Carrier Air Conditioner 50ZH024 060 User Manual

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  
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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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