Carrier 38CKB User Manual

Installation and Start-Up Instructions

NOTE: Read the entire instruction manual before starting the

installation.

SAFETY CONSIDERATIONS

Improper installation, adjustment, alteration, service, maintenance,
or use can cause explosion, fire, electrical shock, or other
conditions which may cause death, personal injury, or property
damage. Consult a qualified installer, service agency, or your
distributor or branch for information or assistance. The qualified
installer or agency must use factory-authorized kits or accessories
when modifying this product. Refer to the individual instructions
packaged with the kits or accessories when installing.

Follow all safety codes. Wear safety glasses, protective clothing,
and work gloves. Use quenching cloth for brazing operations.
Have fire extinguisher available. Read these instructions thor­oughly and follow all warnings or cautions included in literature
and attached to the unit. Consult local building codes and national
electric codes for special requirements.

Recognize safety information. This is the safety-alert symbol
When you see this symbol on the unit and in instructions or
manuals, be alert to the potential for personal injury.

Understand the signal word DANGER, WARNING, or CAU­TION. These words are used with the safety-alert symbol. DAN­GER identifies the most serious hazards which willresultinsevere
personal injury or death. WARNING signifies hazards which
could result in personal injury or death. CAUTION is used to
identify unsafe practices which would result in minor personal
injury or product and property damage.

Before installing, modifying, or servicing system, main elec­trical disconnect switch must be in the OFF position. There
may be more than 1 disconnect switch. Lock out and tag
switch with a suitable warning label. Electrical shock can
cause personal injury or death.

INSTALLATION

Step 1—Check Equipment and Jobsite

UNPACK UNIT — Move to final location. Remove carton taking
care not to damage unit.

INSPECT EQUIPMENT — File claim with shipping company
prior to installation if shipment is damaged or incomplete. Locate
unit rating label on unit service panel. (See Fig. 2.) It contains
information needed to properly install unit. Check rating label to
be sure unit matches job specifications.

Step 2—Install on a Solid, Level Mounting Pad

If conditions or local codes require the unit be attached to pad,
tiedown bolts should be used and fastened through knockouts
provided in unit base pan. Refer to unit mounting pattern in Fig. 2
to determine base pan size and knockout hole location.

When installing, allow sufficient space for airflow clearance,
wiring, refrigerant piping, and service. Allow 30-in. (762mm)
clearance to service end of unit and 48 in. (1219mm) above unit.

38CKB—50 Hz

Air Conditioning Unit

A94356

Fig. 1—Model 38CKB

.

For proper airflow, a 6-in. (152mm) clearanceon1side of unit and
12 in. (305mm) on all remaining sides must be maintained.
Maintain a distance of 24 in. (610mm) between air conditioners.
Position so water, snow, or ice from roof or eaves cannot fall
directly on unit.

On rooftop applications, locate unit 6 in. (152mm) above roof
surface. Where possible, place unit above a load-bearing wall.

Arrange supporting members to adequately support unit and
minimize transmission of vibration to building. Consult local
codes governing rooftop applications.

Step 3—Replace Indoor AccuRater® Piston, if Required

Check indoor coil piston to see if it matches the required piston
shown on unit rating label. If it does not match, replace indoor coil
piston with piston shipped with this unit. The piston shipped with
outdoor unit is correct for any approved indoor coil combination.

Remove indoor coil piston if unit is to be installed on system
with a TXV metering device.

Step 4—Make Piping Connections

Outdoor units may be connected to indoor sections using accessory
tubing package or field-supplied refrigerant grade tubing of correct
size and condition. For tubing requirements beyond 50 ft (15.24m),
consult Long-Line Application Guideline which is available at
your local distributor.

NOTE: In some cases, noise in the living area has been traced to
gas pulsations from improper installation of equipment.

INSTALLATION RECOMMENDATIONS

1. Locate the unit away from windows.

2. Ensure that vapor and liquid tube diameters are appropriate to
the capacity of the unit. (See Table 1.)

Manufacturer reserves the right to discontinue, or change at any time, specifications or designs without notice and without incurring obligations.

Book 1 4
Tab 3a 2a

PC 101 Catalog No. 013-862 Printed in U.S.A. Form 38CKB-C1SI Pg 1 12-94 Replaces: New

AIR IN

AIR 

DISCHARGE

AIR IN

AIR IN

AIR 
DISCHARGE

AIR 

IN

NOTES:

1. Allow 30 in. (762) clearance to service sides of unit, 48 in.
(1219.2) above unit, 6 in. (152.4) on one side, 12 in. (304.8) on remaining
side, and 24 in. (609.6) between units for proper airflow.

2. Minimum outdoor operating ambient in cooling mode is 55 F (12.8 C),
max 115 F (46.1 C).

3. Dimensions in parenthesis are in millimeters.

4. Series designation is the 13th position of the unit model number.


A

AIR DISCHARGE

F DIA SUCTION LINE CONN

UNIT SIZE

018 18 457.2 3 76.2 15 381.0 10-3/16 258.8 5/8 15.9
024 22-1/2 571.5 3-11/16 93.6 18-1/8 460.4 14-3/8 365.1 5/8 15.9
036 22-1/2 571.5 3-11/16 93.6 18-1/8 460.4 14-3/8 365.1 3/4 19.1

048, 060 30 762.0 6-1/2 165.1 23-1/2 596.9 20 508.0 7/8 22.2

In. mm In. mm In. mm In. mm In. mm

AIR DISCHARGE

RATING LABEL

FIELD POWER 
SUPPLY CONN

7

⁄8 IN. DIA (22.22) HOLE WITH 
1 1⁄8 IN. DIA (28.57) KNOCKOUT
AND 1 3⁄8 IN. DIA (34.92) KNOCKOUT

FIELD CONTROL 
SUPPLY CONN

7

⁄

IN. DIA (22.22) HOLE

8


3

⁄8 IN. DIA (9.53) LIQUID LINE CONN

A/B C D E F



C

D



E

Fig. 2—Unit Reference Drawing

3. Run refrigerant tubes as directly as possible by avoiding
unnecessary turns and bends.

4. Leave some slack between the structure and the unit to absorb
vibration.

To prevent compressor damage DO NOT bury more than 36
in. (914mm) of refrigerant tubing. If ANY tubing is buried,
provide 6 in. (152mm) vertical rise at service valve.

5. When passing refrigerant tubes through the wall, seal the
opening with RTV or other pliable silicon-based caulk. (See
Fig. 3.)

6. Avoid direct lineset contact with water pipes, ductwork, floor
joists, wall studs, floors, and walls.

7. Do not suspend refrigerant tubing from joists and studs with a
rigid wire or strap which comes in direct contact with the
tubing. (See Fig. 3.)

OUTDOOR UNITS CONNECTED TO FACTORY-APPROVED
INDOOR UNITS — Outdoor unit contains correct system refrig­erant charge for operation with indoor unit of the same size when
connected by 15 ft (4.55m) of field-supplied or factory-accessory
tubing. Check refrigerant charge for maximum efficiency.

REFRIGERANT TUBING — Connect tubing to fittings on out­door unit vapor and liquid service valves. (See Fig. 2.)

8. Ensure that tubing insulation is pliable and completely sur­rounds the vapor tube.

9. When necessary, use hangar straps which are 1 in. (25mm)
wide and conform to the shape of the tubing insulation. (See
Fig. 3.)

10. Isolate the hangar straps from the insulation by using metal

Relieve pressure and recover all refrigerant before system
repair or final unit disposal to avoid personal injury or death.
Use all service ports and open all flow-control devices,
including solenoid valves.

sleeves bent to conform to the shape of the insulation.

If refrigerant tubes or indoor coil is exposed to atmospheric
conditions for longer than 5 minutes, it must be evacuated to 500
microns to eliminate contamination and moisture in the system.

2

B

A91173

Table 1—Refrigerant Connections and Recommended Liquid and Vapor Tube Diameters

LIQUID VAPOR

UNIT SIZE

018, 024 3/8 9.53 3/8 9.53 5/8 15.88 5/8 15.88

036 3/8 9.53 3/8 9.53 3/4 19.05 3/4 19.05
048 3/8 9.53 3/8 9.53 7/8 22.23 7/8 22.23
060 3/8 9.53 3/8 9.53 7/8 22.23 1-1/8 28.58

1. Tube diameters are for lengths up to 50 ft (15.24m). For tube sets over 50 ft (15.24m), consult Long-Line Application Guideline.

2. Do not apply capillary tube indoor coils to these units.

To prevent damage to unit or service valves observe the
following:

• Use a brazing shield.

• Wrap service valves with wet cloth or use a heat sink
material.

SWEAT CONNECTION — Use refrigerant grade tubing. Service
valves are closed from factory and ready for brazing. After
wrapping the service valve with a wet cloth, the tubing set can be
brazed to the service valve using either silver bearing or non-silver
bearing brazing material. Consult local code requirements. Refrig­erant tubing and indoor coil are now ready for leak testing. This
check should include all field and factory joints.

Connection Dia. Tube Dia. Connection Dia. Tube Dia.

In. mm In. mm In. mm In. mm

NOTE: Operation of unit on improper line voltage constitutes
abuse and could affect unit reliability. See unit rating label. Do not
install unit in system where voltage or phase imbalance may
fluctuate above or below permissible limits.

NOTE: Use copper wire only between disconnect switch and
unit.

NOTE: Install branch circuit disconnect per local codes of
adequate size to handle unit starting current. Locate disconnect
within sight from and readily accessible from unit per local codes.

To avoid personal injury or death, do not supply power to unit
with compressor terminal box cover removed.

Avoid contact between tubing and structure.NOTE:

OUTDOOR WALL INDOOR WALL

CAULK

INSULATION

THROUGH THE WALL

HANGER STRAP

(AROUND VAPOR

TUBE ONLY)

1″ MIN

(25 mm)

SUSPENSION

LIQUID TUBE

VAPOR TUBE

JOIST

INSULATION

VAPOR TUBE

LIQUID TUBE

The unit cabinet must have an uninterrupted or unbroken
ground to minimize personal injury if an electrical fault
should occur. The ground may consist of electrical wire or
metal conduit when installed in accordance with existing
electrical codes. Failure to follow this warning can result in an
electric shock, fire, or death.

ROUTE GROUND AND POWER WIRES — Remove access
panel and control box cover to gain access to unit wiring. Extend
wires from disconnect through power wiring hole provided and
into unit control box. (See Fig. 2.) Size wires per local codes, but
not smaller than minimum wire size shown on unit rating label.

CONNECT GROUND AND POWER WIRES — Connect ground
wire to ground connection in control box for safety. Connect
power wiring to contactor as shown in Fig. 4.

DISCONNECT
PER N.E.C. AND/OR
LOCAL CODES

CONTACTOR

FIELD POWER

WIRING

3 PHASE ONLY

BLUE

A94330

Fig. 3—Piping Installation

Step 5—Make Electrical Connections

Be sure field wiring complies with local and national fire, safety,
and electrical codes, and voltage to system is within limits shown
on unit rating label. Contact local power company for correction of
improper voltage. See unit rating label for recommended circuit
protection device.

FIELD GROUND

WIRING

GROUND
LUG

Fig. 4—Line Power Connections

NOTE: Use No. 18 AWG (American Wire Gage) color-coded,

insulated (35° C minimum) wire. If thermostat is located more than
100 ft (30.5m) from unit as measured along the control voltage
wires, use No. 16 AWG color-coded wires to avoid excessive
voltage drop.

3

A94025

CONNECT CONTROL WIRING — Route 24-v control wires
through control wiring grommet and connect to brown and blue
pigtails supplied in unit splice box. (See Fig. 5.)

Use furnace transformer, fan-coil transformer, or accessory trans­former for control power, 24-v/40va minimum.

NOTE: Use of available 24-v accessories may exceed the mini­mum 40-va power requirement. Determine total transformer load­ing and increase the transformer capacity or split the load with an
accessory transformer as required.

Step 6—Compressor Crankcase Heat

When equipped with a crankcase heater, energize heater a mini­mum of 24 hrs before starting unit. To energize heater only, set
thermostat to OFF position and close electrical disconnect to
outdoor unit.
A crankcase heater is required if the refrigerant tubing is longer
than 50 ft (15.24m).

Step 7—Install Electrical Accessories, If Any

Refer to the individual instructions packaged with the kit or
accessory when installing.

Step 8—Start-Up and Check Charge

To prevent compressor damage or personal injury, observe
the following:

• Do not overcharge system with refrigerant.

• Do not operate unit in a vacuum or at negative pressure.

• Do not disable low-pressure switch.
In scroll compressor applications:

• Dome temperatures may be hot.

• In 3 phase application, incorrect phasing will cause reverse
rotation, resulting in elevated noise levels, equalized pres­sures and reduced current draw. Correct by reversing power
connection L1 and L2 on contactor.

Do not vent refrigerant to atmosphere. Recover during system
repair or final unit disposal.

1. Fully back seat (open) liquid and vapor tube service valves.

2. Unit is shipped with valve stem(s) front seated and caps
installed. Replace stem caps after system is opened to refrig­erant flow (back seated). Replace caps finger-tight and tighten
additional 1/6 turn with wrench.

3. Close electrical disconnects to energize system.

4. Set room thermostat at desired temperature. Be sure set point
is below indoor ambient temperature.

5. Set room thermostat at COOL and fan switch at FAN or
AUTO, as desired. Operate unit for 15 minutes. Check system
refrigerant charge.

6. Factory charge is shown on unit rating label. Adjust charge by
following procedure shown on charging tables located on unit.

Step 9—Leave User’s Manual with Owner

For continued high performance and to minimize possible equip­ment failure, periodic maintenance MUST be performed on this
equipment.
Leave User’s Manual with owner. Explain system operation and
periodic maintenance requirements outlined in manual. Frequency
of maintenance may vary depending on geographic areas, such as
coastal applications which require more frequent maintenance.

To prevent personal injury wear safety glasses, protective
clothing, and gloves when handling refrigerant and observe
the following:

• Back seating service valves are not equipped with Schrader
valves. Fully back seat (counter clockwise) valve stem before
removing gage port cap.

• Front seating service valves are equipped with Schrader
valves.

4

THERMOSTAT THERMOSTAT FURNACE

R

R

R
MOTOR
POWER

M

G

Y

IFR

C

SUPPLY

TRANS

Y

W

C

G

Y

W

/

W1

COOLING ONLY ONE STAGE COOLING / GAS HEATING

THERMOSTAT FAN COIL THERMOSTAT INDOOR UNIT

R

R
C

G

Y

W

Y

W2

ONE STAGE COOLING / ELECTRIC HEAT

CG

R

R

C

G

Y

W

Y

W

ONE STAGE COOLING / HEATING

ACCESSORY LIQUID LINE SOLENOID

LLS

CG

CG

NOTES:

1. Wiring must conform to local codes.

2. LLS required on some units. See specific unit instructions.

3. Transformer required is 24-v, 40-va minimum. A 60-va or external power source may
be necessary when installing accessories.

4. When installing electronic thermostat, connect transformer common to thermostat C.

LEGEND:

C

– COMPRESSOR CONTACTOR

– LIQUID LINE SOLENOID

LLS

M

– INDOOR FAN MOTOR

TRANS

– TRANSFORMER

– INDOOR FAN RELAYIFR

Fig. 5—24-v Control Circuit Connections

A94331

5

Copyright 1994 CARRIER Corp. • 7310 W. Morris St. • Indianapolis, IN 46231 38ckbc1s

Manufacturer reserves the right to discontinue, or change at any time, specifications or designs without notice and without incurring obligations.

Book 1 4
Tab 3a 2a

PC 101 Catalog No. 013-862 Printed in U.S.A. Form 38CKB-C1SI Pg 6 12-94 Replaces: New