Carrier 50ZHA024-060 User Manual

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Installation, Start-Up and Service Instructions

NOTE: Read the entire instruction manual before starting the

installation.

TABLE OF CONTENTS

SAFETY CONSIDERATIONS .....................................................1

INTRODUCTION ..........................................................................2

RECEIVING AND INSTALLATION ..........................................2

Check Equipment......................................................................2

IDENTIFY UNIT ................................................................2

INSPECT SHIPMENT ........................................................2

Provide Unit Support ................................................................2

SLAB MOUNT ...................................................................2

GROUND MOUNT ............................................................2

Provide Clearances....................................................................2

Place Unit..................................................................................2

Select and Install Ductwork .....................................................2

CONVERTING HORIZONTAL DISCHARGE
UNITS TO DOWNFLOW (VERTICAL) DIS-

CHARGE ..................................................................4

Provide for Condensate Disposal .............................................4

Install Electrical Connections...................................................5

HIGH-VOLTAGE CONNECTIONS..................................5

ROUTING POWER LEADS INTO UNIT ........................6

CONNECTING GROUND LEAD TO UNIT GROUND .6

ROUTING CONTROL POWER WIRES ..........................6

ACCESSORY ELECTRIC HEAT WIRING .....................6

PRE-START-UP ............................................................................6

START-UP .....................................................................................7

Check for Refrigerant Leaks ....................................................8

LOCATE AND REPAIR REFRIGERANT LEAKS AND

CHARGE THE UNIT AS FOLLOWS: .............................8

Start-Up Cooling Section and Make Adjustments ..................8

CHECKING COOLING CONTROL OPERATION .........8

Refrigerant Charge....................................................................8

NO CHARGE......................................................................8

LOW CHARGE COOLING ...............................................9

HEATING MODE CHARGE.............................................9

Indoor Airflow and Airflow Adjustments................................9

FOR 208/230-V .................................................................13

Unit Controls...........................................................................13

HIGH-PRESSURE RELIEF VALVE...............................13

LOSS OF CHARGE SWITCH.........................................13

COMPRESSOR OVERLOAD..........................................13

Sequence of Operation............................................................13

FAN OPERATION............................................................13

COOLING..........................................................................14

HEATING..........................................................................14

CONTINUOUS FAN ........................................................14

DEFROST..........................................................................14

ELECTRIC RESISTANCE HEATING............................14

MAINTENANCE.........................................................................15

Air Filter..................................................................................15

Unit Top Removal (Outdoor-Coil Side) ................................15

50ZHA024-060

Packaged Heat Pump Units

A05194

Fig. 1—Unit 50ZHA

Indoor Blower and Motor.......................................................15

Outdoor Coil, Indoor Coil, and Condensate Drain Pan ........16

Outdoor Fan ............................................................................16

Electrical Controls and Wiring...............................................16

Refrigerant Circuit ..................................................................17

Indoor Airflow ........................................................................17

Metering Devices ....................................................................17

Lubrication ..............................................................................17

Liquid Line Strainer................................................................17

High Flow Valves...................................................................17

TROUBLESHOOTING ...............................................................17

START-UP CHECKLIST............................................................17

NOTE TO INSTALLER—Before installation, READ THESE
INSTRUCTIONS CAREFULLY AND COMPLETELY. Also,
make sure the User’s Manual and Replacement Guide are left with
the unit after installation.

SAFETY CONSIDERATIONS

Installation and servicing of air-conditioning equipment can be
hazardous due to system pressure and electrical components. Only
trained and qualified workers should install, repair, or service
air-conditioning equipment.

Untrained workers can perform basic maintenance functions of
cleaning coils and filters. All other operations should be performed
by trained service people. When working on air-conditioning
equipment, pay attention to precautions in the literature, tags, and
labels attached to the unit, and other safety precautions that may
apply.

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

Book 1 4
Tab 6 8

PC 101 Printed in U.S.A. Catalog No. 50ZHA-1SI Pg 1 9-05 Replaces: New

Follow all safety codes. Wear safety glasses and work gloves. Use
quenching cloth for unbrazing operations. Have fire extinguisher
available for all brazing operations.

FIRE, EXPLOSION, ELECTRICAL SHOCK HAZARD
Failure to follow this warning could result in personal injury,
death and/or property damage.
Before performing service or maintenance operations on
system, turn off main power to unit and install lockout tag.
Turn off accessory heater power switch if applicable.

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

Understand the signal words DANGER, WARNING, CAUTION,
and NOTE. These words are used with the safety-alert symbol.
DANGER identifies the most serious hazards which will result in
severe personal injury or death. WARNING signifies a hazard
which could result in personal injury or death. CAUTION is used
to identify unsafe practices which may result in minor personal
injury or product and property damage. NOTE is used to highlight
suggestions which will result in enhanced installation, reliability,
or operation.

These instructions cover minimum requirements and conform to
existing national standards and safety codes. In some instances,
these instructions exceed certain local codes and ordinances,
especially those that may not have kept up with changing residen­tial construction practices. We require these instructions as a
minimum for a safe installation.

INTRODUCTION

50ZHA heat pump units are fully self-contained and designed for
outdoor installation (See Fig. 1). As shown in Fig. 2, units are
shipped in a horizontal-discharge configuration for installation on
a ground-level slab. All units can be field-converted to downflow
discharge configurations for rooftop applications with a field­supplied plenum.

RECEIVING AND INSTALLATION

Step 1—Check Equipment

IDENTIFY UNIT

The unit model number and serial number are stamped on the unit
identification plate. Check this information against shipping pa­pers. Verify that unit voltage and amperage listed on unit rating
plate agree with power supplied for equipment.

INSPECT SHIPMENT

Inspect for shipping damage while unit is still on shipping pallet.
If unit appears to be damaged or is torn loose from its securing
points, have it examined by transportation inspectors before
removal. Forward claim papers directly to transportation company.
Manufacturer is not responsible for any damage incurred in transit.

Check all items against shipping list. Immediately notify the
nearest Carrier Distributor if any item is missing.

To prevent loss or damage, leave all parts in original packages
until installation.

Step 2—Provide Unit Support

SLAB MOUNT

Place the unit on a rigid, level surface, suitable to support the unit
weight. A concrete pad or a suitable fiberglass mounting pad is
recommended. The flat surface should extend approximately 2-in.
beyond the unit casing on the 2 sides. The duct connection side and
condensate drain connection sides should be flush with the edge of
the flat surface.

A 6-in. wide gravel apron should be used around the flat surface to
prevent airflow blockage by grass or shrubs. Do not secure the unit
to the flat surface except where required by local codes.

The unit should be level to within 1/4 inch. This is necessary for
the unit drain to function properly.

GROUND MOUNT

The unit may also be installed directly on the ground if local codes
permit. Place unit on level ground prepared with gravel for
condensate discharge.

HURRICANE HOLD DOWN

Contact you local distributor for specific hurricane hold down
details and PE (Professional Engineer) certification when required.

Step 3—Provide Clearances

The required minimum service clearances and clearances to
combustibles are shown in Fig. 2. Adequate ventilation and
outdoor coil air must be provided.

The outdoor fan pulls air through the outdoor coil and discharges
it through the fan on the top cover. Be sure that the fan discharge
does not recirculate to the outdoor coil. Do not locate the unit in
either a corner or under an overhead obstruction. The minimum
clearance under a partial overhang (such as a normal house
overhang) is 48 in. above the unit top. The maximum horizontal
extension of a partial overhang must not exceed 48 inches.

Do not place the unit where water, ice, or snow from an overhang
or roof will damage or flood the unit. The unit may be installed on
wood flooring or on Class A, B, or C roof covering materials.

OPERATIONAL HAZARD
Failure to follow this caution may result in unit component
damage.
Do not restrict outdoor coil airflow. An air restriction at either
the outdoor-air inlet or the fan discharge can be harmful to
compressor life.

Step 4—Place Unit

Unit can be moved with the rigging holds provided in the unit base.
Refer to Table 2 for operating weights. Use extreme caution to

prevent damage when moving the unit. Unit must remain in an
upright position during all moving operations. The unit must be

level with in 1/4” for proper condensate drainage; the ground-level
pad must be level before setting the unit in place. When a
field-fabricated support is used, be sure that the support is level
and that it properly supports the unit.

Step 5—Select and Install Ductwork

The design and installation of the duct system must be in
accordance with:

• the standards of the NFPA (National Fire Protection Associa­tion) for installation of nonresidence-type air conditioning and
ventilating systems

• NFPA90A or residence-type, NFPA90B; and/or local codes
and residence-type, NFPA 90B

• and/or local codes and ordinances

Select and size ductwork, supply-air registers and return-air grilles
according to ASHRAE (American Society of Heating, Refrigera­tion, and Air Conditioning Engineers) recommendations.

Use the duct flanges provided on the supply- and return-air
openings on the side of the unit. See Fig. 2 for connection sizes and
locations. The 14-in. round duct collars are shipped inside the unit
attached to the base pan in the indoor blower compartment. They

2

A05201

Fig. 2—Unit Base Dimensions, 50ZHA024-060

3

Table 1—Unit Specifications

UNIT ELECTRICAL CHARACTERISTICS

50ZHA024 208/230-1-60 293 133 30.13 (765) 14.0 (356) 19.0 (483) 12.0 (305)
50ZHA030 208/230-1-60 324 147 34.13 (867) 14.0 (356) 19.0 (483) 12.0 (305)
50ZHA036 208/230-1-60 377 171 42.13 (1070) 14.0 (356) 19.0 (438) 19.8 (503)
50ZHA042 208/230-1-60 389 177 42.13 (1070) 14.0 (356) 19.0 (483) 21.9 (556)
50ZHA048 208/230-1-60 384 175 42.13 (1070) 14.0 (356) 19.0 (483) 19.8 (503)
50ZHA060 208/230-1-60 433 197 42.13 (1070) 14.0 (356) 19.0 (483) 21.9 (556)

UNIT WEIGHT

lb kg ″A″ XYZ

UNIT HEIGHT

IN. (MM)

CENTER OF GRAVITY IN. (MM)

are field-installed and must be removed from the indoor blower
compartment prior to start-up, even if they are not used for
installation.

When designing and installing ductwork, consider the following:

UNIT DAMAGE HAZARD
Failure to follw this caution may result in damage to unit
components. When connecting ductwork to units, do not drill
deeper than 3/4 inch in shaded area shown in Fig. 3 or coil
may be damaged.

• All units should have field-supplied filters installed in the
return-air side of the unit. Recommended sizes for filters are
shown in Table 2.

• Avoid abrupt duct size increases and reductions. Abrupt change
in duct size adversely affects air performance.

IMPORTANT: Use flexible connectors between ductwork and
unit to prevent transmission of vibration. Use suitable gaskets to
ensure weathertight and airtight seal. When electric heat is
installed, use fire proof canvas (or similar heat resistant material)
connector between ductwork and unit discharge connection. If
flexible duct is used, insert a sheet metal sleeve inside duct. Heat
resistant duct connector (or sheet metal sleeve) must extend 24–in.
from the unit discharge connection flange into the ductwork.

• Size ductwork for cooling air quantity (cfm). The minimum air
quantity for proper electric heater operation is listed in Table 3.
Heater limit switches may trip at air quantities below those
recommended.

• Insulate and weatherproof all external ductwork. Insulate and
cover with a vapor barrier all ductwork passing through
conditioned spaces. Follow latest Sheet Metal and Air Condi­tioning Contractors National Association (SMACNA) and Air
Conditioning Contractors Association (ACCA) minimum in­stallation standards for residential heating and air conditioning
systems.

• Secure all ducts to building structure. Flash, weatherproof, and
vibration-isolate duct openings in wall or roof according to
good construction practices.

Figure 4 shows a typical duct system with 50ZHA unit installed.

CONVERTING HORIZONTAL DISCHARGE UNITS TO
DOWNFLOW (VERTICAL) DISCHARGE

ELECTRICAL SHOCK HAZARD
Failure to follow this warning could result in personal injury
or death.
Before performing service or maintenance operations on
system, turn off main power to unit and install lockout tag.
Turn off accessory heater power switch if applicable.

Units are dedicated side supply products. They are not convertible
to vertical air supply. A field-supplied plenum must be used to
convert to vertical air discharge.

Step 6—Provide for Condensate Disposal

NOTE: Be sure that condensate-water disposal methods comply

with local codes, restrictions, and practices.

Unit removes condensate through a 1 3/64-in. ID hole (using
3/4-in. OD piping or tubing) which is located at the end of the unit.
See Fig. 2 for location of condensate connection.

19.17

3.92

Fig. 3—Area Not to Be Drilled More Than 3/4-in.

Condensate water can be drained directly onto the roof in rooftop
installations (where permitted) or onto a gravel apron in ground­level installations. Install a field-supplied condensate trap at end of
condensate connection to ensure proper drainage. Make sure that
the outlet of the trap is at least 1 in. lower than the drain-pan
condensate connection to prevent the pan from overflowing. Prime
the trap with water. When using a gravel apron, make sure it slopes
away from the unit.

If the installation requires draining the condensate water away
from the unit, install a 2-in. trap using a 3/4-in. OD tubing or pipe.
(See Fig. 5 and 6.) Make sure that the outlet of the trap is at least
1 in. lower than the unit drain-pan condensate connection to
prevent the pan from overflowing. Prime the trap with water.
Connect a drain tube using a minimum of 3/4-in. PVC, 3/4-in.
CPVC, or 3/4-in. copper pipe (all field supplied). Do not undersize
the tube. Pitch the drain tube downward at a slope of at least 1 in.
for every 10 ft of horizontal run. Be sure to check the drain tube
for leaks. Prime trap at the beginning of the cooling season
start-up. Allowable glues for condensate trap connection are:
Standard ABS, CPVC, or PVC cement.

4

A05195

Table 2—Physical Data

UNIT 50ZHA 024 030 036 042 048 060

OPERATING WEIGHT (lbs) 293 324 377 389 384 433

COMPRESSOR TYPE Scroll Ultra Tech Scroll

15.8

20

4.9
Direct Drive

R-22

Propeller

Round

14
14

2...21

15.8

3200

20

1/4 (1100)

4...17

6.1

1400

11x9

3/4 (1050)

2...21

13.3

3200

20

1/4 (1100)

4...17

4.9

1600

11x10

1 (1050)

2...21

15.8

3300

20

1/2 (1100)

4...17

6.1

1875

11x10

1 (1050)

REFRIGERANT Charge (lb)

REFRIGERANT METERING DEVICE

*Required filter sizes shown are based on the ARI (Air Conditioning and Refrigeration Institute) rated airflow at a velocity of 300 ft/min for throwaway type or 450 ft/min

for high capacity type. Recommended filters are 1-in. thick.

Orifice ID (in.)

Orifice OD (in.) .049 .057 .059 .063 .070 .073

CONDENSER COIL

Rows...Fins/in.

Face Area (sq. ft.)

CONDENSER FAN

Nominal Cfm

Diameter (in.)

Motor HP (RPM)

EVAPORATOR COIL

Face Area (sq. ft.)

Evaporator Blower

Nominal Airflow (CFM)

Size (in.)

Motor HP (RPM)

CONNECTING DUCT SIZES

Supply Air (in.)
Return Air (in.)

Return-Air Filters (in.)*

Throwaway

7.5 10.3 10.3 11.9 11.4 13.3
Accurater TXV

.067 .067 .082 .086 — —

Copper Tubes, Aluminum Plate Fins

2...21

11.1

2600

20

1/8 (825)

3...17

4.3

800

10x8

1/2 (1050)

24x24 24x24 24x24 24x30 30x30 30x30

2...21

12.7

2600

20

1/8 (825)

3...17

4.9

1000

10x8

1/2 (1050)

2...21

3200

1/4 (1100)

Copper Tubes, Aluminum Plate Fins

4...17

1200

11x9

3/4 (1050)

Step 7—Install Electrical Connections

ELECTRICAL SHOCK HAZARD
Failure to follow this warning could result in personal injury
or death.
The unit cabinet must have an uninterrupted, unbroken
electrical ground to minimize the possibility of personal
injury if an electrical fault should occur. This ground may
consist of an electrical wire connected to the unit ground in
the control compartment, or conduit approved for electrical
ground when installed in accordance with NEC (National
Electrical Code), ANSI (American National Standards
Institute)/NFPA (latest edition) (in Canada, Canadian Elec­trical Code CSA C22.1) and local electrical codes.

UNIT DAMAGE HAZARD
Failure to follow these precautions may result in damage to
the unit being installed:

1. Make all electrical connections in accordance with NEC
ANSI/NFPA (latest edition) and local electrical codes
governing such wiring. In Canada, all electrical connec­tions must be in accordance with CSA standard C22.1
Canadian Electrical Code Part 1 and applicable local
codes. Refer to unit wiring diagram.

2. Use only copper conductor for connections between
field-supplied electrical disconnect switch and unit. DO
NOT USE ALUMINUM WIRE.

3. Be sure that high-voltage power to unit is within operating
voltage range indicated on unit rating plate.

4. Insulate low-voltage wires for highest voltage contained
within conduit when low-voltage control wires are run in
same conduit as high-voltage wires.

5. Do not damage internal components when drilling through
any panel to mount electrical hardware, conduit, etc.
Consult local power company for correction of improper
voltage.

HIGH-VOLTAGE CONNECTIONS

The unit must have a separate electrical service with a field­supplied, waterproof disconnect switch mounted at, or within sight
from the unit. Refer to the unit rating plate for maximum
fuse/circuit breaker size and minimum circuit amps (ampacity) for
wire sizing. See Table 6 for electrical data.

The field-supplied disconnect may be mounted on the unit over the
high-voltage inlet hole. (See Fig. 2.)

5

INDOOR
THERMOSTAT

RETURN
AIR

TOP COVER

Power Wiring

Control Wiring

Condenser Airflow

Evaporator Airflow

POWER AND
LOW-VOLTAGE
ENTRY

COMPOSITE
RUST-PROOF
BASEPAN

CONDENSATE
DRAIN
CONNECTION

*Separate disconnect per NEC
(National Electrical Code) required
for electric heater when single­point conection is not used.

FROM
POWER
SOURCE

DISCONNECT
PER NEC*
(UNIT AND
ELECTRIC
HEATER)

C00008

C00008

Fig. 4—Typical installation

1” (25mm) MIN.

TRAP
OUTLET

2” (50mm) MIN.

C99013

Fig. 5—Condensate Trap (Using Tubing)

TRAP
OUTLET

1" min.

2" min.

C00009

Fig. 6—PVC Condensate Trap

Table 3—Minimum Airflow for Safe Electric Heater

Operation (CFM)

SIZE 024 030 036 042 048 060

Cfm 600 750 900 1050 1200 1500

UNIT DAMAGE HAZARD
Failure to follow this caution may result in unit component
damage. Operation of unit on improper line voltage consti­tutes abuse and may cause unit damage that could affect
warranty.

ROUTING POWER LEADS INTO UNIT

Use only copper wire between disconnect and unit. The high­voltage leads should be in a conduit until they enter the unit;
conduit termination at the unit must be watertight. Run the
high-voltage leads through the hole on the control box side of the
unit (see Fig. 7 for location). When the leads are inside the unit,
run leads to the control box (Fig. 8). For single-phase units,
connect leads to the black and yellow wires (see Fig. 9).

CONNECTING GROUND LEAD TO UNIT GROUND

Refer to Fig. 8 and 9. Connect the ground lead to the chassis using
the unit ground in the control box.

ROUTING CONTROL POWER WIRES

Form a drip-loop with the thermostat leads before routing them
into the unit. Route the thermostat leads through grommeted hole
provided in unit into unit control box (See Fig. 7). Connect
thermostat leads and unit power leads as shown in Fig. 9, 10A &
10B.

Route thermostat wires through grommet providing a drip-loop at
the panel. Connect low-voltage leads to the thermostat as shown in
Fig. 10A & 10B.

The unit transformer supplies 24-v power for complete system
including accessory electrical heater. Transformer is factory wired
for 230-v operation.

ACCESSORY ELECTRIC HEAT WIRING

Refer to accessory electric heat installation instructions for infor­mation on installing accessory electric heat. Accessory electric
heat wiring is shown in Fig. 11A, 11B, & 11C.

PRE-START-UP

FIRE, EXPLOSION, ELECTRICAL SHOCK HAZARD
Failure to observe the following warnings could result in
serious injury, death and/or property damage:

1. Follow recognized safety practices and wear protective
goggles when checking or servicing refrigerant system.

2. Do not operate compressor or provide any electric power to
unit unless compressor terminal cover is in place and
secured.

3. Do not remove compressor terminal cover until all electri­cal sources are disconnected and lockout tag is installed.

4. Relieve all pressure from both high- and low-pressure sides
of the system before touching or disturbing anything inside
terminal box if refrigerant leak is suspected around com­pressor terminals. Use accepted methods to recover refrig­erant.

5. Never attempt to repair soldered connection while refrig­erant system is under pressure.

6. Do not use torch to remove any component. System
contains oil and refrigerant under pressure. To remove a
component, wear protective goggles and proceed as fol­lows:
a. Shut off electrical power to unit and install lockout tag.
b. Relieve all refrigerant from system using both high- and

low-pressure ports. Use accepted methods to recover
refrigerant.

c. Cut component connecting tubing with tubing cutter and

remove component from unit.

d. Carefully unsweat remaining tubing stubs when neces-

sary. Oil can ignite when exposed to torch flame.

Use the Start-Up Checklist supplied at the end of this book and
proceed as follows to inspect and prepare the unit for initial
start-up:

1. Remove all access panels.

2. Read and follow instructions on all DANGER, WARNING,
CAUTION, and INFORMATION labels attached to, or
shipped with unit.

Make the following inspections:

a. Inspect for shipping and handling damages such as broken

lines, loose parts, disconnected wires, etc.

6

Table 4—Required Subcooling

REQUIRED SUBCOOLING °F (°C)

Model Size

048 17.5 (9.7) 17 (9.4) 16.5 (9.2) 16 8.9) 14 (7.8)
060 21 (11.7) 20.5 (11.4) 20 (11.1) 19 (10.6) 16 (8.9)

75 (24) 82 (28) 85 (29) 95 (35) 105 (41)

Outdoor Ambient Temperature

Table 5—Required Liquid Line Temperature

REQUIRED LIQUID LINE TEMPERATURE FOR A SPECIFIC SUBCOOLING (R-22)

Pressure (psig)

134 71 66 61 56 924 24 22 19 16
141 74 69 64 59 972 26 23 21 18
156 80 75 70 65 1075 30 27 24 21
163 83 78 73 68 1124 31 28 26 23
170 86 81 76 71 1172 33 30 27 24
177 89 84 79 74 1220 34 31 29 26
184 91 86 81 76 1268 36 33 30 27
191 94 89 84 79 1317 37 34 31 29
198 96 91 86 81 1365 38 36 33 30
205 98 93 88 83 1413 40 37 34 31
213 101 96 91 86 1468 41 38 36 33
221 104 99 94 89 1524 43 40 37 34
229 106 101 96 91 1579 44 41 38 36
237 108 103 98 93 1634 45 42 40 37
245 111 106 101 96 1689 47 44 41 38
253 113 108 103 98 1744 48 45 42 40
262 116 111 106 101 1806 49 46 44 41
271 118 113 108 103 1868 51 48 45 42
280 121 116 111 106 1930 52 49 46 44
289 123 118 113 108 1992 53 51 48 45
298 125 120 115 110 2054 55 52 49 46
307 128 123 118 113 2116 56 53 50 48
317 130 125 120 115 2185 57 54 52 49
327 132 127 122 117 2254 59 56 53 50
337 135 130 125 120 2323 60 57 54 52
347 137 132 127 122 2392 61 58 56 53
357 139 134 129 124 2461 62 60 57 54
367 142 137 132 127 2530 64 61 58 55
280 121 116 111 106 1930 52 49 46 44
289 123 118 113 108 1992 53 51 48 45
298 125 120 115 110 2054 55 52 49 46
307 128 123 118 113 2116 56 53 50 48
317 130 125 120 115 2185 57 54 52 49
327 132 127 122 117 2254 59 56 53 50
337 135 130 125 120 2323 60 57 54 52
347 137 132 127 122 2392 61 58 56 53
357 139 134 129 124 2461 62 60 57 54
367 142 137 132 127 2530 64 61 58 55

Required Subcooling (°F)

5 101520 36811

Pressure (kPa)

Required Subcooling (°C)

b. Inspect for oil at all refrigerant tubing connections and on

unit base. Detecting oil generally indicates a refrigerant
leak. Leak-test all refrigerant tubing connections using
electronic leak detector, or liquid-soap solution. If a refrig­erant leak is detected, see following Check for Refrigerant
Leaks section.

c. Inspect all field- and factory-wiring connections. Be sure

that connections are completed and tight. Ensure wires do
not contact refrigerant tubing or sheet metal edges.

d. Inspect coil fins. If damaged during shipping and handling,

carefully straighten fins with a fin comb.

3. Verify the following conditions:

a. Make sure that outdoor-fan blade is correctly positioned in

fan orifice. Top edge of blade should be 3.125 in. down
from outdoor coil outlet grille (size 024–048, See Fig. 12)
or hub should be 0.708-in. away from motor end bell (size
060, See Fig. 13). See Outdoor Fan Adjustment section.

b. Make sure that air filter is in place.

c. Make sure that condensate drain trap is filled with water to

ensure proper drainage.

d. Make sure that all tools and miscellaneous loose parts have

been removed.

7

HIGH-VOLTAGEPOWER

WIRINGENTRYHOLE

LOW-VOLTAGEWIRING

ENTRYHOLE

A05198

Fig. 7—Unit Electrical Connection

C00011

Fig. 8—Control Box Wiring

START-UP

Use the Start-Up Checklist supplied at the end of this book and
proceed as follows:

Step 1—Check for Refrigerant Leaks

LOCATE AND REPAIR REFRIGERANT LEAKS AND
CHARGE THE UNIT AS FOLLOWS:

1. Using both high- and low-pressure ports, locate leaks and
reclaim remaining refrigerant to relieve system pressure.

2. Repair leak following accepted practices.

NOTE: Install a liquid-line filter drier whenever the system has
been opened for repair.

Step 2—Start-Up Cooling Section and Make Adjustments

UNIT DAMAGE HAZARD
Failure to follow this caution may result in unit component
damage.
Complete the required procedures given in the Pre-Start- Up
section this page before starting the unit. Do not jumper any
safety devices when operating the unit.
Do not operate the compressor in cooling mode when the
outdoor temperature is below 40 F.
Do not rapid-cycle the compressor. Allow 5 minutes between
‘‘on’’ cycles to prevent compressor damage.

CHECKING COOLING CONTROL OPERATION

Start and check the unit for proper cooling control operation as
follows:

1. Place room thermostat SYSTEM switch in OFF position.
Observe that blower motor starts when FAN switch is placed
in ON position and shuts down within 60 seconds (for
024-042) or 90 seconds (for 048 and 060) when FAN switch
is placed in AUTO position.

2. Place SYSTEM switch in COOL position and FAN switch in
AUTO position. Set cooling control below room temperature.
Observe that compressor, outdoor fan, and indoor blower
motors start and that reversing valve shifts. Observe that
cooling cycle shuts down when control setting is satisfied.
Reversing valve (RV) remains energized.

3. Place system switch in HEAT position. Observe that compres­sor, indoor fan and outdoor fan energize (Reversing Valve is
deenergized in heat pump heating mode). Set control above
room temperature. Observe that heating cycle shuts down
when control setting is satisfied.

4. When using an automatic changeover room thermostat, place
both SYSTEM and FAN switches in AUTO. positions.
Observe that unit operates in Cooling mode when temperature
control is set to ‘‘call for cooling’’ (below room temperature),
and unit operates in Heating mode when temperature control
is set to “call for heating” (above room temperature).

Step 3—Refrigerant Charge

Refrigerant Charge — Amount of refrigerant charge is listed on
unit nameplate and in Table 2. Refer to Carrier Refrigerant Service
Techniques Manual, Refrigerants section. Unit panels must be in
place when unit is operating during charging procedure. Unit must
operate a minimum of 15 minutes before checking charge.

NO CHARGE

Refer to Carrier Refrigerant Service Techniques. Use standard
evacuating techniques. After evacuating system, weigh in the
specified amount of refrigerant (refer to Table 2).

UNIT GROUND

GROUND

LEAD

3-PHASE
CONNECTIONS
TO DISCONNECT
PER NEC

Fig. 9—Line Power Connections

SINGLE-PHASE
CONNECTIONS
TO DISCONNECT
PER NEC

L

L

L

BLK

YEL

BLU

C00012

8

Thermostat

G

Y

W2

W3

R

RED

GREEN

O

ORANGE

C

BROWN

WHITE

VIOLET

G

Y

Y1

O

R

RED

GREEN

YELLOW

W2

PINK

W3

ORANGE

WHITE

VIOLET

C

BROWN

and subbase

Unit Control

Power

A05207

Fig. 10A—Control Connections (Sizes 024-042)

3. Insulate the temperature sensing device so that the outdoor
ambient doesn’t affect the reading.

4. Locate the measured suction line pressure in the top row of
Table 8 and the measured outdoor ambient temperature in the
left column of the table. Based on the two values, determine
the required suction line temperature.

5. If the measured suction line temperature is greater than the
tabulated temperature, add charge in the system.

048 and 060 units:

1. Measure discharge line pressure by attaching a gauge to the
service port.

2. Measure the liquid line temperature by attaching a temperature
sensing device to it.

3. Insulate the temperature sensing device so that the outdoor
ambient doesn’t affect the reading.

4. Refer to the required subcooling in Tables 4 and 5 to find the
required subcooling based on the model size and the outdoor
ambient temperature.

5. Interpolate if the outdoor temperature lies in between the table
values. Extrapolate if the temperature lies beyond the table
range.

6. Find the pressure value corresponding to the measured pres­sure on the compressor discharge line.

7. Read across from the pressure reading to obtain the Liquid line
temperature for a required subcooling.

8. Add charge if the measured temperature is higher than the
liquid line temperature value in the table.

9. Add charge using the service connection on the suction line of
the compressor.

HEATING MODE CHARGE

Do not attempt to adjust charge by cooling methods while in heat
pump heating mode. Recover refrigerant and weigh in according to
unit data plate refrigerant data.

Step 4—Indoor Airflow and Airflow Adjustments

NOTE: For cooling operation, the recommended airflow is 350 to

450 cfm per each 12,000 Btuh of rated cooling capacity.

Table 7 shows dry coil air delivery for horizontal discharge units.
Tables 9-11 show pressure drops.

NOTE: Be sure that all supply- and return-air grilles are open,
free from obstructions, and adjusted properly.

Thermostat

and subbase

Unit Control

Power

A05208

Fig.10B—Control Connections (Sizes 048-060)

LOW CHARGE COOLING

024-042 units:

1. Measure suction line pressure by attaching a gauge to the
service port.

2. Measure the suction line temperature by attaching a tempera­ture sensing device to it.

ELECTRICAL SHOCK HAZARD
Failure to follow this warning could result in personal injury
or death.
Disconnect electrical power to the unit and install lockout tag
before changing blower speed.

Airflow can be changed by changing the 24 volts lead connections
of the blower motor.

Unit 50ZHA blower motors are factory wired for rated airflow
operation.

FOR 208/230-V BLOWER MOTORS

The motor lead speed connections are as follows:

SIZE RATED AIRFLOW HIGH AIRFLOW

024 Tap 1 Tap 3
030 Tap 2 Tap 4
036 Tap 1 Tap 3
042 Tap 2 Tap 4

9

Fig. 11A—Typical Unit Electrical Diagram (Sizes 024-042)

10

A05199

Fig. 11B—Typical Unit Electrical Diagram (Sizes 048-060)

11

A05200

A05209

Fig. 11C—Accessory Electric Heater Wiring

Table 6—Electrical Data—50ZHA

VOLTAGE

UNIT SIZE

50ZHA

024 208/230–1–60 187 253 10.9 54.0 0.9 4.1

030 208/230–1–60 187 253 13.5 72.5 0.9 4.1

036 208/230–1–60 187 253 17.5 88.0 1.5 6.0

042 208/230–1–60 187 253 19.4 104.0 1.5 6.0

048 208/230–1–60 187 253 24.7 116.0 1.5 7.7

060 208/230–1–60 187 253 28.0 118.0 3.0 7.7

FLA Full Load Amps
LRA Locked Rotor Amps
MCA Minimum Circuit Amps
MOCP Maximum Overcurrent Protection
RLA Rated Load Amps

NOTES:

1. In compliance with NEC (National Electrical Code) requirements for multimotor and combination load equipment (refer to NEC Articles 430 and 440), the overcurrent
protective device for the unit shall be Power Supply fuse. The CGA (Canadian Gas Association) units may be fuse or circuit breaker.

2. Minimum wire size is based on 60 C copper wire. If other than 60 C wire is used, or if length exceeds wire length in table, determine size from NEC.

V-PH-HZ

RANGE

MIN MAX RLA LRA Nominal KW* FLA MCA

COMPRESSOR

OFM

FLA

IFM

FLA

ELECTRIC HEAT SINGLE POINT POWER SUPPLY

FUSE OR
CKT BKR

—/—

3.8/5.0

7.5/10.0

5.4/7.2

—/—

3.8/5.0

7.5/10.0

11.3/15.0

5.4/7.2

—/—

3.8/5.0

7.5/10.0

11.3/15.0

5.4/7.2

—/—

3.8/5.0

7.5/10.0

11.3/15.0

15.0/20.0

5.4/7.2

—/—

3.8/5.0

7.5/10.0

11.3/15.0

15.0/20.0

5.4/7.2

—

3.8/5.0

7.5/10.0

11.3/15.0

15.0/20.0

5.4/7.2

—/—

18.1/20.8

36.1/41.7

26.0/30.0

—/—

18.1/20.8

36.1/41.7

54.2/62.5

26.0/30.0

—/—

18.1/20.8

36.1/41.7

54.2/62.5

26.0/30.0

—/—

18.1/20.8

36.1/41.7

54.2/62.5

72.2/83.3

26.0/30.0

—/—

18.1/20.8

36.1/41.7

54.2/62.5

72.2/83.3

26.0/30.0

—/—

18.1/20.8

36.1/41.7

54.2/62.5

72.2/83.3

26.0/30.0

18.6/18.6

41.2/44.7

63.8/70.7

51.1/56.1

21.8/21.8

44.4/47.9

57.0/73.9

89.5/100.0

54.3/59.3

29.4/29.4

52.0/55.4

74.5/81.5

97.1/107.5

61.9/66.9

31.7/31.7

54.3/57.8

76.9/83.8

99.4/109.9

122.0/135.9

63.2/69.2

40.0/40.0

62.6/66.1

85.1/92.1

107.7/118.1

130.3/144.2

72.5/77.5

45.7/45.7

68.2/71.7

90.8/97.8

113.4/123.8

135.9/149.9

78.2/83.2

25/25
45/50

—

50/50

30/30
50/50

—
—

60/60

35/35
60/60

—
—
—

40/40

—
—
—
—
—

50/50

—
—
—
—
—

60/60

—
—
—
—
—

MOCP

—
—

60/70

—

—
—

70/70

90/100

—

—
—

80/80

100/100

70/70

—
60/70
80/90

100/110
110/150

70/80

—
80/80

100/100
110/125
125/125

90/90

—
90/90

100/110
125/125
125/150

90/100

12

Table 7—Dry Coil Air Delivery* Horizontal Discharge

(Deduct 10 percent for 208 Volt Operation)

50ZHA SPEED TAP WATTS/C.F.M

1

024

2

2

030

3

1

036

2

3

042

4

1

2

048

3

4

1

2

060

3

4

Air delivery values are based on operating voltage of 230-v., dry coil, without filter or electric heater. Deduct wet coil, filter, and electric heater pressure drops to obtain
external static pressure availabe for ducting.
Do not operate the unit at a cooling airflow that is less than 350 cfm for each 12,000 Btuh of rated cooling capacity. Evaporator coil frosting may occur at airflows below
this point.
Dashes indicate portions of the table that are beyond the blower motor capacity or are not recommended.

Watts -99100118130142----

C.F.M. -848793757698632----

Watts -----222233244257260

C.F.M -----970918861795729

Watts -155146157170-----

C.F.M - 1108 995 951 884 -----

Watts -----261275286291315

C.F.M. -----1117 1053 1014 980 877

Watts 180166179191204216----

C.F.M. 1344 1215 1172 1136 1095 1051 ----

Watts - - - 261 276 290 301 316 329 342

C.F.M. - - - 1343 1304 1272 1234 1190 1148 1100

Watts 269 283 305 321 336 349 360 - - -

C.F.M. 1440 1404 1369 1333 1301 1273 1239 - - -

Watts - - 418 432 450 465 480 490 503 518

C.F.M. - - 1572 1543 1504 1475 1441 1418 1380 1332

Watts — 204 209 216 229 236 249 — — —

C.F.M. — 1129 1087 1027 994 932 881 — — —

Watts — — 233 245 254 266 276 289 — —

C.F.M. — — 1164 1122 1066 1025 954 906 — —

Watts 386 398 409 418 425 435 438 441 451 —

C.F.M. 1680 1652 1625 1583 1555 1515 1477 1444 1403 —

Watts — 440 448 457 462 469 477 480 485 486

C.F.M. — 1745 1717 1684 1651 1612 1573 1537 1508 1470

Watts 224 235 251 266 277 291 298 - - -

C.F.M. 1334 1288 1259 1224 1181 1157 1117 - - -

Watts - - 286 301 311 325 333 344 370 -

C.F.M. - - 1333 1296 1261 1232 1199 1170 1062 -

Watts 608 626 643 660 668 685 697 - - -

C.F.M. 1931 1900 1878 1844 1817 1789 1755 - - -

Watts 737 755 770 787 799 817 826 812 782 -

C.F.M. 2093 2061 2028 2001 1971 1934 1899 1850 1757 -

0.1 0.2 .03 0.4 0.5 0.6 0.7 0.8 0.9 1.0

EXTERNAL STATIC PRESSURE

RATED AIRFLOW HIGH AIRFLOW

SIZE

048 Tap 1 Tap 3 Tap 2 Tap 4
060 Tap 1 Tap 3 Tap 2 Tap 4

Low

Stage

High

Stage

Low

Stage

High

Stage

Step 5—Unit Controls

All compressors have the following internal-protection controls.

HIGH-PRESSURE RELIEF VALVE

This valve opens when the pressure differential between the low
and high side becomes excessive.

LOSS OF CHARGE SWITCH

Located on the outdoor liquid line is a low-pressure switch which
functions as a loss-of-charge switch. This switch contains a
Schrader core depressor. This switch opens at 7 psig and closes at
22 psig. No adjustment is necessary.

COMPRESSOR OVERLOAD

This overload interrupts power to the compressor when either the
current or internal temperature become excessive, and automati­cally resets when the internal temperature drops to a safe level.

This overload may require up to 60 minutes (or longer) to reset;
therefore, if the internal overload is suspected of being open,
disconnect the electrical power to the unit and check the circuit
through the overload with an ohmmeter or continuity tester.

Step 6—Sequence of Operation

FAN OPERATION

The FAN switch on the thermostat controls indoor fan operation.
When the FAN switch is placed in the ON position, the IFR
(indoor-fan relay) is energized through the G terminal on the
thermostat. The normally-open contacts close, which then provide
power to the indoor (evaporator) fan motor (IFM). The IFM will
run continuously when the FAN switch is set to ON.

When the FAN switch is set to AUTO, the thermostat deenergizes
the IFR (provided there is not a call for cooling). The contacts open
and the IFM is deenergized. The IFM will be energized only when
there is a call for cooling, in heat pump heating mode or if the unit
is equipped with accessory electric heat, the indoor-fan motor will
also run while the accessory electric heat is energized.

NOTE: Some units are equipped with a time-delay relay. On
these units, the indoor fan remains on for 30 seconds after G or Y
is deenergized.

13

Table 8—Cooling Charging Chart

SUCTION LINE TEMPERATURE (°F)

Suction Line Pressure (PSIG)

OD Temp. (°F) 52 54 56 59 61 64 67 70 73 76 79 82 85 89 92

45 51 55606469——————————
55 — —5357626670————————
65 — ———535762667175—————
75 — ——————5661667176———
85 — ———————5358636772——

95 — ————————5054586266—
105 — —————————5053576064
115 — —————————4952555861
125 — ——————————50535659

SUCTION LINE TEMPERATURE (°C)

Suction Line Pressure (kPa)

OD Temp. (°C) 361 370 387 405 423 442 462 482 502 523 544 566 589 612 636

7 11 13151821——————————
13 — —1214161921————————
18 — ———121417192124—————
24 — ——————1316192224———
29 — ———————1214172022——
35 — ————————1012141719—
41 — —————————1012141618
46 — ————————— 9 11131416
52 — ——————————10111315

COOLING OPERATION (SIZES 024-042)

With a call for cooling (Y/Y2), the indoor fan energizes immedi­ately whereas the contactor energizes aftera5minute time delay
(in case of initial start-up) starting the compressor and the outdoor
fan motor. When the cooling demand is met, Y/Y2 de-energizes,
shutting the compressor, indoor fan and the outdoor fan.

COOLING OPERATION (SIZES 048 AND 060)

These units utilize a 2 stage indoor thermostat. With a first stage
call for cooling (Y1), the indoor fan (low stage) energizes
immediately whereas the contactor energizes aftera5minute time
delay (in case of an initial start-up) starting the compressor (low
stage) and the outdoor fan motor. If the low stage operation cannot
satisfy the cooling demand, the second stage cooling (Y2) ener­gizes switching the compressor into high stage cooling through
energizing an internal solenoid valve inside the scroll compressor
and switching the indoor fan into high stage. When second stage
cooling is satisfied, Y2 de-energizes switching the compressor and
the indoor fan into low stage cooling. When the low stage cooling
demand is met, Y1 de-energizes shutting the compressor, indoor
fan and the outdoor fan.

HEATING OPERATION (SIZES 024-042)

With a call for heating (Y1), the indoor fan (low stage) energizes
immediately whereas the contactor energizes aftera5minute time
delay (in case of initial start-up) starting the compressor and the
outdoor fan motor. If Y/Y2 cannot satisfy the heating demand, the
auxiliary or backup heat (W2) energizes. In case of staged heating,
W3 is energized if the demand is not met. The highest airflow
selected is run while the electric heat is in operation. When heating
demand is met, W3, W2 and Y/Y2 sequentially de-energize
shutting the compressor, indoor fan and the outdoor fan.

HEATING OPERATION (SIZES 048 AND 060)

With a first stage call for heating (Y1), the indoor fan (low stage)
energizes immediately whereas the contactor energizes after a 5
minute time delay (in case of initial start-up) starting the compres­sor (low stage) and the outdoor fan motor. If the low stage
oepration cannot satisfy the heating demand, the second stage

heating (Y2) energizes switching the compressor into high stage
heating through energizing an internal solenoid valve inside the
scroll compressor and switching the indoor fan into high stage. The
auxiliary or backup heat is controlled by a third stage (W2). If the
demand is not met, W3 is energized in case of staged heating.
When heating demand is satisfied, W3, W2 and Y2 sequentially
de-energize switching the compressor and the indoor fan into low
stage heating. When the low stage heating demand is met, Y1
de-energizes shutting the compressor, indoor fan and the outdoor
fan.

CONTINUOUS FAN

With the continuous Indoor fan option selected on the thermostat,
G is continuously energized. In case of 024-042 units, the selected
airflow setting is provided. In case of 048 and 060 units, the
system runs low stage (Y1) airflow for continuous fan operation.

DEFROST

Defrost board (DB) is a time and temperature control, which
includes a field-selectable time period between checks for defrost
(30, 60, 90 and 120 minutes). The time period is factory-set at 60
minutes and should only be adjusted by a trained service person.
Electronic timer and defrost cycle start only when contactor is
energized and defrost thermostat (DFT) is closed.

Defrost mode is identical to Cooling mode. The outdoor fan motor
stops because of “OF1” and “OF2” contacts opening on the defrost
board, a bank of optional electric heat turns on to warm air
supplying the conditioned space.

ELECTRIC RESISTANCE HEATING

If accessory electric heaters are installed, on a call for “Emergency
Heat” the thermostat energizes W which energizes the heater relay
and in turn energizes the electric heaters. The IFR is energized
which starts the indoor-fan motor. If the heaters are staged, W2 is
energized when the second stage of heating is required. When the
need for heating is satisfied, the heater and IFM are de-energized.

MAINTENANCE

To ensure continuing high performance, and to reduce the possi­bility of premature equipment failure, periodic maintenance must

14

be performed on this equipment. This cooling unit should be
inspected at least once each year by a qualified service person. To
troubleshoot cooling of units, refer to Troubleshooting chart in
back of book.

NOTE TO EQUIPMENT OWNER: Consult your local dealer
about the availability of a maintenance contract.

FIRE, EXPLOSION, ELECTRICAL SHOCK HAZARD
Failure to follow this warning could result in personal injury,
death or property damage.
The ability to properly perform maintenance on this equip­ment requires certain expertise, mechanical skills, tools and
equipment. If you do not possess these, do not attempt to
perform any maintenance on this equipment, other than those
procedures recommended in the User’s Manual.

The minimum maintenance requirements for this equipment are as
follows:

1. Inspect air filter(s) each month. Clean or replace when
necessary.

2. Inspect indoor coil, outdoor coil, drain pan, and condensate
drain each cooling and heating season for cleanliness. Clean
when necessary.

3. Inspect blower motor and wheel for cleanliness each cooling
and heating season. Clean when necessary. For first heating
season, inspect blower wheel bimonthly to determine proper
cleaning frequency.

4. Check electrical connections for tightness and controls for
proper operation each cooling season. Service when neces­sary.

5. Check the drain channel in the top cover periodically for
blockage (leaves, insects). Clean as needed.

FIRE, EXPLOSION, ELECTRICAL SHOCK, CUT HAZ­ARD
Failure to follow these warnings could result in serious
personal injury, death, and/or property damage:

1. Turn off electrical power to the unit and install lockout tag
before performing any maintenance or service on the unit.

2. Use extreme caution when removing panels and parts. As
with any mechanical equipment, personal injury can result
from sharp edges, etc.

3. Never place anything combustible either on, or in contact
with, the unit.

Step 1—Air Filter
NOTE: Never operate the unit without a suitable air filter in the

return-air duct system. Always replace the filter with the same size
as originally installed. See Table 2 for recommended filter sizes.

Inspect air filter(s) at least once each month and replace
(throwaway-type) or clean (cleanable-type) at least twice during
each cooling season or whenever the filters become clogged with
dust and lint.

Replace filters with the same dimensional size and type as
originally provided, when necessary.

Step 2—Unit Top Removal (Outdoor-Coil Side)
NOTE: When performing maintenance or service procedures that

require removal of the unit top, be sure to perform all of the routine
maintenance procedures that require top removal, including coil
inspection and cleaning, and condensate drain pan inspection and
cleaning.

ELECTRICAL SHOCK HAZARD
Failure to follow this warning could result in personal injury
or death.
Disconnect and tag electrical power to the unit before
removing top.

Only qualified service personnel should perform maintenance and
service procedures that require unit top removal.

Refer to the following top removal procedures:

1. Remove screws on unit top cover surface. (Save all screws.)

2. Remove screws on unit top cover flange. (Save all screws.)

3. Lift top from unit carefully. Set top on edge and make sure
that top is supported by unit side that is opposite duct (or
plenum) side.

4. Carefully replace and secure unit top to unit, using screws
removed in Steps 1 and 2, when maintenance and/or service
procedures are completed.

Step 3—Indoor Blower and Motor

For longer life, operating economy, and continuing efficiency,
clean accumulated dirt and grease from the blower wheel and
motor annually.

ELECTRICAL SHOCK HAZARD
Failure to follow this warning could result in personal injury
or death.
Disconnect and tag electrical power to the unit before
cleaning the blower wheel.

To clean the blower wheel follow the following steps:

1. Remove the blower housing:

a. Remove the screws on the external side of the duct panel

that fasten the housing to the duct panel assembly.

b. Remove the side access panel and unscrew the mounting

bracket that fastens the blower housing to the internal
partition panel fo the control box assembly.

c. Make sure that the blower housing is supported by hand

before completely removing the mounting bracket.

d. Slide the blower housing from the rails of the duct panel

and place it outside the unit.

2. Remove the blower wheel from the housing:

a. Loosen the set screw which secures the wheel to the motor

shaft.

b. Loosen the three mounting legs of the motor by removing

the bolts that fasten themounting legs to the housing.

c. Slide out the motor assembly (motor, belly band and the 3

mounting legs) from the hub of the wheel.

d. Remove the filler panel at the discharge end of the blower

housing by removing the two screws that fasten it to the
housing.

e. Remove the wheel form the housing.

3. Remove the caked on dirt from the wheel and the motor using
a brush.

4. Remove lint and dirt accumulations from the wheel and
housing with a vacuum cleaner, using a soft brush attachment.

5. Remove grease and oil with a mild solvent.

6. Reassemble

15

Table 9—Wet Coil Pressure Drop

UNIT SIZE

024 .027.034040.047.053---------­030 - .036 .042 .050 .055 .063 .072 .081 - - - - - - ­036 - - - .050 .055 .063 .072 .081 .090 .097 - - - - ­042 - - - - .042 .049 .052 .059 .065 .071 .078 .085 .091 - ­048 - - - - - - .072 .081 .090 .097 .108 .120 .129 .139 ­060 - - - - - - - - - .071 .078 .085 .091 .098 .114

600 700 800 900 1000 1100 1200 1300 1400 1500 1600 1700 1800 1900 2000

STANDARD CFM (S.C.F.M.)

a. Slip the wheel back in the housing with the hub set screw

parented in the correct direction.

b. Install the filler panel.

c. Reinsert the motor assembly in the wheel hub and align the

mounting legs with the housing mounting hold locations.

d. Tighten the mounting bolts to fasten the motor assembly

with the housing.

e. Center the wheel in the housing by sliding it, align the flat

end of the shaft with the set screw and tighten the set screw.

f. Slide back the blower housing into the mounting rails in the

duct panel and install the mounting bracket back in its
position.

g. Install the screws on the external side of the duct panel to

fasten duct panel with the housing.

h. Replace the side access panel.

Step 4—Outdoor Coil, Indoor Coil, and Condensate
Drain Pan

Inspect the outdoor coil, indoor coil, and condensate drain pan at
least once heating and cooling season. Proper inspection and
cleaning requires the removal of the unit top. See Unit Top
Removal section.

Table 10—Filter Pressure Drop (in. wg)

FILTER

UNIT
SIZE

024-036 24 x 24 0.06 0.07 0.08 0.08 0.09 0.09 0.09 0.10 0.11 0.12

042-060 30x30----- - - -0.080.09

SIZE

500 600 700 800 900 1000 1100 1200 1300 1400

(IN.)

CFM

coil fins from inside to outside the unit. On units with an outer and
inner outdoor coil, be sure to clean between the coils. Be sure to
flush all dirt and debris from the unit base.

Inspect the drain pan and condensate drain line when inspecting
the coils. Clean the drain pan and condensate drain by removing all
foreign matter from the pan. Flush the pan and drain tube with
clear water. Do not splash water on the insulation, motor, wiring,
or air filter(s). If the drain tube is restricted, clear it with a
‘‘plumbers snake’’ or similar probe device. Ensure that the
auxiliary drain port above the drain tube is also clear.

Step 5—Outdoor Fan

UNIT OPERATIONAL HAZARD
Failure to follow this caution may result in damage to unit
components.
Keep the Outdoor fan free from all obstructions to ensure
proper cooling operation. Never place articles on top of the
unit.

1. Shut off unit power supply and install lockout tag.

2. Remove outdoor-fan assembly (grille, motor, motor cover,
and fan) by removing screws and flipping assembly onto unit
top cover.

3. Loosen fan hub setscrews.

4. Adjust fan height as shown in Fig. 12 or 13.

5. Tighten setscrews.

6. Replace outdoor-fan assembly.

FILTER

UNIT
SIZE

024-036 24x240.140.15-------

042-060 30 x 30 0.10 0.11 0.12 0.13 0.14 0.15 0.16 0.17 0.18

SIZE

1500 1600 1700 1800 1900 2000 2100 2200 2300

(IN.)

CFM

Table 11—Accessory Electric Heat Pressure Drop

(in. wg)

HEATER KW

5-20

600 800 1000 1200 1400 1600 1800 2000 2200

0.06 0.08 0.10 0.13 0.15 0.18 0.20 0.23 0.25

Remove all obstructions (including weeds and shrubs) that inter­fere with the airflow through the outdoor coil. Straighten bent fins
with a fin comb. If coated with dirt or lint, clean the coils with a
vacuum cleaner, using a soft brush attachment. Be careful not to
bend the fins. If coated with oil or grease, clean the coils with a
mild detergent-and-water-solution. Rinse coils with clear water,
using a garden hose. Be careful not to splash water on motors,
insulation, wiring or air filter(s). For best results, spray outdoor-

CFM

Step 6—Electrical Controls and Wiring

Inspect and check the electrical controls and wiring annually. Be
sure to turn off the electrical power to the unit and install lockout
tag.

Remove the top panel to locate all the electrical controls and
wiring. Check all electrical connections for tightness. Tighten all
screw connections. If any smoky or burned connections are
noticed, disassemble the connection, clean all the parts, restrip the
wire end and reassemble the connection properly and securely.

3.125 in.

C00021

Fig. 12—Outdoor-Fan Adjustment (024–048 Size)

Check to ensure no wires are touching refrigerant tubing or sharp
sheet metal edges. Move and secure wires to isolate from tubing
and sheet metal edges.

16

0.708in.

C02017

Fig. 13—Outdoor-Fan Adjustment (060 Size)

After inspecting the electrical controls and wiring, replace all the
panels. Start the unit, and observe at least one complete cooling
cycle to ensure proper operation. If discrepancies are observed in
operating cycle, or if a suspected malfunction has occurred, check
each electrical component with the proper electrical instrumenta­tion. Refer to the unit wiring label when making these checkouts.

NOTE: Refer to the Sequence of Operation section, as an aid in
determining proper control operation.

Step 7—Refrigerant Circuit

Inspect all refrigerant tubing connections and the unit base for oil
accumulations annually. Detecting oil generally indicates a refrig­erant leak.

If oil is detected or if low cooling performance is suspected,
leak-test all refrigerant tubing using an electronic leak-detector, or
liquid-soap solution. If a refrigerant leak is detected, refer to Check
for Refrigerant Leaks section. (See Table of Contents for page
number.)

If no refrigerant leaks are found and low cooling performance is
suspected, refer to Refrigerant Charge. (See Table of Contents for
page number.)

Step 8—Indoor Airflow

The cooling airflow does not require checking unless improper
performance is suspected. If a problem exists, be sure that all

supply- and return-air grilles are open and free from obstructions,

and that the air filter is clean. When necessary, refer to Indoor

Airflow and Airflow Adjustments section to check the system
airflow.

Step 9—Metering Devices

Refrigerant cooling metering device is an Accurator (024-042) or
TXV (048 and 060) located upstream of the indoor coil distributor
assembly. Refrigerant heating mode metering device is an Accu­rater located upstrem of the outdoor coil distributor assembly.

Step 10—Lubrication

COMPRESSOR—The compressor is charged with the correct
amount of oil at the factory.

FAN MOTOR BEARINGS—Fan motor bearings are perma­nently lubricated. No further lubrication of outdoor or indoor fan
motors is required.

Step 11—Liquid Line Strainer

The liquid line strainer (to protect metering device) is made of wire
mesh and is located in the liquid line on the inlet side of the
metering device.

Check valves are also located in the liquid lines near the strainers.
The Strainers are the larger of the two components.

Step 12—High Flow Valves

Located on the compressor hot gas and suction tubes are High
Flow Valves. Large black plastic caps distinguish these valves
with O-rings located inside the caps. These valves cannot be
accessed for service in the field. Ensure the plastic caps are in
place and tight or the possibility of refrigerant leakage could occur.

TROUBLESHOOTING

Use the Troubleshooting Cooling and Heating guide if problems
occur with these units.

START-UP CHECKLIST

Use the Start-Up checklist to ensure proper start-up procedures are
followed.

17

OUTDOOR COIL

INDOOR COIL

B

A

ACCUMULATOR

COMPRESSOR

Check Valves

A

Open

B

Closed

C

Open

D

Closed

LCS Loss of Charge Switch

LEGEND

Acutrol Metering Device

Check Valve (Arrow indicates direction of flow)

HEATING CYCLE

1. Hot gas from compressor flows through the 4-way valve and is
directed to thecooling liquid line check valve.It is then condensed
and directed through subcooling circuits and out to the strainer
and the check valve in the heating liquid line.

2. The refrigerant then feeds the outdoor coil through the Acutrol
metering device on each circuit.

Fig. 14—Typical Heat Pump Operation, Heating Mode

OUTDOOR COIL

LCS

STRAINER

D

STRAINER

C

3. Each circuit evaporates the refrigerant and the circuits are com­bined in theoutdoor header with someof the circuits flowing through
the check valve.

4. The refrigerant then flows through the 4-way valve, accumulator,
and back to the compressor.

INDOOR COIL

C95045

A

ACCUMULATOR

COMPRESSOR

Check Valves

A

Closed

B

Open

C

Closed

D

Open

LCS Loss of Charge Switch

LEGEND

Acutrol Metering Device

Check Valve (Arrow indicates direction of flow)

COOLING CYCLE

1. Hot gas from compressor flows through the 4-way valve and is
directed to the heating liquid line check valve. It is then con­densed and subcooledthrough converging circuits. Refrigerantleaves
the outdoor coil by way of the strainer and the check valve in the
cooling liquid line.

2. The refrigerant then feeds the indoor coil through the Acutrol
metering device on each circuit.

Fig. 15—Typical Heat Pump Operation, Cooling Mode

B

LCS

STRAINER

D

STRAINER

C

3. Each circuit evaporates the refrigerant and the circuits are com­bined in the indoor coil header with some of the circuits flowing
through the check valve.

4. The refrigerant then flows through the 4-way valve, accumulator,
and back to the compressor.

C95044

18

Table 12—Troubleshooting—Cooling and Heating

SYMPTOM CAUSE REMEDY

Compressor and outdoor fan will not start.

Compressor will not start but outdoor fan

(other than normally satisfying thermostat).

Compressor operates continuously.

Excessive head pressure.

Head pressure too low.

Excessive suction pressure.

Suction pressure too low.

runs.

Compressor cycles

Compressor runs but
outdoor fan does not.

Power Failure Call power company

Loss of Charge

Switch open

Fuse blown or circuit breaker tripped Replace fuse or reset circuit breaker

Defective thermostat, contractor, transformer, or

Faulty wiring or loose connections in compressor

Compressor motor burned out, seized, or internal

Defective run/start capacitor, overload, start relay Determine cause and replace

Refrigerant overcharge or undercharge

Defective run/start capacitor, overload or start

Faulty outdoor-fan motor or capacitor Replace

Restriction in refrigerant system Locate restriction and remove

Frosted outdoor coil with incorrect

Metering device or low side restricted Remove source of restriction

Insufficient indoor airflow (cooling)

Temperature too low in conditioned area (cooling) Reset thermostat

Outdoor ambient below 40°F (cooling) Install low-ambient kit

Field-installed filter-drier restricted Replace

control relay

Insufficient line voltage Determine cause and correct

Incorrect or faulty wiring Check wiring diagram and rewire correctly

Thermostat setting too high

circuit

overload open

Low input voltage

(20 percent low)

Loss of Charge

Switch open

Defective compressor Replace and determine cause

Insufficient line voltage Determine cause and correct

Blocked outdoor coil (cooling) Determine cause and correct

relay

Defective thermostat Replace thermostat

Dirty air filter Replace filter

Unit undersized for load Decrease load or increase unit size

Thermostat set too low Reset thermostat

Low refrigerant charge Locate leak, repair, and recharge

Leaking valves in compressor Replace compressor

defrost operation (heating)

Air in refrigerant system

outdoor coil dirty or restricted Clean coil or remove restriction

Dirty air filter Replace filter

Dirty outdoor coil Clean coil

Refrigerant overcharged Recover excess refrigerant

Air in refrigerant system

Outdoor or indoor air restricted

or air is recirculating

Low refrigerant charge Check for leaks, repair and recharge

Compressor valves leaking Replace compressor

Restriction in liquid tube Remove restriction

High heat load Check for source and eliminate

Compressor valves leaking Replace compressor

Refrigerant overcharged Recover excess refrigerant

Dirty air filter (cooling) Replace Filter

Low refrigerant charge Check for leaks, repair, and recharge

Normally closed contacts on

defrost board open

Evaluate unit for possible refrigerant leak

Replace component

Lower thermostat setting below room tempera-

Check wiring and repair or replace

Determine cause and correct

Recover refrigerant, evacuate system, and re-

charge to capacities shown on nameplate

Evaluate unit for possible refrigerant leak

Determine cause and replace

Check defrost time settings. Reset as necessary.

Check defrost temperature switch. Replace as necessary.

Recover refrigerant, evacuate system, and re-

Recover refrigerant, evacuate system, and re-

Determine cause and correct

Check filter- replace if necessary

Check condition of relay on board.

Replace board if necessary.

ture

Determine cause

Replace compressor

charge

charge

Increase air quantity

19

START-UP CHECKLIST

(REMOVE AND STORE IN JOB FILE)

I. PRELIMINARY INFORMATION

Model No .............................................................................................................................................................

Serial No ..............................................................................................................................................................

Date ......................................................................................................................................................................

Technician ...........................................................................................................................................................

Customer Information(Name/Address) ...........................................................................................................................................................

II. PRE-START-UP

____ Verify that all packing materials have been removed from unit
____ Verify that condensate connection is installed per installation instructions
____ Check all electrical connections and terminals for tightness
____ Check wire proximity to refrigerant tubes and sheet metal edges
____ Check that indoor (indoor) air filter is clean and in place
____ Verify that unit installation is level
____ Check fan wheel propeller for location in housing and setscrew tightness

III. START-UP

Supply Voltage: L1-L2 __________ L2-L3 __________ L3-L1 __________
Compressor Amps: L1(C) __________ L2(S) __________ L3(R) __________
Indoor Fan Amps: __________ Outdoor Fan Amps: __________

TEMPERATURE-Cooling Mode

Outdoor Air Temperature: __________ DB ____________WB
Return-Air Temperature: __________ DB __________ WB
Cooling Supply Air: __________DB___________WB

PRESSURES-Cooling Mode

Refrigerant Suction __________ psig

Suction Line Temp* ___________

Refrigerant Discharge __________ psig

Discharge Temp†__________

TEMPERATURE-Heating Mode

Outdoor Air Temperature: __________ DB ____________WB
Return-Air Temperature: __________ DB __________ WB
Cooling Supply Air: __________DB___________WB

PRESSURES-Heating Mode

Refrigerant Suction __________ psig

Suction Line Temp* ___________

Refrigerant Discharge __________ psig

Discharge Temp†__________

____ Verify Refrigerant charge using charging tables

*Measured at suction inlet to compressor
†Measured at liquid line leaving outdoor coil

Copyright 2005 CARRIER Corp. • 7310 W. Morris St. • Indianapolis, IN 46231 50zha1si

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

Book 1 4
Tab 6 8

PC 101 Printed in U.S.A. Catalog No. 50ZHA-1SI Pg 20 9-05 Replaces: New