50ZH024-060
Packaged Heat Pump Units
Installation, Start-Up and Service Instructions
NOTE: Read the entire instruction manual before starting the
installation.
DEFROST..........................................................................15
ELECTRIC RESISTANCE HEATING............................15
MAINTENANCE.........................................................................15
Air Filter..................................................................................16
Unit Top Removal (Outdoor-Coil Side) ................................16
Indoor Blower and Motor.......................................................16
Outdoor Coil, Indoor Coil, and Condensate Drain Pan ........16
Outdoor Fan ............................................................................17
Electrical Controls and Wiring...............................................18
Refrigerant Circuit ..................................................................18
Indoor Airflow ........................................................................18
Metering Devices....................................................................18
Lubrication ..............................................................................18
Liquid Line Strainer................................................................18
High Flow Valves...................................................................19
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
INSTALL FLANGES FOR DUCTWORK CONNEC-
TIONS (50ZH060 ONLY)..................................................6
CONVERTING HORIZONTAL DISCHARGE UNITS TO
DOWNFLOW (VERTICAL) DISCHARGE......................6
Provide for Condensate Disposal.............................................6
Install Electrical Connections...................................................7
HIGH-VOLTAGE CONNECTIONS..................................7
ROUTING POWER LEADS INTO UNIT ........................8
TROUBLESHOOTING ...............................................................22
START-UP CHECKLIST............................................................23
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.
CONNECTING
GROUND
LEAD
TO
UNIT
GROUND ............................................................................8
ROUTING CONTROL POWER WIRES ..........................8
ACCESSORY ELECTRIC HEAT WIRING .....................8
SPECIAL PROCEDURES FOR 208-V OPERATION .....8
PRE-START-UP ............................................................................9
START-UP.....................................................................................9
Check for Refrigerant Leaks ..................................................10
LOCATE AND REPAIR REFRIGERANT LEAKS AND
CHARGE THE UNIT AS FOLLOWS: ...........................10
Start-Up Cooling Section and Make Adjustments ................10
CHECKING COOLING CONTROL OPERATION .......10
COMPRESSOR ROTATION ...........................................10
Refrigerant Charge..................................................................10
NO CHARGE....................................................................10
LOW CHARGE COOLING .............................................10
TO USE THE COOLING CHARGING CHART............10
HEATING MODE CHARGE...........................................11
Indoor Airflow and Airflow Adjustments..............................11
FOR 208/230-V.................................................................12
FOR 460-V MOTORS ......................................................12
Unit Controls...........................................................................12
HIGH-PRESSURE RELIEF VALVE...............................12
LOSS OF CHARGE SWITCH.........................................12
COMPRESSOR OVERLOAD..........................................12
Sequence of Operation............................................................12
FAN OPERATION............................................................12
COOLING..........................................................................14
HEAT PUMP HEATING..................................................14
C00155
Fig. 1—Unit 50ZH
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
Manufacturer reserves the right to discontinue, or change at any time, specifications or designs without notice and without incurring obligations.
Book
Tab
1
6
4
8
PC 101
Catalog No. 535-00080
Printed in U.S.A.
Form 50ZH-5SI
Pg 1
7-03
Replaces: 50ZH-4SI
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REQUIRED CLEARANCE TO COMBUSTIBLE MATL.
INCHES [mm]
TOP OF UNIT.........................................................................................0
DUCT SIDE OF UNIT.............................................................................0
SIDE OPPOSITE DUCTS ......................................................................0
BOTTOM OF UNIT.................................................................................0
NEC. REQUIRED CLEARANCES.
INCHES [mm]
BETWEEN UNITS, POWER ENTRY SIDE....................................42.00 [1066.8]
UNIT AND UNGROUNDED SURFACES, POWER ENTRY SIDE .36.00 [914.0]
UNIT AND BLOCK OR CONCRETE WALLS AND OTHER
GROUNDED SURFACES, POWER ENTRY SIDE.........................42.00 [1066.8]
REQUIRED CLEARANCE FOR OPERATION AND SERVICING
INCHES [mm]
COND. ENSER COIL ACCESS SIDE..............................................30.00 [762.0]
POWER ENTRY SIDE....................................................................30.00 [762.0]
(EXCEPT FOR NEC REQUIREMENTS)
UNIT TOP.......................................................................................48.00 [1219.2]
SIDE OPPOSITE DUCTS ..............................................................30.00 [762.0]
LEGEND
NEC – National Electrical Code
NOTES:
1. Clearances must be maintained to prevent recirculation of air from outdoor-
fan discharge, with the exception of the condenser coil (36.00 in [914.0 mm]. A
removable fence or barricade requires no clearance.
2. Dimensions are in inches. Dimensions in [ ] are in millimeters.
C00156
UNIT WEIGHT
CENTER OF GRAVITY IN. (MM)
UNIT
ELECTRICAL CHARACTERISTICS
lb
kg
X
Y
Z
50ZH024
50ZH030
208/230-1-60
232
106
14.0 (356)
19.0 (483)
12.0 (305)
208/230-1-60,
208/230–3–60
254
116
14.0 (356)
19.0 (483)
12.0 (305)
Fig. 2—Unit Base Dimensions, 50ZH024-030
3
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REQUIRED CLEARANCE TO COMBUSTIBLE MATL.
INCHES [mm]
TOP OF UNIT.........................................................................................0
DUCT SIDE OF UNIT.............................................................................0
SIDE OPPOSITE DUCTS ......................................................................0
BOTTOM OF UNIT.................................................................................0
NEC. REQUIRED CLEARANCES.
INCHES [mm]
BETWEEN UNITS, POWER ENTRY SIDE....................................42.00 [1066.8]
UNIT AND UNGROUNDED SURFACES, POWER ENTRY SIDE .36.00 [914.0]
UNIT AND BLOCK OR CONCRETE WALLS AND OTHER
GROUNDED SURFACES, POWER ENTRY SIDE.........................42.00 [1066.8]
REQUIRED CLEARANCE FOR OPERATION AND SERVICING
INCHES [mm]
COND. ENSER COIL ACCESS SIDE..............................................
POWER ENTRY SIDE....................................................................30.00 [762.0]
(EXCEPT FOR NEC REQUIREMENTS)
30.00 [762.0]
UNIT TOP.......................................................................................48.00 [1219.2]
SIDE OPPOSITE DUCTS ..............................................................30.00 [762.0]
LEGEND
NEC – National Electrical Code
NOTES:
1. Clearances must be maintained to prevent recirculation of air from outdoor-
fan discharge, with the exception of the condenser coil (36.00 in [914.0 mm]. A
removable fence or barricade requires no clearance.
2. Dimensions are in inches. Dimensions in [ ] are in millimeters.
C00003
UNIT WEIGHT
CENTER OF GRAVITY IN. (MM)
UNIT
ELECTRICAL CHARACTERISTICS
lb
kg
X
Y
Z
208/230-1-60, 208/230-3-60,
460–3–60
50ZH036
50ZH042
50ZH048
277
126
14.0 (356)
14.0 (356)
14.0 (356)
19.0 (483)
19.0 (483)
19.0 (483)
15.0 (381)
15.0 (381)
15.0 (381)
208/230-1-60, 208/230-3-60,
460–3–60
295
328
134
149
208/230-1-60, 208/230-3-60,
460–3–60
Fig. 3—Unit Base Dimensions, 50ZH036–048
4
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REQUIRED CLEARANCE TO COMBUSTIBLE MATL.
INCHES [mm]
TOP OF UNIT.........................................................................................0
DUCT SIDE OF UNIT.............................................................................0
SIDE OPPOSITE DUCTS ......................................................................0
BOTTOM OF UNIT.................................................................................0
NEC. REQUIRED CLEARANCES.
INCHES [mm]
BETWEEN UNITS, POWER ENTRY SIDE....................................42.00 [1066.8]
UNIT AND UNGROUNDED SURFACES, POWER ENTRY SIDE .36.00 [914.0]
UNIT AND BLOCK OR CONCRETE WALLS AND OTHER
GROUNDED SURFACES, POWER ENTRY SIDE.........................42.00 [1066.8]
REQUIRED CLEARANCE FOR OPERATION AND SERVICING
INCHES [mm]
COND. ENSER COIL ACCESS SIDE..............................................30.00 [762.0]
POWER ENTRY SIDE....................................................................30.00 [762.0]
(EXCEPT FOR NEC REQUIREMENTS)
UNIT TOP.......................................................................................48.00 [1219.2]
SIDE OPPOSITE DUCTS ..............................................................30.00 [762.0]
LEGEND
NEC – National Electrical Code
NOTES:
1. Clearances must be maintained to prevent recirculation of air from outdoor-
fan discharge, with the exception of the condenser coil (36.00 in [914.0 mm]. A
removable fence or barricade requires no clearance.
2. Dimensions are in inches. Dimensions in [ ] are in millimeters.
C00158
UNIT WEIGHT
CENTER OF GRAVITY IN. (MM)
UNIT
ELECTRICAL CHARACTERISTICS
lb
368
kg
X
Y
Z
50ZH060
208/230-1-60, 208/230-3-60, 460-3-60
167
14.0 (356)
20.0 (508)
16.0 (406)
Fig. 4—Unit Base Dimensions, 50ZH060
5
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INSTALL FLANGES FOR DUCTWORK CONNECTIONS
(50ZH060 ONLY)
The 50ZH060 units are shipped with flanges which must be
field-installed on the unit.
To install unit flanges:
1. Five pieces of flange are shipped on the return-air opening of
the unit. Remove the flanges from the shipping position (See
Fig. 5). Screws are field-supplied.
2. One piece of flange is used as it is shipped (straight). Bend the
other 4 pieces at right angles.
3. Install the straight flange on the right side of the return-air
opening in holes provided. (See Fig. 6). Flanges should stick
out from unit to allow for connection of ductwork.
4. Install 2 hand-formed flanges onto return air opening in holes
provided to form a rectangle around the return air opening.
5. Install remaining 2 hand-formed flanges around discharge air
opening in holes provided.
FIVE PIECES OF DUCT
FLANGE ATTACHED
HERE FOR SHIPMENT
C00005
6. Ductwork can now be attached to flanges.
When designing and installing ductwork, consider the following:
Fig. 5—Shipping Location of Duct Flanges
(Size 060 Only)
When connecting ductwork to units, do not drill deeper than
3/4 inch in shaded area shown in Fig. 7 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 1.
Avoid abrupt duct size increases and reductions. Abrupt change
in duct size adversely affects air performance.
HAND
FORM
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 ectend 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 2.
Heater limit switches may trip at air quantities below those
recommended.
HAND FORM
STRAIGHT PIECE
•
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 Condi-
tioning Contractors National Association (SMACNA) and Air
Conditioning Contractors Association (ACCA) minimum in-
stallation standards for residential heating and air conditioning
systems.
C00006
Fig. 6—Flanges Installed on 50ZH060 Units
CONVERTING HORIZONTAL DISCHARGE UNITS TO
DOWNFLOW (VERTICAL) DISCHARGE
•
Secure all ducts to building structure. Flash, weatherproof, and
vibration-isolate duct openings in wall or roof according to
good construction practices.
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. Elec-
trical shock can cause serious injury or death.
Figure 8 shows a typical duct system with 50ZH unit installed.
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.
6
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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. 2-4 for location of condensate connection.
Failure to follow these precautions could 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 connec-
tions must be in accordance with CSA standard C22.1
Canadian Electrical Code Part 1 and applicable local
codes. Refer to unit wiring diagram.
19.17″
3.92″
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. On
3-phase units, ensure phases are balanced within 2 percent.
Consult local power company for correction of improper
voltage and/or phase imbalance.
C00007
Fig. 7—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 ground-
level 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.
HIGH-VOLTAGE CONNECTIONS
INDOOR
THERMOSTAT
RETURN
AIR
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. 9 and 10.) 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.
FROM
TOP COVER
POWER
SOURCE
POWER AND
LOW-VOLTAGE
ENTRY
DISCONNECT
PER NEC*
(UNIT AND
ELECTRIC
HEATER)
COMPOSITE
RUST-PROOF
BASEPAN
Power Wiring
Control Wiring
CONDENSATE
DRAIN
CONNECTION
Condenser Airflow
Evaporator Airflow
*Separate disconnect per NEC
(National Electrical Code) required
for electric heater when single-
point conection is not used.
C00008
Step 7—Install Electrical Connections
C00008
Table 2—Minimum Airflow for Safe Electric Heater
Operation (CFM)
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 Elec-
trical Code CSA C22.1) and local electrical codes. Failure to
adhere to this warning could result in serious injury or death.
SIZE
024
600
030
750
036
900
042
048
060
1050
1200
1500
Fig. 8—Typical installation
1” (25mm) MIN.
TRAP
OUTLET
2” (50mm) MIN.
C99013
Fig. 9—Condensate Trap (Using Tubing)
The unit must have a separate electrical service with a field-
supplied, 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 3 for electrical data.
7
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Table 1 — Physical Data
UNIT 50ZH
024
030
036
042
048
060
OPERATING WEIGHT (lbs)
COMPRESSOR TYPE
232
254
277
295
328
368
Scroll
R-22
REFRIGERANT Charge (lb)
3.7
5.8
5.9
6.6
9.1
9.7
REFRIGERANT METERING DEVICE
Acutrol™ System
Copper Tubes, Aluminum Plate Fins
OUTDOOR COIL
Rows...Fins/in.
Face Area (sq ft)
1...17
7.9
2...17
6.7
1...17
11.1
2...17
9.3
2...17
11.1
2...17
12.7
Propeller
OUTDOOR-FAN MOTOR CFM
Nominal Rpm
1800
825
1/8
2000
1100
1/4
2600
1100
1/4
2600
1100
1/4
2600
1100
1/4
3200
1100
1/2
Motor Hp
Diameter (in.)
20
20
20
20
20
20
INDOOR COIL
Copper Tubes, Aluminum Plate Fins
Rows...Fins/in.
Face Area (sq ft)
2...15
3.1
3...15
3.1
3...15
4.0
3...15
4.0
4...15
4.4
4...15
4.9
Direct Drive
INDOOR FAN MOTOR
Blower Motor Size (in.)
Nominal Cfm
10 x 8
800
550-1000
3
Low
1/4
10 x 8
1000
550-1000
3
Med
1/4
10 x 9
1200
800-1050
3
10 x 9
1400
800-1050
3
10 x 9
1600
1000-1100
2
10 x 10
2000
950-1100
3
Rpm Range
Number of Speeds
Factory Speed Setting
Motor Hp
Low
1/2
Med
1/2
Low
Low
3/4
1
CONNECTING DUCT SIZES
Supply Air (in.)
Round
14
14
Square
13.9 x 13.9
13.9 x 27.8
Return Air (in.)
FIELD-SUPPLIED RETURN-AIR FILTER†
Throwaway (in.)
24 x 24
24 x 24
24 x 24
24 x 24
24 x 30
24 x 30
* 460-v motors are 2-speed or 3-speed.
†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.
ROUTING CONTROL POWER WIRES
TRAP
OUTLET
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. 11). Connect
thermostat leads and unit power leads as shown in Fig. 13 & 14.
1" min.
Route thermostat wires through grommet providing a drip-loop at
the panel. Connect low-voltage leads to the thermostat as shown in
Fig. 14.
2" min.
The unit transformer supplies 24-v power for complete system
including accessory electrical heater. Transformer is factory wired
for 230-v operation. If supply voltage is 208 v, rewire transformer
primary as described in the Special Procedures for 208-v Opera-
tion section below.
C00009
Fig. 10–PVC Condensate Trap
The field-supplied disconnect may be mounted on the unit over the
high-voltage inlet hole. See Fig. 2-4.
ACCESSORY ELECTRIC HEAT WIRING
Refer to accessory electric heat installation instructions for infor-
mation on installing accessory electric heat. Accessory electric
heat wiring is shown in Fig. 15A & 15B.
Operation of unit on improper line voltage constitutes abuse
and may cause unit damage that could affect warranty.
SPECIAL PROCEDURES FOR 208-V OPERATION
ROUTING POWER LEADS INTO UNIT
Use only copper wire between disconnect and unit. The high-
voltage 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. 11 for location). When the leads are inside the unit,
run leads to the control box (Fig. 12). For single-phase units,
connect leads to the black and yellow wires; for 3-phase units,
connect the leads to the black, yellow, and blue wires (see Fig. 13).
Make sure that the power supply to the unit is switched OFF
and install lockout tag before making any wiring changes.
Electrical shock can cause serious injury or death.
1. Remove wirenut from connection of ORG wire to BLK wire.
Disconnect the ORG transformer-primary lead from the BLK
wire. Save wirenut. See unit wiring label.
2. Remove the wirenut from the terminal on the end of the RED
transformer-primary lead.
CONNECTING GROUND LEAD TO UNIT GROUND
Refer to Fig. 12 and 13. Connect the ground lead to the chassis
using the unit ground lug in the control box.
3. Save the wirenut.
8
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4. Connect the RED lead to the BLK wire from which the ORG
lead was disconnected. Insulate with wirenut from Step 1.
5. Using the wirenut removed from the RED lead, insulate the
loose terminal on the ORG lead.
6. Wrap the wirenuts with electrical tape so that the metal
terminals cannot be seen.
Indoor blower-motor speeds may need to be changed for 208-v
operation. Refer to Indoor Airflow and Airflow Adjustments
section. (See Table of Contents for page number.)
PRE-START-UP
Failure to observe the following warnings could result in
serious injury or death:
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 electri-
cal 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 com-
pressor terminals. Use accepted methods to recover refrig-
erant.
5. Never attempt to repair soldered connection while refrig-
erant 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 fol-
lows:
a. Shut off electrical power to unit and install lockout tag.
UNIT GROUND
GROUND
LEAD
C
O
R
G
Y
BRN
ORN
RED
GRN
SINGLE-PHASE
CONNECTIONS
TO DISCONNECT
PER NEC
L
L
L
BLK
YEL
BLU
3-PHASE
CONNECTIONS
TO DISCONNECT
PER NEC
C00012
Fig. 13—Line Power Connections
YEL
E
WHT
W2
THERMOSTAT
AND SUBBASE
UNIT CONTROL POWER
SPLICE BOX
C99056
Fig. 14—Control Connections
COMPRESSOR ROTATION
Step 1—Check for Refrigerant Leaks
On 3–Phase units it is important to be certain compressor is
rotating in the proper direction. To determine whether or not
compressor is rotating in the proper direction:
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.
1. Connect service gages to suction and discharge pressure
fittings.
2. Repair leak following accepted practices.
2. Energize the compressor.
NOTE: Install a liquid-line filter drier whenever the system has
been opened for repair.
3. The suction pressure should drop and the discharge pressure
should rise, as is normal on any start-up.
Step 2—Start-Up Cooling Section and Make Adjustments
If the suction pressure does not drop and the discharge pressure
does not rise to normal levels:
1. Turn off power to the unit and tag disconnect.
2. Reverse any two of the unit power leads.
3. Turn on power to the unit.
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 when the outdoor temperature
is below 40 F.
The suction and discharge pressure levels should now move to
their normal start-up levels.
Do not rapid-cycle the compressor. Allow 5 minutes between
‘‘on’’ cycles to prevent compressor damage.
NOTE: When the compressor is rotation in the wrong direction,
the unit makes an elevated level of noise and does not provide
cooling.
CHECKING COOLING CONTROL OPERATION
Step 3—Refrigerant Charge
Start and check the unit for proper cooling control operation as
follows:
Refrigerant Charge — Amount of refrigerant charge is listed on
unit nameplate and in Table 1. 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.
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 30 seeconds when FAN
switch is placed in AUTO position.
NO CHARGE
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.
Refer to Carrier Refrigerant Service Techniques. Use standard
evacuating techniques. After evacuating system, weigh in the
specified amount of refrigerant (refer to Table 1).
LOW CHARGE COOLING
Using cooling charging chart (see Fig. 16–21),Vary refrigerant
until conditions of the chart are met. Note that charging chart is
different from those normally used. Charts are based on charging
the units to the correct superheat for the various operating
conditions. An accurate pressure gage and temperature-sensing
device is required. Connect the pressure gauge to the service port
on the suction line. Connect temperature sensing device to the
suction line near the compressor and insulate it so that outdoor
ambient temperature does not affect reading.
3. Place system switch in HEAT position. Observe that compres-
sor, 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).
TO USE THE COOLING CHARGING CHART
This method is to be used in cooling mode only. Take the outdoor
ambient temperature and read the suction pressure gauge. Refer to
10
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C01022
Fig. 15A—Typical Unit Electrical Diagram (208/230–1–60)
charts to determine what the suction temperature should be. If HEATING MODE CHARGE
suction temperature is high, add refrigerant. If suction temperature
is low, carefully recover some of the charge. Recheck the suction
pressure as charge is adjusted.
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.
Example: (See Fig. 16)
Step 4—Indoor Airflow and Airflow Adjustments
Outdoor Temperature —85°F
Suction Pressure—74 psig
Suction Temperature should be—60°F
Note—Suction Temperature may vary +/- 5°F.
NOTE: For cooling operation, the recommended airflow is 350 to
450 cfm per each 12,000 Btuh of rated cooling capacity.
Table 4 shows dry coil air delivery for horizontal discharge units.
Tables 5-7 show pressure drops.
11
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BRN (COMMON)
VIO (STEP 2)
C
W1
W1
WHT ( STEP 1)
CONTACTOR 2
BRN
YEL
BLK
TO
YEL
UNIT POWER
WIRING
YEL
FUSE BLOCK
CONTACTOR 1
AUTO-LIMIT
EL 1
EL 2
EL 3
YEL
YEL
BLK
BLK
F3
F4
F1
F2
BRN
YEL
YEL
BLK
BLK
BLK
YEL
YEL
L2
L1
C00014
Fig. 15B—Accessory Electric Heater Wiring
NOTE: Be sure that all supply- and return-air grilles are open,
free from obstructions, and adjusted properly.
Connect the black lead to the IFR. Insulate the purple lead to avoid
contact with any chassis parts. ON 3–Speed Motors: remove the
fan motor speed leg lead from the indoor (indoor) fan relay (IFR)
and replace with lead for desired blower motor speed.
Disconnect electrical power to the unit and install lockout tag
before changing blower speed. Electrical shock can cause
serious injury or death.
Step 5—Unit Controls
All compressors have the following internal-protection controls.
HIGH-PRESSURE RELIEF VALVE
Airflow can be changed by changing the lead connections of the
blower motor.
This valve opens when the pressure differential between the low
and high side becomes excessive (024 size has temperature relief
only).
Units 50ZH024, 036, 048, and 060 blower motors are factory
wired for low speed operation. Units 50ZH030 and 042 are factory
wired for medium speed operation.
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.
FOR 208/230-V
The motor leads are color-coded as follows:
3-SPEED
2-SPEED
black = high speed
-
COMPRESSOR OVERLOAD
black = high speed
blue = medium speed
red = low speed
This overload interrupts power to the compressor when either the
current or internal temperature become excessive, and automati-
cally 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.
red = low speed
To change the speed of the indoor fan motor (IFM), remove the fan
motor speed leg lead from the indoor fan relay (IFR) with units
024, 030, 042, 048 & 060 or the time delay relay (TDR) on 036
size and replace with lead for desired blower motor speed. Insulate
the removed lead to avoid contact with chassis parts.
Step 6—Sequence of Operation
FOR 460-V MOTORS
FAN OPERATION
The motor leads are color coded as follows:
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.
3-SPEED (060 ONLY)
black = high speed
-
2-SPEED
black = to purple
yellow = line
orange = medium speed
blue = low speed
purple = to black
red = line
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.
To change the speed of the indoor fan motor (IFM) from low speed
to high speed, remove the red lead from the indoor-fan relay (IFR).
ON 2–Speed Motors: Insulate the red lead to avoid contact with
any chassis parts. Separate the black lead from the purple lead.
12
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→
Table 3—Electrical Data—50ZH
VOLTAGE
RANGE
UNIT 50ZH
SIZE
(–SERIES, IF
USED)
COMPRESSOR
ELECTRIC HEAT
SINGLE POINT POWER SUPPLY
OFM
FLA
IFM
FLA
V-PH-HZ
FUSE OR
CKT BKR
MIN
MAX
RLA
11.4
LRA
56.0
Nominal KW*
FLA
MCA
MOCP
-/-
-/-
17.6/17.6
40.4/43.6
51.2/56.7
62.7/69.7
25/25
45/45
60/60
-
-
-
-
3.8/5.0
5.6/7.5
7.5/10.0
18.3/20.8
26.9/31.3
36.1/41.7
024–311
024–321
208/230–1–60
208/230–1–60
187
254
0.9
0.9
2.4
2.4
70/70
-/-
-/-
18.4/18.4
41.3/44.4
52.1/57.6
63.6/70.6
25/25
45/45
60/60
—
—
—
—
3.8/5.0
5.6/7.5
7.5/10.0
18.3/20.8
26.9/31.3
36.1/41.7
187
187
187
187
254
254
254
254
12.1
14.4
10.0
17.7
54.0
73.0
63.0
93.0
70/80
-/-
-/-
21.9/21.9
44.8/47.9
55.5/61.0
67.0/74.0
89.8/100.0
30/30
45/50
60/–
—
—
—
–/70
70/80
90/110
3.8/5.0
5.6/7.5
7.5/10.0
11.3/15.0
18.3/20.8
26.9/31.3
36.1/41.7
54.2/62.5
208/230–1–60
208/230–3–6
208/230–1–60
1.5
1.5
1.5
2.4
5.8
2.8
–
030
-/-
-/-
16.8
20
—
—
—
3.8/5.0
7.5/10.0
11.3/15.0
10.4/12.0
20.8/24.1
31.3/36.1
29.9/31.8
42.8/46.9
56.1/61.9
35/35
45/50
60/–
–/70
-/-
-/-
26.4/26.4
49.3/52.4
60.1/65.6
74.6/78.6
94.3/104.6
35/35
50/60
—
—
—
—
—
70/70
80/80
100/110
3.8/5.0
5.6/7.5
7.5/10.0
11.3/15.0
18.1/20.8
26.9/31.3
36.1/41.7
54.2/62.5
-/-
-/-
18.6/18.6
31.7/33.6
44.6/48.7
57.8/63.7
25/25
35/35
45/50
60/-
—
—
—
036
3.8/5.0
7.5/10.0
11.3/15.0
10.4/12.0
20.8/24.1
31.3/36.1
208/230–3–60
460–3–60
187
414
254
508
11.4
5.7
77.0
39.0
1.5
0.8
2.8
2.0
–/70
—
5
10
15
—
6.0
12.0
18.0
9.9
15
20
25
35
—
—
—
—
17.4
24.9
32.4
-/-
-/-
31.8/31.8
54.7/57.8
65.4/70.9
76.9/83.9
99.7/109.9
121.9/135.9
40/40
60/60
—
—
—
—
—
70/80
80/90
100/110
125/150
3.8/5.0
5.6/7.5
7.5/10.0
11.3/15.0
15/20
18.3/20.8
26.9/31.3
36.1/41.7
54.3/62.5
72.1/83.3
208/230–1–60
187
254
22.0
103.0
1.5
2.8
—
-/-
-/-
21.7/21.7
34.8/36.7
47.7/51.8
60.9/66.8
73.4/81.6
30/30
35/40
50/50
—
—
—
—
70/70
80/90
3.8/5.0
7.5/10.0
11.3/15.0
15/20
10.5/12.0
20.8/24.1
31.4/36.1
41.4/47.9
042
048
060
208/230–3–60
460–3–60
187
414
254
508
13.9
6.8
88.0
44.0
1.5
0.8
2.8
2.0
—
—
5
10
15
20
—
6.0
12.0
18.0
24.1
11.3
18.8
26.3
33.8
41.4
15
20
30
35
45
—
—
—
—
—
-/-
-/-
33.0/33.0
55.8/59.0
66.6/72.1
78.1/85.1
100.8/111.1
123.1/137.1
40/40
60/60
—
—
—
—
—
70/80
80/90
110/125
125/150
3.8/5.0
5.6/7.5
7.5/10.0
11.3/15.0
15/20
18.3/20.8
26.9/31.3
36.1/41.7
54.2/62.5
72.2/83.3
208/230–1–60
187
254
21.8
124.0
1.5
4.2
—
-/-
-/-
21.7/21.70
34.8/36.7
47.7/51.8
61.0/66.8
73.5/81.6
25/25
35/40
50/60
—
—
—
—
70/70
80/90
3.8/5.0
7.5/10.0
11.3/15.0
15/20
10.5/12.0
20.8/24.1
31.4/36.1
41.4/47.9
208/230–3–60
460–3–60
187
414
254
508
12.8
6.4
93.0
46.5
1.5
0.8
4.2
4.2
—
—
5
10
15
20
—
6.0
12.0
18.0
24.1
10.9
18.4
25.9
33.4
40.8
15
20
30
35
45
—
—
—
—
—
—
3.8/5
5.6/7.5
7.5/10
11.3/15
15.0/20
—
43.9/43.9
66.8/69.9
77.6/83.1
89.1/96.1
111.8/122.1
134.1/148.1
60/60
—
—
—
—
—
70/70
80/90
90/100
125/125
150/150
18.3/20.8
26.9/31.3
36.1/41.7
54.3/62.5
72.1/83.3
230–1–60
187
254
27.7
170.0
3.1
6.2
—
-/-
3.8/5.0
7.5/10.0
11.3/15.0
14.9/19.9
-/-
29.2/29.2
42.3/44.2
55.2/59.3
68.4/74.3
80.9/89.1
35/35
45/45
60/60
—
—
—
—
70/80
90/90
10.5/12.0
20.8/24.1
31.4/36.1
41.4/47.9
208/230–3–60
460–3–60
187
414
254
508
15.9
8.0
124.0
59.6
3.1
1.5
6.2
3.2
—
—
5
10
15
19.9
—
6.0
12.0
18 .0
23.9
14.7
22.2
29.7
37.2
44.6
20
25
30
40
45
—
—
—
—
—
(See legend following Electrical Data charts)
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13
EXAMPLE: Supply voltage is 460-3-60.
AB = 452 v
BC = 464 v
AC = 455 v
LEGEND
FLA
LRA
MCA
— Full Load Amps
— Locked Rotor Amps
— Minimum Circuit Amps
452 + 464 + 455
®
Average Voltage =
3
1371
3
MOCP — Maximum Overcurrent Protection
RLA
CKT BKR
— Rated Load Amps
=
—
Circuit Breaker
= 457
NOTES:
Determine maximum deviation from average voltage.
(AB) 457 452 = 5 v
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. Canadian units may be
fuse or circuit breaker.
(BC) 464 457 = 7 v
(AC) 457 455 = 2 v
Maximum deviation is 7 v.
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.
Determine percent of voltage imbalance.
7
% Voltage Imbalance = 100 x
3. Unbalanced 3-Phase Supply Voltage
457
Never operate a motor where a phase imbalance in supply volt-
age is greater than 2%. Use the following formula to determine
the percentage of voltage imbalance.
= 1.53%
This amount of phase imbalance is satisfactory as it is below the
maximum allowable 2%.
% Voltage imbalance
max voltage deviation from average voltage
= 100 x
IMPORTANT: If the supply voltage phase imbalance is
more than 2%, contact your local electric utility company
immediately.
average voltage
C99024
758 110
758 110
OUTDOOR TEMP
OF
OC
683 100
621 90
552 80
683 100
OUTDOOR TEMP
115 46
OF
OC
115 46
105 41
95 35
85 29
75 24
65 18
55 13
621 90
552 80
105 41
95 35
85 29
75 24
65 18
483 70
414 60
483 70
414 60
45
7
55 13
45
7
345 50
276 40
345 50
276 40
207 30
207 30
30
-1
40
50
60
70
80
90
32
30
-1
40
50
60
70
80
90
32
O
O
SUCTION LINE TEMPERATURE ( F)
SUCTION LINE TEMPERATURE ( F)
4
10 16 21 27
4
10 16 21 27
O
O
SUCTION LINE TEMPERATURE ( C)
SUCTION LINE TEMPERATURE ( C)
Fig. 17—Cooling Charging Chart, 50ZH030C00163
C00162
Fig. 16—Cooling Charging Chart, 50ZH024 Units
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.
When the need for cooling has been satisfied, the OFM, compres-
sor, and IFM (FAN on AUTO) are deenergized. If the unit is
equipped with a 30-second delay (036 size only), the indoor fan
will remain energized for 30 seconds after the compressor is
deenergized. The reversing valve solenoid remains energized.
COOLING
With the thermostat subbase in the cooling position, the thermostat
makes circuit R-O. This energizes the reversing valve solenoid
(RVS) and places the unit in standby condition for cooling.
HEAT PUMP HEATING
On a call for heat, thermostat makes circuits R-Y and R-G. When
compressor time delay (5-minute ± 2 minutes) is completed, a
circuit is made to C, starting COMP and OFM. Circuit R-G also
energizes IFR and starts IFM after 1-second delay.
NOTE: The defrost control board has a 5 minute compressor
anti-short cycle time delay built in between compressor starts.
On a call for cooling, the compressor contactor (C) and the IFR are
energized through the Y and G terminals of the thermostat.
Energizing the compressor contactor supplies power to the com-
pressor and the outdoor (condenser) fan motor (OFM). Energizing
the IFR provides power to the IFM.
Should room temperature continue to fall, circuit R-W is made
through second-stage thermostat bulb. If optional electric heat
package is used, a relay is energized, bringing on first bank of
14
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758 110
758 110
683 100
621 90
552 80
683 100
621 90
552 80
OUTDOOR TEMP
OF OC
OUTDOOR TEMP
OF OC
115 46
105 41
115 46
105 41
95 35
85 29
95 35
85 29
75 24
65 18
75 24
65 18
55 13
483 70
414 60
483 70
414 60
55 13
45
7
45
7
345 50
276 40
345 50
276 40
207 30
207 30
30
-1
40
50
60
70
80
90
32
30
-1
40
50
60
70
80
90
32
O
O
SUCTION LINE TEMPERATURE ( F)
SUCTION LINE TEMPERATURE ( F)
4
10 16 21 27
4
10 16 21 27
O
O
SUCTION LINE TEMPERATURE ( C)
SUCTION LINE TEMPERATURE ( C)
C00164
C00166
Fig. 18—Cooling Charging Chart, 50ZH036 Units
Fig. 20—Cooling Charging Chart, 50ZH048 Units
758 110
758 110
OUTDOORTEMP
OF
OC
683 100
683 100
621 90
552 80
OUTDOOR TEMP
OF
OC
115 46
105 41
115 46
621 90
552 80
105 41
95 35
95 35
85 29
75 24
85 29
75 24
65 18
55 13
65 18
55 13
483 70
414 60
483 70
414 60
45
7
45
7
345 50
276 40
345 50
276 40
207 30
207 30
30
-1
40
50
60
70
80
90
32
30
-1
40
50
60
70
80
90
32
O
O
SUCTION LINE TEMPERATURE ( F)
SUCTION LINE TEMPERATURE ( F)
4
10 16 21 27
4
10 16 21 27
O
O
SUCTION LINE TEMPERATURE ( C)
SUCTION LINE TEMPERATURE ( C)
C00165
C00167
Fig. 19—Cooling Charging Chart, 50ZH042 Units
Fig. 21—Cooling Charging Chart, 50ZH060 Units
supplemental electric heat. When thermostat is satisfied, contacts
open, deenergizing contactor and relay; motors and heaters deen-
ergize. The IFM may be controlled by a time-delay relay that keeps
the fan on for 30 seconds.
ELECTRIC RESISTANCE HEATING
If accessory electric heaters are installed, on a call for “Emergency
Heat” the thermostat energizes W which energises 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 deenergized.
DEFROST
Defrost board (DB) is a time and temperature control, which
includes a field-selectable time period between checks for defrost
(30, 50 and 90 minutes). The time period is factory-set at 30
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.
MAINTENANCE
To ensure continuing high performance, and to reduce the possi-
bility of premature equipment failure, periodic maintenance must
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.
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.
15
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NOTE TO EQUIPMENT OWNER: Consult your local dealer
about the availability of a maintenance contract.
Disconnect and tag electrical power to the unit before
removing top. Failure to adhere to this warning could cause
serious injury or death.
The ability to properly perform maintenance on this equip-
ment 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. FAILURE
TO HEED THIS WARNING COULD RESULT IN SERI-
OUS INJURY, DEATH OR DAMAGE TO THIS EQUIP-
MENT.
Only qualified service personnel should perform maintenance and
service procedures that require unit top removal.
Refer to the following top removal procedures:
1. Remove 7 screws on unit top cover surface. (Save all screws.)
2. Remove 2 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.
The minimum maintenance requirements for this equipment are as
follows:
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.
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.
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.
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 neces-
sary.
Disconnect and tag electrical power to the unit before
cleaning the blower wheel. Failure to adhere to this warning
could cause serious injury or death.
5. Check the drain channel in the top cover periodically for
blockage (leaves, insects). Clean as needed.
To clean the blower wheel:
1. Access the blower assembly as follows:
a. Remove top access panel.
Failure to follow these warnings could result in serious injury
or death:
b. Remove 3 screws that hold blower orifice ring to blower
housing. Save screws.
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.
c. Loosen setscrew(s) which secure wheel to motor shaft.
2. Remove and clean blower wheel as follows:
a. Lift wheel from housing. When handling and/or cleaning
blower wheel, be sure not to disturb balance weights (clips)
on blower wheel vanes.
3. Never place anything combustible either on, or in contact
with, the unit.
b. Remove caked-on dirt from wheel and housing with a
brush. Remove lint and/or dirt accumulations from wheel
and housing with vacuum cleaner, using a soft brush
attachment. Remove grease and oil with a mild solvent.
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 1 for recommended filter sizes
c. Reassemble blower into housing. Place upper orifice ring
on blower to judge location of the blower wheel. Blower
wheel should be approximately 0.2-in. below bottom of
orifice ring when centered correctly. Be sure setscrews are
tightened on motor and are not on round part of shaft.
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.
d. Set upper orifice ring in place with 3 screws removed in
step 1.
Step 2—Unit Top Removal (Outdoor-Coil Side)
e. Replace top access panel.
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.
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 above.
Remove all obstructions (including weeds and shrubs) that inter-
fere 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
16
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Table 4—Dry Coil Air Delivery* Horizontal Discharge
(Deduct 10 percent for 208 Volt Operation)
230 AND 460 VOLT
External Static Pressure (in. wg)
Unit
024
Motor Speed
Low
Watts/CFM
0.1
288
875
390
1131
528
1391
288
875
390
1131
528
1891
450
1231
470
1302
660
1700
478
1303
481
1310
-
0.2
285
820
383
1090
520
1338
285
820
383
1090
520
1338
435
1218
450
1264
635
1660
458
1270
468
1280
798
1736
-
0.3
282
0.4
279
734
369
978
495
1200
279
734
369
978
495
1200
400
1120
410
1163
575
1450
411
1179
438
1181
647
1618
760
1841
-
0.5
274
668
360
917
480
1115
274
668
360
917
480
1115
380
1008
388
1081
540
1297
378
1126
404
1110
618
1510
730
1757
-
0.6
268
582
350
830
460
1018
268
582
350
830
460
1018
335
950
359
940
505
1190
350
1022
370
1022
578
1421
688
1682
-
0.7
261
478
340
721
450
920
261
478
340
721
450
920
326
863
338
873
485
1095
327
911
338
943
540
1309
650
1564
-
0.8
-
0.9
Watts
Cfm
-
802
-
-
Watts
Cfm
378
-
-
Med
1038
510
-
-
Watts
Cfm
-
-
High
Low
1285
282
-
-
Watts
Cfm
-
-
802
-
-
Watts
Cfm
378
-
-
030
036
Med
1038
510
-
-
Watts
Cfm
-
-
High
Low
1285
420
-
-
Watts
Cfm
311
751
321
783
460
999
317
816
320
811
500
1187
600
1429
-
-
1204
445
-
Watts
Cfm
-
-
Med
1205
610
Watts
Cfm
-
High
Low
1581
440
-
Watts
Cfm
-
1224
450
-
Watts
Cfm
-
042 †
048 †
060 †
Med
1241
678
-
Watts
Cfm
460
1060
570
1333
-
High
Low
-
1688
801
Watts
Cfm
-
-
-
1898
-
Watts
Cfm
-
-
Med
-
-
-
-
-
-
-
-
-
Watts
Cfm
-
-
870
842
1903
790
1762
950
1960
958
2122
818
1799
735
1703
890
1901
896
2052
782
1718
680
1640
835
1855
840
1926
696
1625
580
1415
790
1752
800
1791
632
1446
480
1159
650
1468
691
1588
628
1365
422
950
580
1121
575
1202
High
Low
-
-
2000
810
Watts
Cfm
890
1834
1040
2230
1073
2230
850
1820
1018
2102
1038
2202
1791
1000
2025
1001
2160
Watts
Cfm
Med
Watts
Cfm
High
† 460-v motors are 2-speed.
Air delivery values are based on operating voltage of 230-v. or 460-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.
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-
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.
Step 5—Outdoor Fan
Keep the Outdoor fan free from all obstructions to ensure
proper cooling operation. Never place articles on top of the
unit. Damage to unit may result.
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.
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. 21 or 22.
5. Tighten setscrews.
6. Replace outdoor-fan assembly.
17
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Table 5—Wet Coil Pressure Drop
3.125 in.
UNIT SIZE
AIRFLOW
(CFM)
PRESSURE DROP
50ZH
(IN. WG)
0.02
0.05
0.06
0.07
0.06
0.06
0.08
0.07
0.09
0.11
0.12
0.04
0.06
0.08
0.09
0.07
0.08
0.09
0.07
0.08
0.09
0.10
600
700
024
800
C00021
900
Fig. 21—Outdoor-Fan Adjustment (024–048 Size)
900
030
036
1000
1200
1000
1200
1400
1600
1000
1200
1400
1600
1400
1600
1800
1700
1800
2100
2300
042
048
060
0.708in.
C02017
Fig. 22—Outdoor-Fan Adjustment (060 Size)
operating cycle, or if a suspected malfunction has occurred, check
each electrical component with the proper electrical instrumenta-
tion. 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
Table 6—Filter Pressure Drop (in. wg)
Inspect all refrigerant tubing connections and the unit base for oil
accumulations annually. Detecting oil generally indicates a refrig-
erant leak.
UNIT
SIZE
50ZH
FILTER
CFM
SIZE
(IN.)
500 600 700 800 900 1000 1100 1200 1300 1400
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.)
024-042 24 x 24 0.06 0.07 0.08 0.08 0.09 0.09 0.09 0.10 0.11 0.12
048, 060 24 x 30
-
-
-
-
-
-
-
-
0.08 0.09
UNIT
SIZE
50ZH
FILTER
SIZE
(IN.)
CFM
If no refrigerant leaks are found and low cooling performance is
suspected, refer to Refrigerant Charge. (See Table of Contents for
page number.)
1500 1600 1700 1800 1900 2000 2100 2200 2300
024-042 24 x 24 0.14 0.15
-
-
-
-
-
-
-
048,060 24 x 30 0.10 0.11 0.12 0.13 0.14 0.15 0.16 0.17 0.18
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.
Table 7—Accessory Electric Heat Pressure Drop
(in. wg)
CFM
HEATER KW
600 800 1000 1200 1400 1600 1800 2000 2200
5-20
0.06 0.08 0.10 0.13 0.15 0.18 0.20 0.23 0.25
Step 9—Metering Devices
Step 6—Electrical Controls and Wiring
Refrigerant metering devices are fixed orifices and are located in
the inlet header to the indoor and outdoor coils.
Inspect and check the electrical controls and wiring annually. Be
sure to turn off the electrical power to the unit and install lockout
tag.
Check valves are also located in the liquid lines near the strainers.
The check valves are the smaller of the two components.
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.
Step 10—Lubrication
COMPRESSOR—The compressor is charged with the correct
amount of oil at the factory.
FAN MOTOR BEARINGS—Fan motor bearings are perma-
nently lubricated. No further lubrication of outdoor or indoor fan
motors is required.
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.
Step 11—Liquid Line Strainer
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
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.
18
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OUTDOOR COIL
INDOOR COIL
B
A
LCS
D
Check Valves
STRAINER
A
B
C
D
Open
C
Closed
Open
Closed
LEGEND
LCS
Loss of Charge Switch
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 the cooling 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.
3. Each circuit evaporates the refrigerant and the circuits are com-
bined in the outdoor 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.
C95045
Fig. 23–Typical Heat Pump Operation, Heating Mode
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 can not be
accessed for service in the field. Ensure the plastic caps are in
place and tight or the possibility of refrigerant leakage could occur.
19
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OUTDOOR COIL
INDOOR COIL
B
A
LCS
D
Check Valves
STRAINER
A
B
C
D
Closed
Open
C
Closed
Open
LEGEND
LCS
Loss of Charge Switch
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 con-
densed and subcooled through converging circuits. Refrigerant leaves
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.
3. Each circuit evaporates the refrigerant and the circuits are com-
bined 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
Fig. 24–Typical Heat Pump Operation, Cooling Mode
20
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Balance Point Worksheet
80000
70000
60000
50000
40000
30000
20000
10000
0
024
030
036
042
048
060
-10
0
10
20
30
40
50
60
Outdoor Air Temp (Deg F)
C01038
Fig. 25–50ZH Balance Point Chart
21
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Table 8—Troubleshooting—Cooling and Heating
SYMPTOM
CAUSE
REMEDY
Power Failure
Loss of Charge
Switch open
Call power company
Evaluate unit for possible refrigerant leak
Replace fuse or reset circuit breaker
Replace component
Fuse blown or circuit breaker tripped
Defective thermostat, contractor, transformer, or
control relay
Compressor and outdoor fan will not start.
Insufficient line voltage
Incorrect or faulty wiring
Determine cause and correct
Check wiring diagram and rewire correctly
Lower thermostat setting below room tempera-
ture
Thermostat setting too high
Faulty wiring or loose connections in compressor
circuit
Check wiring and repair or replace
Compressor motor burned out, seized, or internal
overload open
Determine cause
Replace compressor
Compressor will not start but outdoor fan
runs.
Defective run/start capacitor, overload, start relay
Determine cause and replace
Replace fuse or reset circuit breaker
Determine cause
One leg of 3-phase power dead
Low input voltage
(20 percent low)
Determine cause and correct
Recover refrigerant, evacuate system, and re-
charge to capacities shown on nameplate
Refrigerant overcharge or undercharge
Loss of Charge
Switch open
Evaluate unit for possible refrigerant leak
Defective compressor
Insufficient line voltage
Replace and determine cause
Determine cause and correct
Determine cause and correct
Compressor cycles
(other than normally satisfying thermostat).
Blocked outdoor coil (cooling)
Defective run/start capacitor, overload or start
relay
Determine cause and replace
Defective thermostat
Faulty outdoor-fan motor or capacitor
Restriction in refrigerant system
Dirty air filter
Replace thermostat
Replace
Locate restriction and remove
Replace filter
Unit undersized for load
Thermostat set too low
Decrease load or increase unit size
Reset thermostat
Low refrigerant charge
Locate leak, repair, and recharge
Replace compressor
Leaking valves in compressor
Compressor operates continuously.
Frosted outdoor coil with incorrect
defrost operation (heating)
Check defrost time settings. Reset as necessary.
Check defrost temperature switch. Replace as necessary.
Recover refrigerant, evacuate system, and re-
charge
Air in refrigerant system
outdoor coil dirty or restricted
Dirty air filter
Clean coil or remove restriction
Replace filter
Dirty outdoor coil
Clean coil
Refrigerant overcharged
Recover excess refrigerant
Excessive head pressure.
Recover refrigerant, evacuate system, and re-
charge
Air in refrigerant system
Outdoor or indoor air restricted
or air is recirculating
Determine cause and correct
Low refrigerant charge
Compressor valves leaking
Restriction in liquid tube
High heat load
Check for leaks, repair and recharge
Replace compressor
Head pressure too low.
Remove restriction
Check for source and eliminate
Replace compressor
Excessive suction pressure.
Compressor valves leaking
Refrigerant overcharged
Dirty air filter (cooling)
Recover excess refrigerant
Replace Filter
Low refrigerant charge
Check for leaks, repair, and recharge
Remove source of restriction
Metering device or low side restricted
Increase air quantity
Check filter- replace if necessary
Suction pressure too low.
Insufficient indoor airflow (cooling)
Temperature too low in conditioned area (cooling)
Outdoor ambient below 40°F (cooling)
Field-installed filter-drier restricted
Reset thermostat
Install low-ambient kit
Replace
Compressor runs but
outdoor fan does not.
Normally closed contacts on
defrost board open
Check condition of relay on board.
Replace board if necessary.
22
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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
____ Verify that 3-phase scroll compressor is rotating in correct direction.
*Measured at suction inlet to compressor
†Measured at liquid line leaving outdoor coil
23
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Copyright 2003 CARRIER Corp. • 7310 W. Morris St. • Indianapolis, IN 46231
50zh5si
Manufacturer reserves the right to discontinue, or change at any time, specifications or designs without notice and without incurring obligations.
Book
Tab
1
6
4
8
PC 101
Catalog No. 535-00080
Printed in U.S.A.
Form 50ZH-5SI
Pg 24
7-03
Replaces: 50ZH-4SI
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