEIGHTS INCLUDE ECONOMIZER (STD).
2. CENTER OF GRAVITY.
3. UNIT CLEARANCES:
NOTES:
HEAT SIDE: 4’’ - 0” [1219]
FILTER ACCESS SIDE: 10’ - 0” [3048] (FOR REMOVAL
OF EVAPORATOR COIL)
ANCES, CONTACT CARRIER APPLICATION ENGINEER-
ING DEPARTMENT.
MENSIONS ARE IN INCHES.
4. FOR SMALLER SERVICE AND OPERATIONAL CLEAR-
5. DIMENSIONS IN [ ] ARE IN MILLIMETERS. ALL OTHER DI-
a48-8239
10
Fig. 9 — Base Unit Dimensions — 48AW,AY051 and 060
FOR CENTERS OF
GRAVITY, OPERATING
AND CORNER WEIGHTS,
SEE FIGURE 10
a48-8240
11
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