Carrier 50ZH024 User manual

turn to the expe_
Installation Instructions
NOTE: Read the entire instruction manual before starting the
installation.
TABLE OF CONTENTS
PAGE
SAFETY CONSIDERATIONS ......................... 1
INTRODUCTION ................................... 5
RECEIVING AND INSTALLATION .................. 5-9
Check Equipment .................................. 5
Identify Unit .................................... 5
Inspect Shipment ................................. 5
Provide Unit Support ............................... 5
Slab Mount ..................................... 5
Ground Mount .................................. 5
Provide Clearances ................................. 5
Place Unit ........................................ 5
Select and Install Ductwork ........................... 5
Install Flanges for Ductwork Connections (50ZH060 only) 5
Converting Horizontal Discharge Units to Downflow (Vertical)
Discharge ...................................... 6
Provide for Condensate Disposal .................... 6-8
Install Electrical Connections ......................... 8
High Voltage Connections .......................... 8
Routing Power Leads into Unit ...................... 8
Connecting Ground Lead to Unit Ground .............. 8
Routing Control Power Wires ....................... 9
Special Procedures for 208-V Operation ............... 9
PRE-START-UP .................................... 9
START-UP ..................................... 11-13
Check for Refrigerant Leaks ......................... 11
Start-Up Cooling Section and Marke Adjustments ........ 11
Check Cooling Control Operation ................... 11
Compressor Rotation ............................. 11
Refrigerant Charge ................................ 11
No Charge ..................................... 11
Low Charge Cooling ............................. 11
To Use Cooling Charging Charts .................... 11
Heating Mode Charge ............................ 11
Indoor Airflow and Airflow Adjustments ............... 11
Unit Controls .................................... 13
High-Pressure Relief Valve ........................ 13
Loss of Charge Switch ............................ 13
Compressor Overload ............................ 13
Sequence of Operation ............................. 13
Fan Operation .................................. 13
Cooling ....................................... 13
Heat Pump Heating .............................. 13
Defrost ....................................... 13
MAINTENANCE ................................ 14-18
Air Filter ........................................ 14
Unit Top Removal (Condenser Coil Side) ............... 14
Evaporator Blower and Motor ........................ 14
Condenser Coil, Evaporator Coil, and Condensate Drain Pan 15
Condenser Fan ................................... 15
Electrical Controls and Wiring ....................... 15
C00001
Fig. 1 - 50ZH
Refrigerant Circuit ................................. 17
Evaporator Airflow ................................ 17
Metering Devices ................................. 17
Lubrication ...................................... 17
Liquid Line Strainer ............................... 17
High Flow Valves ................................. 17
TROUBLESHOOTING .............................. 17
START-UP CHECKLIST ............................ 17
NOTE: TO INSTALLER - Before the installation, READ
THESE INSTRUCTIONS CAREFULLY AND COMPLETELY.
Also, make sure the User's Manual is left with the unit after
installation.
SAFETY CONSIDERATIONS
Improper installation adjustment, alteration, service, maintenance,
or use can cause explosion, fire, electrical shock, or other
conditions which may cause death, personal injury, or property
damage. Consult a qualified installer, service agency, or your
distributor or branch for information or assistance. The qualified
installer or agency must use factory-authorized kits or accessories
when modifying this product Refer to the individual instructions
packaged with the kits or accessories when installing.
Follow all safety codes. Wear safety glasses, protective clothing,
and work gloves. Use quenching cloth for brazing operations.
Have a fire extinguisher available. Read these instructions
thoroughly and follow all warnings or cautions included in
literature and attached to the unit. Consult local building codes, the
current editions of the National Electrical Code (NEC) NFPA 70.
In Canada refer to the current editions of the Canadian Electrical
Code CSA C22.1.
Recognize safety information. This is the safety-alert symbol Z_
When you see this symbol on the unit and in instructions or
manuals, be alert to the potential for personal iniury. Understand
these signal words; DANGER, WARNING, and CAUTION. These
words are used with the safety-alert symbol. DANGER identifies
the most serious hazards which will result in severe personal iniury
or death. WARNING signifies hazards which could result in
personal iniury or death. CAUTION is used to identify unsafe
practices which may result in minor personal iniury or product and
property damage. NOTE is used to highlight suggestions which
will result in enhanced installation, reliability, or operation.

[24
CON)
COIL_
!1,57 _ !6,06
[294,0] [408,0]
REAR VIEW
\\_ !4,0 DIA,
[356,0]
DUCTOPENINGS
EVAP CO I L_\\ \
f
50,98
[!295,0]
BOTTOMOF UNIT
\\ \\\ \\ x\
II
REQUIRED CLEARANCE TO COMBUSTIBLE M_L 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 [9! 4.0]
UNIT AND BLOCK OR CONCRETE WALLS AND OTHER
GROUNDED SURFACES, POWER ENTRY SIDE ......................... 42,00 [!066.8]
REQUIRED CLEARANCE FOR OPERATION AND SERVICING
INCHES [mm]
CONDENSER 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
NED 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 ram], A
removable fence or barricade requires no clearance.
2. Dimensions are in inches, Dimensions in [ ] are in millimeters,
[812,5]
BOTTObOf UNIT
BLO_S_ER, (IONFROL BOX AND EVAP COIL
ACCESS PANEL
n o rh o
LEFT SIDE VIEW FRONT VIEW
1.20
[30.6]
1.0540 I.D. x .50 DEE_
[26.772] x 12.7 DEEP RIGHT SIDE VIEW
Fig. 2 - Base Unit Dimensions, 50ZH024-036
2.50
"[63.51
C00156
UNIT
50ZH024
50ZH030
ELECTRICAL CHARACTERISTICS
208/230 - 1-60
208/230 - 1-60
UNIT WEIGHT
Ib kg
218 99
245 111
CENTER OF GRAVITY IN, (MM)
XYZ
14.0 19.0 12.0
(356) (483) (305)
14.0 19.0 12.0
(356) (483) (305)

1!.57 16.06
[294.0] [408.0]
9.75
REAR VIEW
o
\, 14.0 DIA.
[356.01
DUCT OPENINGS
REQUIRED CLEARANCE TO COMBUSTIBLE M,,,,,,,,,,,,,,,,,,_¢L
INCHES [mini
TOP OF UNIT ......................................................................................... 0
DUCT SIDE OF UNIT ............................................................................. 0
SIDE OPPOSITE DUCTS ...................................................................... 0
BOTTOM OF UNIT ................................................................................. 0
NEe, REQUIRED CLEARANCES,
_NCHES [mini
BETWEEN UNITS POWER ENTRY SIDE .................................... 42.00 [1086.8]
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 [1068.8]
REQUIRED CLEARANCE FOR OPERATION AND SERVICING
INCHES [mini
CONDENSER COIL ACCESS SIDE .............................................. 30.00 [762.0]
POWER ENTRY SDE .................................................................... 30.00 [782.0]
(EXCEPT FOR NEC REQUIREMENTS)
UNIT TOP ....................................................................................... 48,00 [1219.2]
SIDE OPPOSITE DUCTS .............................................................. 30.00 [782.0]
LEGEND
NEC National Electrical Code
NOTES:
1. Clearances must be maintained to prevent recircu}ation of air from outdoor-
fan discharge with the exception of the condenser coi_ (38.00 in [914.0 mini. A
removable fence or barricade requires no clearance.
2. Dimensions are in inches. Dimensions in [ ] are in millimeters.
CONDENSER_
COIL
50.98
[! 295.0]
50TTOMOK UNIT
EVAPORATOR
COIL _\ \\
I \
\\
9
[8!2.5]
BOTTOMOF UNIF
BLOWER, CONTROL BOX AND
EVAPORATOR COIL ACCESS PANEL
LEFT SiDE VIEW
2.72 2! .6!
[549.0]
....,, 1.75DIA.
[44.5]
1.2_
[30.6] /
FRONTVIEW 1.0540 I.D. x ,50 DEEP
[26.772 x 12.7] RIGHT
Fig. 3 -Base []nit Dimensions, 50ZH036-048
! 9.61 2.50
[498. !] [63.5]
SIDEVIEW C00003
UNIT
50ZH036
50ZH042
50ZH048
ELECTRICAL CHARACTERISTICS
208/230 - 1-60
208/230 - 1-60
208/230 - 1-60
UNIT WEIGHT
Ib kg
270 122
293 133
323 147
CENTER OI= GRAVITY IN, (MM)
XYZ
14.0 19.0 15.0
(356) (483) (381)
14.0 19.0 15.0
(356) (483) (381)
14.0 19.0 15.0
(356) (483) (381)

DIMENSIONSIN[]AREINMM
CON[}
4.63
[117.6]
}OIL \ \\
13.89
[352.7]
2.11
f
[!38.3] ;
_.........................................[.............................................:_..........................................................................................................................................................................................;.............................................:.....................................
I 3.50
REAR ViEW [88.9]
27.80
[706.0]
LEFT SDE VEW
50.98
[1295.0]
BOTT04 OF U/IT
E_AP (}01Lm\\\\ \
\, y-f
\
1
. i..... ! ,!
',i_'_! ..... qd l,i
. .
REQUIRED CLEARANCE TO CO_,IBUST[BLE M,_I'L. INCHES [ram]
TOP OF UNIT .................................................................................... 0
DUCT SIDE OF UNIT ............................................................................. 0
SiDE OPPOSITE DUCTS ...................................................................... 0
BOTTOM OF UNIT ................................................................................. 0
NEC. REQUIRED CLEARANCES. INCHES [ram]
BETWEEN UNITS, POWER ENTRY SIDE ........................... 42.00 [1066.8]
UNIT AND UNGROUNDED SURFACES, POWER ENTRY S_DE .38.00 [914.0]
UNiT AND BLOCK OR CONCRETE WALLS AND OTHER
GROUNDED SURFACES, POWER ENTRY SIDE ......................... 42.00 [I088.8]
REQUIRED CLEARANCE FOR OPERATION AND SERVICING
INCHES [ram]
CONDENSER COIL ACCESS SiDE .............................................. 30.00 [762.0]
POWER ENTRY SiDE .................................................................... 30,00 [762.0]
(EXCEPT FOR NEC REQUIREMENTS)
UNIT TOP ....................................................................................... 48.00 [I 219.2]
SIDE OPPOSITE DUCTS .............................................................. 30.00 [782.0]
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 (38,00 in [914.0 ram], A
removable fence or barricade requires no clearance.
2. Dimensions are in inches. Dimensions in [ ] are in millimeters,
3! .99
[812.5]
()TT,3_t ,F IT
T
f 9WRESSO PSNEL_,
FRONT VIEW
i
BL{}ii_iE_ CC4TR(bLBOX;,!41}E'AP COIL
i,,({}ES } _A EL
2.72
[69.01 2! .6! [549.0]
0 188 DIAI
'[2212]
//
,
L. ,, i.
TTTTT _ 77777777777!77777777777777777777_
'! 2o /
[30.6] C 19.61 _ _.. 1.00
/[498. ! ] [25.4]
1.0840 I.D. X .50 DEEP /RIGHT SiDE ViEW
[26.772] X 12.7
C00158
Fig. 4- Base []nit Dimensions, 50ZH060
UNIT
50ZH060
ELECTRICAL CHARACTERISTICS
208/230 - 1-60
UNIT WEIGHT
Ib kg
355 161
CENTER OI= GRAVITY IN. (MM)
XYZ
14.0 20.0 16.0
(356) (508) (406)

ELECTRICALSHOCK HAZARD
Failure to follow this warning could result in personal
injury or death.
Before installing or servicing system, always turn off main
power to system and install lockout tag. There may be
more than one disconnect switch.
CUT HAZARD
Failure to follow this caution may result in personal injury.
Sheet metal parts may have sharp edges or burrs. Use care
and wear appropriate clothing.
These instructions cover minimum requirements and conform to
existing national standards and safety codes. In some instances,
these instructions exceed certain local codes and ordinances,
especially those that may not have kept up with changing
residential construction practices. We require these instructions as a
minimum for a safe installation.
INTRODUCTION
50ZH heat pump units are fully self-contained and designed for
outdoor installation. See Fig. 1. As shown in Fig. 2-4, units are
shipped in a horizontal-discharge configuration for installation on
a ground-level slab. All units can be field-converted to downflow
discharge configurations for rooftop applications with a
field-supplied plenum
RECEIVING AND INSTALLATION
Step 1 -- Check Equipment
IDENTIFY UNIT -- The unit model number and serial number
are stamped on the unit identification plate. Check this information
against shipping papers. Verify that unit voltage and amperage
listed on unit rating plate agree with power supplied for equipment.
INSPECT SHIPMENT -- Inspect for shipping damage while unit
is still on shipping pallet. If unit appears to be damaged or is torn
loose from its securing points, have it examined by transportation
inspectors before removal. Forward claim papers directly to
transportation company. Manufacturer is not responsible for any
damage incurred in transit.
Check all items against shipping list. Immediately notify the
nearest Carrier Air Conditioning office if any item is missing.
To prevent loss or damage, leave all parts in original packages until
installation.
Step 2 -- Provide Unit Support
SLAB MOUNT -- Place the unit on a rigid, level surface, suitable
to support the unit weight. The flat surface should extend
@proximately 2-in. (51 mm) beyond the unit casing on the 2
sides. The duct connection side and condensate drain connection
sides should be flush with the edge of the flat surface. A concrete
pad or a suitable fiberglass mounting pad is recommended.
A 6-in. wide gravel apron should be used around the flat surface to
prevent airflow blockage by grass or shrubs. Do not secure the unit
to the flat surface except where required by local codes.
The unit should be level to within 1/4 in. (6 mm) This is necessary
for the unit drain to flmction properly.
GROUND MOUNT -- The unit may also be installed directly on
the ground if local codes permit. Place unit on level ground
prepared with gravel for condensate discharge.
Step 3 -- Provide Clearances
The required minimum service clearances and clearances to
combustibles are shown in Fig. 2-4. Adequate ventilation and
condenser air must be provided.
The condenser fan pulls air through the condenser coil and
discharges it through the fan on the top cover. Be sure that the fan
discharge does not recirculate to the condenser coil. Do not locate
the unit in either a corner or under an overhead obstruction. The
minimum clearance under a partial overhang (such as a normal
house overhang) is 48 in. (1219 mm) above the unit top. The
maximum horizontal extension of a partial overhang must not
exceed 48 in. (1219 mm).
Do not place the unit where water, ice, or snow from an overhang
or roof will damage or flood the unit. The unit may be installed on
wood flooring or on Class A, B, or C roof covering materials.
IMPORTANT: Do not restrict outdoor airflow. An air restriction
at either the outdoor-air inlet or the fan discharge may be
detrimental to compressor life.
Step 4-- Place Unit
[]nit can be moved with the handholds provided in the unit
basepan. Refer to Table 1 for operating weights. Use extreme
caution to prevent damage when moving the unit. []nit must
remain in an upright position during all moving operations. The
unit must be level for proper condensate drainage; the
ground-level pad must be level before setting the unit in place.
When a field-fabricated support is used, be sure that the support is
level and that it properly supports the unit.
Step 5 -- Select and Install Ductwork
The design and installation of the duct system must be in
accordance with:
• the standards of the NFPA (National Fire Protection Association)
for installation of nonresidence-type air conditioning and
ventilating systems;
• NFPA90A or residence-type, NFPA90B; and/or local codes and
residence-type, NFPA 90B;
• and/or local codes and ordinances.
Select and size ductwork, supply-air registers and return-air grilles
according to ASHRAE (American Society of Heating,
Refrigeration, and Air Conditioning Engineers) recommendations.
Use the duct flanges provided on the supply- and return-air
openings on the side of the unit. See Fig. 2-4 for connection sizes
and locations. The 14-in. (356 mm) round duct collars (size
024-048 units) are shipped inside the unit attached to the indoor
blower. They are field-installed and must be removed from the
indoor cavity prior to start-up, even if they are not used for
installation.
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.
6. Ductwork can now be attached to flanges.

Whendesigningandinstallingductwork,considerthe following:
UNIT DAMAGE HAZARD
Failure to follow this caution may result in damage to unit
components.
When connecting ductwork to units, do not drill deeper
than 3/4 in. (19 mm) 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.
IMPORTANT: Use flexible connectors between ductwork and
unit to prevent transmission of vibration. Use suitable gaskets to
ensure weathertight and airtight seal. If flexible duct is used, insert
a sheet metal sleeve inside duct. Heat resistant duct connector (or
sheet metal sleeve) must extended 24-in. (610 mm) from the unit
discharge connection flange into the ductwork.
• Size ductwork for cooling air quantity (cfm).
• Insulate and weatherproof all external ductwork. Insulate and
cover with a vapor barrier all ductwork passing through
conditioned spaces. Follow latest Sheet Metal and Air
Conditioning Contractors National Association (SMACNA) and
Air Conditioning Contractors Association (ACCA) minimum
installation standards for residential heating and air conditioning
systems.
• Secure all ducts to building structure. Flash, weatherproof, and
vibration-isolate duct openings in wall or roof according to good
construction practices.
Fig. 8 shows a typical duct system with 50ZH unit installed.
HAND FORM
STRAIGHT PIECE
Fig. 6 -Flanges Installed on 50ZH060 Units
C00006
Converting Horizontal Discharge Units to Downflow
(Vertical) Discharge
ELECTRICAL SHOCK HAZARD
Failure to follow this warning could result in personal
iniury or death.
Before performing service or maintenance operations on the
system, turn off main power to unit and install lockout tag.
Units are dedicated side supply products. They are not convertible
to vertical air supply. A field-supplied plenum must be used to
convert to vertical air discharge.
Step 6-- Provide for Condensate Disposal
NOTE: Be sure that condensate-water disposal methods comply
with local codes, restrictions, and practices.
Unit removes condensate through a 1 3/64 -in. (26.6 mm) ID hole
which is located at the end of the unit. See Fig. 2-4 for location of
condensate connection.
FWE PIECES OF DUCT
FLANGE ATTACHED
HERE FOR SHIPMENT
C00005
Fig. 5 -Shipping Location of Duct Flanges (Size 060 Only) Fig. 7 - Area Not to Be Drilled More Than 3/4-in.
C00007

DRAIN
CONNECTION
Fig. 8 - Typical Installation A10018
1" (25 mm) MtN TRAP
OUTLET Z
2'21 ram)M,N
A08001
Fig. 9 - Condensate Trap Using Tubing
l-irJ. (25 ram) mirJ.
TRAP
mm) mirJ.
A09052
Fig. 10 - PVC Condensate Trap
UNIT 50ZH
OPERATING WEIGHT (Ibs)
(kg)
COMPRESSOR TYPE
REFRIGERANT Charge (Ib)
(kg)
REFRIGERANT METERING DEVICE
Table 1 - Physical Data
024 030 036
267 295 319
121 134 145
3.7 5.8 5.9
1.7 2.6 2.7
O42
342
155
Scroll
R-226.6
3.0
Acul "ol"_ System
CONDENSER COIL Copper Tubes, Aluminum Plate Fins
Rows...Fins/in,
Face Area (sq ft)
CONDENSER-FAN
MOTOR CFM
Nominal Rpm
Motor Hp
Diameter (in.)
(mm)
EVAPORATOR COIL
Rows...Fins/in,
Face Area (sq ft)
EVAPORATOR FAN MOTOR
Blower Motor Size (in.)
(mm)
Nominal Cfm
Rpm Range
Number of Speeds
Factory Speed Setting
Motor Hp
CONNECTING DUCT SIZES
Supply Air (in.)
(mm)
Return Air (in.)
(mm)
FIELD-SUPPLIED RETURN-AIR FILTER1-
Throwaway (in.)
(mm)
1...17 2...17
7.9 6.7
18OO
825
1/8
2O
5O8
2...15
3.1
10x8
254x203
800
550-1000
3
Low
1/4
2000
1100
1/4
20
5O8
3...15
3.1
10x8
254x203
1000
550-1000
3
Med
1/4
048 060
373 418
169 190
9.1 9.7
4.1 4.4
1...17 2...17 2...17
11.1 9.3 11.1
_ropeller
2600 2600
1100 1100
1/4 1/4
20 20
508 508
Copper Tubes, Aluminum Plate Fins
3...15
4.0
2...17
12.7
10x9
254x229
1200
800-1050
3
Low
1/2
Round
14
356
14
356
24 x 24
610 x 610
2600 3200
1100 1100
1/4 1/2
20 20
508 508
10x9
254x229
1600
1000-1100
2
Low
3/4
3...15 3...15
4.0 4.4
D rect Drive
10x9
254x229
1400
800-1050
3
Med
1/2
4...15
4.9
10x10
254x254
2000
950-1100
3
Low
1
Square
13.9 x 13.9
353 x 353
13.9 x 27.8
353 x 706
24 x 30
610 x 762
24 x 24 24 x 24 24 x 24 24 x 30
610 x 610 610 x 610 610 x 610 610 x 762
"i-Required filter sizes shown are based on the AHRI (Air Conditioning, Heating 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. (25 mm) thick.

HIGH-VOLTAGE LOW-VOLTAGE
POWER WIRING WIRING ENTRY
ENTRY HOLE HOLE
o
c, @', o
Fig. 11 -[]nit Electrical Connection Entry Holes
C00010
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. (25 mm) lower than the
drain-pan condensate connection to prevent the pan from
overflowing. Prime the trap with water. When using a gravel apron,
make sure it slopes away from the unit.
If the installation requires draining the condensate water away from
the unit, install a 2-in. (51 mm) 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. (25 mm) 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 (3 m) 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.
Step 7 -- Install Electrical Connections
ELECTRICAL SHOCK HAZARD
Failure to follow this warning could result in personal
injury or death.
The unit cabinet must have an uninterrupted, unbroken
electrical ground to minimize the possibility of personal
injury if an electrical fault should occur. This ground may
consist of an electrical wire connected to the unit ground
screw in the control compartment, or conduit approved for
electrical ground when installed in accordance with NEC,
ANSI/NFPA 70 American National Standards Institute/
National Fire Protection Association (latest edition) (in
Canada, Canadian Electrical Code CSA C22.1) and local
electrical codes.
[]NIT COMPONENT DAMAGE HAZARD
Failure to follow this caution may result in damage to the
unit being installed.
1. Make all electrical connections in accordance with NEC
ANSI/NFPA 70 (latest edition) and local electrical codes
governing such wiring. In Canada, all electrical
connections must be in accordance with CSA standard
C22A Canadian Electrical Code Part 1 and applicable
local codes. Refer to unit wiring diagram.
2. Use only copper conductor for connections between
field-supplied electrical disconnect switch and unit. DO
NOT USE ALUMINUM WIRE.
3. Be sure that high-voltage power to unit is within
operating voltage range indicated on unit rating plate.
Consult local power company for correction of improper
voltage.
4. Do not damage internal components when drilling
through any panel to mount electrical hardware, conduit,
etc.
HIGH-VOLTAGE CONNECTIONS -- 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.
The field-supplied disconnect may be mounted on the unit over
the high-voltage inlet hole. See Fig. 2-4.
Operation of unit on improper line voltage constitutes abuse and
may cause unit damage that could affect warranty.
ROUTING POWER LEADS INTO UNIT -- Use only copper
wire between disconnect and unit. The 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).
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.
COMPRESSOR TRANSFORMER
GROUND INDOOR OUTDOOR FAN MOTOR HIGH
LUG FAN AND COMPRESSOR VOUTAGE
RELAY START CAPACl fOR LEADS
Fig. 12 -Control Box Wiring
A10019

GROUND
SINGLE-PHASE _[77- LEAD
ICONNECTIONS 4
/TOD,SCONNEOT,.
] ERNECUL
UNIT GROUND
4]_]EQUIP GR
-_- BLK- -/
- ZY:)LyE L _ _/
Fig. 13 -Line Power Connections
A10022
©
Q
THERMOSTAT
AND SUBBASE
--L__
L__
[__
--1
UNITOONTROLPOWER
SPLICE BOX
C99056
Fig. 14 -Control Connections
ROUTING CONTROL POWER WIRES -- Form a drip-loop
with the thermostat leads before routing them into the unit. Route
the thermostat leads through grommeted hole provided in unit (see
Fig. 11) into unit control box. Connect thermostat leads to unit
control power leads as shown in Fig. 13 and 14.
Route thermostat wires through grommet providing a drip-loop at
the panel. Connect low-voltage leads to the thermostat as shown in
Fig. 14.
The unit transformer supplies 24-v power for complete system.
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 Operation section below.
SPECIAL PROCEDURES FOR 208-V OPERATION
ELECTRICAL SHOCK HAZARD
Failure to follow this warning could result in personal
iniury or death.
Before performing service or maintenance operations on the
system, turn off main power to unit and install lockout tag.
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.
3. Save the wirenut.
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.
PRE-START-UP
FIRE, EXPLOSION, ELECTRICAL SHOCK
HAZARD
Failure to follow this warning could result in personal
iniury or death and/or property damage.
1. Follow recognized safety practices and wear protective
goggles when checking or servicing refrigerant system.
2. Relieve and recover all refrigerant from system before
touching or disturbing anything inside terminal box if
refrigerant leak is suspected around compressor
terminals.
3. Never attempt to repair soldered connection while
refrigerant system is under pressure.
4. Do not use torch to remove any component. System
contains oil and refrigerant under pressure.
5. To remove a component, wear protective goggles and
proceed as follows:
a. Shut off electrical power to unit and install
lockout tag.
b. Relieve and reclaim all refrigerant from system
using both high- and low-pressure ports.
c. Cut component connecting tubing with tubing
cutter and remove component from unit.
d. Carefully unsweat remaining tubing stubs when
necessary. Oil can ignite when exposed to flame.
Use the Start-Up Checklist supplied at the end of this book and
proceed as follows to inspect and prepare the unit for initial
start-up:
1. Remove all access panels.
2. Read and follow instructions on all DANGER, WARNING,
CAUTION, and INFORMATION labels attached to, or
shipped with, unit.
Make the following inspections:
a. Inspect for shipping and handling damages such as
broken lines, loose parts, disconnected wires, etc.
b. Inspect for oil at all refrigerant tubing connections and
on unit base. Detecting oil generally indicates a
refrigerant leak. Leak-test all refrigerant tubing
connections using electronic leak detector, or
liquid-soap solution. If a refrigerant leak is detected, see
following Check for Refrigerant Leaks section.
c. Inspect all field- and factory-wiring connections. Be
sure that connections are completed and tight. Ensure
wires do not contact refrigerant tubing or sheet metal
edges.
d. Inspect coil fins. If damaged during shipping and
handling, carefully straighten fins with a fin comb.
3. Verify the following conditions:
a. Make sure that outdoor-fan blade is correctly positioned
in fan orifice. Top edge of blade should be 3.125 in. (79
mm) down from condenser outlet grille (size 024-048,
See Fig. 21) or hub should be 0.708-in. (18 mm) away
from motor end bell (size 060, See Fig. 22). See
Condenser Fan section.
b. Make sure that air filter is in place.
c. Make sure that condensate drain pan and trap are filled
with water to ensure proper drainage.
d. Make sure that all tools and miscellaneous loose parts
have been removed.

MAXINU_ WIRE
SIZE 2 AWB
SCHEMATIC
208/230-I-60 BLK
[FR
iOR_.O3e,OAB,eAB & 060)
OFN
BLU OVERLOAD PROTECTOR
l-
BLK
t[YEL- < q ) oNR
THE RNOSTAT SUB'BASE
FAT_
oOFF
I
B
I I
JI
I
{SEE ROTE_B)
ROTES
I,_F ARY OF THE OBIOIRAL WIRE FURNISHED
RUST BE REPLACED. IT WBST BE REPLACED
WITH TYPE BOrG WIRE OR ITS EOBIVALERT,
B,SEE PRICE PAGES FOR THEBNOSTAT
AND SUBBASE PART RBNBEBS.
R. BET HEAT ANTICXPATOR AT ,G
_,USE 7_C COPPER CONDUCTORS ORLY.
5,WB IS CORRECTED ONLY IF EXTERNAL
HEATING SOURCE IS USED.
:-q r
l l :=oo,;=ooo,,,o
SEE 3._ ANRCWARUALRESET)_ TRAN/"
ROTE 5 LOAD SIDE _ CB r_ /_
"TEL ORFI ........................ L_3_5' ORB/_ --
O_ _[ _ST OFT
m__-B_u--I I_ BLR_ BLR_i_BBR_EBROR
PL_ _-BR_ BRU_
!
_CRR BRN_ RRI
CONPRESBOR DELAY
0,5 SEC I F÷5 NIe.
C_ C_
CLOSES OP[RS
(TSTAT)
BLR_
YEL-.._ OEW)
BBR_
||
R_V SPLICE
BOX
COMPONENT ARRANGEMENT
INDOOR FAR
BLOWER HOUSING
BRC
GBR-YEL_
BL_ """"""-f _% ELd
BLURB
BRR
_ IORG)
CAP?
BUN /i,OFW CAPI
[FR CAP
_PL ICE
_av POWER [RFRY _ m_
FAN SEORENCE
TDR // //// /
I 0 IT*RO
G G
ERERBIEED DE-ENERGIZED T:RO
LEGEND
FIELD SPLICE B CONTACTOR,CONPRESSOR
CAP CAPACIFOR
WARNED WIRE CB CIRCUIT BREAKER
@TZRNIRAL UNARKEB) CO_P CO_PRZSSOB NOFOB
_TB BONPRESSOR FINE BELAY
0TERWINAL {UNNARKED} EOUXP EOUIPWENT
TERNIRAL BLOC_ KU FUSE
GRB GROURD
@SPL(CE DB DEFROST BOARD
SPLICE (NARKEDI DFT DEFROSF THERWOSFAT
PlUG DR DEFROST RELAY
DT DISCHARGE TNERWOSTAT
--< RECEPTACLE IFR I_B_R FAN RELAY
IFW INDOOR FAN WO_OR
FACTORY _]RING LPB LOW PRESSURE SWITCH
KIELB CORTROL WIRING OFN OUTDOOR FAN NOTOR
PL PLUG
KIELC PO_ER WIRING OT OUADRUPLE TERRINAL
RVS REVERSING VALVE SOLENOID
_ ACCESSORY OR OPTIONAL WIRING SB SLOW BLOW FUSE
TDR TIRE BELNY RELAY
TO INDICATE CO_O_ TRAR TRARBFOBWEK
POTENTIAL ONLY:
ROT TO REPRESENT WIRING
0 H O0 6 k
A10095
Fig. 15 -50ZH 208/230-1 Wiring Diagram
10

START-UP
Use the Start-Up Checklist supplied at the end of this book, and
proceed as follows:
Step 1-- Check for Refrigerant Leaks
LOCATE AND REPAIR REFRIGERANT LEAKS AND
CHARGE THE UNIT AS FOLLOWS:
1. Using both high- and low-pressure ports, locate leaks and
reclaim remaining refrigerant to relieve system pressure.
2. Repair leak following accepted practices.
NOTE: Install a filter drier whenever the system has been opened
for repair.
Step 2 -- Start-Up Cooling Section and Make
Adjustments
Complete the required procedures given in the Pre-Start-Up
section 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 (4°C).
Do not rapid-cycle the compressor. Allow 5 minutes between "on"
cycles to prevent compressor damage.
CHECKING COOLING CONTROL OPERATION
Start and check the unit for proper cooling control operation as
follows:
1. Place room thermostat SYSTEM switch in OFF position.
Observe that blower motor starts when FAN switch is
placed in ON position and shuts down within 30 seconds
when FAN switch is placed in AUTO position.
2. Place SYSTEM switch in COOL position and FAN switch
in AUTO position. Set cooling control below room
temperature. Observe that compressor, condenser fan, and
evaporator blower motors start and that valves shirts.
Observe that cooling cycle shuts down when control setting
is satisfied. Reversing valve (RV) remains energized.
3. Place system switch in HEAT position. Observe that
compressor, indoor fan and outdoor fan energize (Reversing
Valve is deenergized in heat pump heating mode). Set
control above room temperature. Observe that heating cycle
shuts down when control setting is satisfied.
4. When using an automatic changeover room thermostat,
place both SYSTEM and FAN switches in AUTO
positions. Observe that unit operates in Cooling mode when
temperature control is set to "call for cooling" (below room
temperature), and unit operates in Heating mode when
temperature control is set to "call for heating" (above room
temperature).
Step 3-- Refrigerant Charge
Amount of refrigerant charge is listed on unit nameplate (also refer
to Table 1).
Unit panels must be in place when unit is operating during
charging procedure. Unit must operate a minimum of 15 minutes
before checking charge.
NO CHARGE -- Use standard evacuating techniques. After
evacuating system, weigh in the specified amount of refrigerant
(refer to Table 1).
LOW CHARGE COOLING -- Use Cooling Charging Charts, Fig.
16-21. Vary refrigerant until the conditions of the appropriate chart
are met. Note that charging charts are different from the type
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 are required.
Connect the pressure gage 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.
TO USE COOLING CHARGING CHARTS
This method is to be used in cooling mode only. Take the outdoor
ambient temperature and read the suction pressure gauge. Refer to
charts to determine what the suction temperature should be. If
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.
EXAMPLE: (Fig. 16)
Outdoor Temperature ..................... 85 °F (29 ° C)
Suction Pressure ....................... 74 psig
Suction Temperature should be ............. 60 °F (16 ° C)
(Suction Temperature may vary _+5°F (2.8°C)
HEATING MODE CHARGE
Do not attempt to adjust charge by cooling methods while in heat
pump heating mode. Recover refrigerant and weigh in according to
unit data plate refrigerant data,
Step 4-- Indoor Airflow and Airflow Adjust-
ments
NOTE: For cooling operation, the recommended airflow is 350
to 450 CFM for each 12,000 Btuh of rated cooling capacity.
Table 2 shows dry coil air delivery for horizontal discharge units.
Tables 3- 4 show pressure drops.
NOTE: Be sure that all supply- and return-air grilles are open,
free from obstructions, and adjusted properly.
ELECTRICALSHOCK HAZARD
Failure to follow this warning could result in personal
iniury or death.
Disconnect electrical power to the unit and install lockout
tag before changing blower speed.
Airflow can be changed by changing the lead connections of the
blower motor.
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.
FOR 208/230-V -- The motor leads are color-coded as follows:
3-SPEED 2-SPEED
black = high speed black = high speed
blue = medium speed
red = low speed red = low speed
To change the speed of the indoor fan motor (IFM), remove the fan
motor speed leg lead from the indoor (evaporator) fan relay (IFR)
with units 024, 030, 042, 048 and 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.
11

SUCTION LINE TEMPERATURE
Fig. 16 - Cooling Charging Chart, 50ZH024
7O 8O
SUCTION LINE TEMPERATURE
Fig. 17 -Cooling Charging Chart, 50ZH030 Units
C00162
C00163
7581 tt0-
207m 30 -
30
-1-
60 70
SUCTION LiNE TEMPERATURE
40 50 8O
4 10 t6 21 27 32
SUCTION LINE TEMPERATURE i
9O
C00164
Fig. 18 -Cooling Charging Chart, 50ZH036 Units
7581 tt0-
2071 30 -
30 40 50
SUCTION LINE TEMPERATURE _ 9O
4 10 t6 21 27 32
SUCTION LINE TEMPERATURE _
C00165
Fig. 19 -Cooling Charging Chart, 50ZH042 Units
12

6O 7O
SUCTION LINETEMPERATURE,
Fig. 20 - Cooling Charging Chart, 50ZH048 Units
C00166
SUCTION LINETEMPERATURE
C00167
Fig. 21 -Cooling Charging Chart, 50ZH060 Units
Step 5-- Unit Controls
All compressors have the following internal-protection controls.
HIGH-PRESSURE RELIEF VALVE
This valve opens when the pressure differential between the low
and high side becomes excessive. (024 size has temperature relief
only).
LOSS OF CHARGE SWITCH
Located on the outdoor liquid line is a low-pressure switch which
functions as a loss-of charge switch. This switch contains a
Schrader core depressor. This switch opens at 7 psig and closes at
22 psig. No adjustment is necessary.
COMPRESSOR OVERLOAD
This overload interrupts power to the compressor when either the
current or internal temperature become excessive, and
automatically resets when the internal temperature drops to a safe
level. This overload may require up to 60 minutes (or longer) to
reset; therefore, if the internal overload is suspected of being open,
disconnect the electrical power to the unit and check the circuit
through the overload with an ohmmeter or continuity tester.
Step 6-- Sequence of Operation
FAN OPERATION -- The FAN switch on the thermostat controls
indoor fan operation. When the FAN switch is placed in the ON
position, the IFR (indoor-fan relay) is energized through the G
terminal on the thermostat. The normally-open contacts close,
which then provide power to the indoor (evaporator) fan motor
(IFM). The IFM will run continuously when the FAN switch is set
to ON.
When the FAN switch is set to AUTO, the thermostat deenergizes
the IFR (provided there is not a call for cooling). The contacts open
and the IFM is deenergized. The IFM will be energized only when
there is a call for cooling.
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.
COOLING
With the thermostat subbase in the cooling position, the thermostat
makes circuit R-). This energizes the reversing valve solenoid
(RVS) and places the unit in standby condition for cooling.
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
compressor and the outdoor (condenser) fan motor (OFM).
Energizing the IFR provides power to the IFM.
When the need for cooling has been satisfied, the OFM,
compressor, 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.
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 I-second delay.
When thermostat is satisfied, contacts open, deenergizing contactor
and relay; motors deenergize. The IFM may be controlled by a
time-delay relay that keeps the fan on for 30 seconds.
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 60
minutes and should only be adjusted by a trained service person.
Electronic timer and defrost cycle start only when contactor is
energized and defrost thermostat (DFT) is closed.
Defrost mode is identical to Cooling mode. The outdoor fan motor
stops because of "OFI" and OF2" contacts opening on the defrost
board.
13

MAINTENANCE
To ensure continuing high performance, and to reduce the
possibility 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.
NOTE: TO EQUIPMENT OWNER: Consult your local dealer
about the availability of a maintenance contract.
PERSONAL INJURY AND UNIT DAMAGE
HAZARD
Failure to follow this warning could result in personal
injury or death and possible unit component damage.
The ability to properly perform maintenance on this
equipment requires certain expertise, mechanical skills,
tools and equipment. If you do not possess these, do not
attempt to perform any maintenance on this equipment,
other than those procedures recommended in the Owner's
Manual.
The minimum maintenance requirements for this equipment are as
follows:
1. Inspect air filter(s) each month. Clean or replace when
necessary.
2. Inspect indoor coil, outdoor coil, drain pan, and condensate
drain each cooling season for cleanliness. Clean when
necessary.
3. Inspect blower motor and wheel for cleanliness each
cooling season. Clean when necessary. For first heating
season, inspect blower wheel bimonthly to determine proper
cleaning frequency.
4. Check electrical connections for tightness and controls for
proper operation each cooling season. Service when
necessary.
5. Check the drain channel in the top cover periodically for
blockage (leaves, insects). Clean as needed.
ELECTRICALSHOCK HAZARD
Failure to follow these warnings could result in personal
iniury or death:
1. Turn off electrical power and install lockout tag to the
unit before performing any maintenance or service on
this unit.
2. Use extreme caution when removing panels and parts.
3. Never place anything combustible either on or in contact
with the unit.
Step 1-- Air Filter
IMPORTANT: Never operate the unit without a suitable air filter
in the return-air duct system. Always replace the filter with the
same dimensional size and type as originally installed. See Table 1
for recommended filter sizes.
Inspect air filter(s) at least once each month and replace
(throwaway-type) or clean (cleanable-type) at least twice during
each cooling season or whenever the filters become clogged with
dust and lint.
Replace filters with the same dimensional size and type as
originally provided, when necessary.
Step 2 -- Unit Top Removal (Condenser-Coil
Side)
NOTE: When performing maintenance or service procedures that
require removal of the unit top, be sure to perform all of the routine
maintenance procedures that require top removal, including coil
inspection and cleaning, and condensate drain pan inspection and
cleaning.
ELECTRICALSHOCK HAZARD
Failure to follow this warning could result in personal
iniury or death.
Disconnect electrical power, and install lockout tag to the
unit before removing top.
Only qualified service personnel should perform maintenance and
service procedures that require unit top removal.
Refer to the following top removal procedures:
1. Remove 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.
4. Carefully replace and secure unit top to unit, using screws
removed in Steps 1 and 2, when maintenance and/or service
procedures are completed.
Step 3 -- Evaporator Blower and Motor
For longer life, operating economy, and continuing efficiency,
clean accumulated dirt and grease from the blower wheel and
motor annually.
ELECTRICALSHOCK HAZARD
Failure to follow this warning could result in personal
iniury or death.
Disconnect electrical power, and install lockout tag to the
unit before cleaning and lubricating the blower motor and
wheel.
To clean the blower wheel:
1. Access the blower assembly as follows:
a. Remove top access panel.
b. Remove 3 screws that hold blower orifice ring to blower
housing. Save screws.
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.
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.
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. (5 mm)
below bottom of orifice ring when centered correctly.
14

Be sure setscrews are tightened on motor and are not on
round part of shaft.
d. Set upper orifice ring in place with 3screws removed in
step 1.
e. Replace top access panel.
Step 4 -- Condenser Coil, Evaporator Coil, and
Condensate Drain Pan
Inspect the condenser coil, evaporator coil, and condensate drain
pan at least once heating and cooling season. Proper inspection and
cleaning requires the removal of the unit top. See []nit Top
Removal section above.
Remove all obstructions (including weeds and shrubs) that
interfere with the airflow through the outdoor coil. Straighten bent
fins with a fin comb. If coated with dirt or lint, clean the coils with
a vacuum cleaner, using a soft brush attachment. Be careful not to
bend the fins. If coated with oil or grease, clean the coils with a
mild detergent-and-water-solution. Rinse coils with clear water
using a garden hose. Be careful not to splash water on motors,
insulation, wiring, or air filter(s). For best results, spray
condenser-coil fins from inside to outside the unit. On units with
an outer and inner condenser coil, be sure to clean between the
coils. Be sure to flush all dirt and debris from the unit base.
Inspect the drain pan and condensate drain line when inspecting
the coils. Clean the drain pan and condensate drain by removing all
foreign matter from the pan. Flush the pan and drain tube with
clear water. Do not splash water on the insulation, motor, wiring, or
air filter(s). If the drain tube is restricted, clear it with a "plumbers
snake" or similar probe device. Ensure that the auxiliary drain port
above the drain tube is also clear.
Step 5-- Condenser Fan
[]NIT OPERATION HAZARD
Failure to follow this caution may result in damage to unit
components.
Keep the condenser fan free from all obstructions to ensure
proper cooling operation. Never place articles on top of
unit.
1. Shut off unit power supply and install lockout tag.
2. Remove condenser-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. 22 or 23.
5. Tighten setscrews.
6. Replace condenser-fan assembly.
Step 6 -- Electrical Controls and Wiring
Inspect and check the electrical controls and wiring annually. Be
sure to turn off the electrical power to the unit and install lockout
tag.
Remove the top panel to locate all the electrical controls and
wiring. Check all electrical connections for tightness. Tighten all
screw connections. If any smoky or burned connections are
noticed, disassemble the connection, clean all the parts, restrip the
wire end and reassemble the connection properly and securely,
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,
15

Unit
Table 2-Dry Coil Air Delivery* Horizontal Discharge (Deduct 10%for 208 Volt Operation)
Motor Speed
Low
Med
High
Low
Med
High
Low
Med
High
Low
Med
High
Low
Med
High
Low
Med
0.8 0.9
External Static Pressure (IN.W.C.)
Waffs/CFM 0.1 0.2 0.3 0.4 0.5 0.6 0.7
Wa_s 288 285 282 279 274 268 261
Cfm 875 820 802 734 668 582 478
Wa_s 390 383 378 369 360 350 340
Cfm 1131 1090 1038 978 917 830 721
Wa_s 528 520 510 495 480 460 450
Cfm 1391 1338 1285 1200 1115 1018 920
Wa_s 288 285 282 279 274 268 261
Cfm 875 820 802 734 668 582 478
Wa_s 390 383 378 369 360 350 340
Cfm 1131 1090 1038 978 917 830 721
Wa_s 528 520 510 495 480 460 450
Cfm 1891 1338 1285 1200 1115 1018 920
Wa_s 450 435 420 400 380 365 326
Cfm 1231 1218 1204 1120 1008 950 863
Wa_s 470 450 445 410 388 359 368
Cfm 1302 1264 1205 1163 1081 940 873
Wa_s 660 635 610 575 540 505 485
Cfm 1700 1660 1581 1450 1297 1190 1095
Wa_s 478 458 440 411 378 350 327
Cfm 1303 1270 1224 1179 1126 1022 911
Wa_s 481 468 450 438 404 370 368
Cfm 1310 1280 1241 1181 1110 1022 943
Wa_s 798 678 647 618 578 540
Cfm 1736 1688 1618 1510 1421 1309
Wa_s 801 760 730 688 650
Cfm 1898 1841 1757 1682 1564
Wa_s
Cfm
Wa_s
Cfm
Wa_s
Cfm
Wa_s
Cfm
Wa_s
Cfm
O24
O3O
311
751
321
036 783
46O
999
317
816
320
042 811
500 460
1187 1060
600 570
1429 1333
048
870 842 818 782
2000 1903 1799 1718 1625
890 850 810 790 735 680
1834 1820 1791 1762 1703 1640
1040 1018 1000 950 890 835
060 2230 2102 2025 1960 1901 1855
1073 1038 1001 958 896 840
High 2230 2202 2160 2122 2052 1926
* Air delivery values are based on operating voltage of 230 v dry coil, without filter. Deduct wet coil, filter pressure drops to obtain
able for ducting.
See Tables 3-4.
NOTES:
696 632 628
1446 1365
580 480 422
1415 1159 950
790 650 580
1752 1468 1121
800 691 575
1791 1588 1202
externalstatic pressure avail-
1. 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.
2. Dashes indicate portions of the table that are beyond the blower motor capacity or are not recommended.
Table 3 - Wet Coil Pressure Drop
UNIT SIZE 50ZH AIRFLOW (CFM)
024
030
036
042
6OO
7OO
8OO
9OO
9OO
1000
1200
1000
1200
1400
1600
1000
1200
1400
1600
1400
1600
1800
1700
1800
2100
2300
PRESSURE DROP (IN. W.C.)
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
048
060
UNIT SIZE 50ZH
024-042
048,060
UNIT SIZE 50ZH
024-042
FILTER SIZE IN. (mm)
24 x 24
(810 x 610)
24 x 30
(610 x 762)
Table 4 - Filter Pressure Drop (IN. W.C.) GFM
500 600 700 800 900 1000
0.06 0.07 0.08 0.08 0.09 0.09
1100 1200 1300 1400
0.09 0.10 0.11 0.12
0.08
CFM
FILTER SIZE IN. (mm)
24 x 24
(810 x 610)
24 x 30
(610 x 762)
0.09
1500 1600 1700 1800 1900 2000 2100 2200 2300
0.14 0.15
048,060 0.10 0.11 0.12 0.13 0.14 0.15 0.16 0.17 0.18
ld

Fig. 22 -Condenser-Fan Adjustment
C00021
C02017
Fig. 23 - Condenser-Fan Adjustment (060 Size)
After inspecting the electrical controls and wiring, replace all the
panels. Start the unit, and observe at least one complete cooling
cycle to ensure proper operation. If discrepancies are observed in
operating cycle, or if asuspected malflmction has occurred, check
each electrical component with the proper electrical
instrumentation. Refer to the unit wiring label when making these
checkouts.
NOTE: Refer to the Sequence of Operation section, as an aid in
determining proper control operation.
Step 7 -- Refrigerant Circuit
Inspect all refrigerant tubing connections and the unit base for oil
accumulations annually. Detecting oil generally indicates a
refrigerant leak.
If oil is detected or if low cooling performance is suspected,
leak-test all refrigerant tubing using an electronic leak-detector, or
liquid-soap solution. If a refrigerant leak is detected, refer to Check
for Refrigerant Leaks section
If no refrigerant leaks are found and low cooling performance is
suspected, refer to Refrigerant Charge section.
Step 8-- Evaporator 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 Ac[iustments section to check the system
airflow.
Step 9 -- Metering Devices
Refrigerant metering devices are fixed orifices and are located in
the inlet header to the indoor and outdoor coil.
Step 10 -- Lubrication
COMPRESSOR - The compressor is charged with the correct
amount of oil at the factory.
FAN MOTOR BEARINGS - Fan motor bearings are permanently
lubricated. No further lubrication of outdoor or indoor fan motors
is required.
Step 11 -- Liquid Line Strainer
The liquid line strainer (to protect metering device) is made of wire
mesh and is located in the liquid line on the inlet side of the
metering device.
Check valves are also located in the liquid lines near the strainers.
The Strainers are the larger of the two components.
Step 12 -- High Flow Valves
Located on the compressor hot gas and suction tubes are High
Flow Valves. Large black plastic caps distinguish these valves with
O-rings located inside the caps. These valves 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.
TROUBLESHOOTING
Refer to the Troubleshooting Chart (Table 5) for troubleshooting
information.
START-UP CHECKLIST
Use the Start-Up Checklist at the back of this manual.
17

SYMPTOM
Compressor and outdoor fan will not start
Compressor will not start but condenser fan
runs
Compressor cycles
(other than normally satisfying thermostat)
Compressor operates continuously
Excessive head pressure
Head pressure too low
Excessive suction pressure
Suction pressure too low
Table 5 - Troubleshooting Chart
CAUSE
Power failure
Loss of Charge Switch Open
Fuse blown or circuit breaker tripped
Defective thermostat, contactor, transformer, or
control relay
Insufficient line voltage
Incorrect or faulty wiring
Thermostat setting too low/too high
Faulty wiring or circuit
Loose connections in compressor
Compressor motor burned out, seized, or
internal overload open
Defective run/start capacitor, overload start relay
Low input voltage
Refrigerant overcharge or undercharge
Loss of Charge Switch Open
Defective compressor
Insufficient line voltage
Blocked outdoor coil
Defective run/start capacitor, overload or start relay
Defective thermostat
Faulty outdoor fan motor or capacitor
Restriction in refrigerant system
Dirty air filter
Unit undersized for load
Thermostat temperature set too low
Low refrigerant charge
Leaking valves in compressor
Frosted outdoor coil with incorrect defrost operation
(heating)
Air in system
Outdoor coil dirty or restricted
Dirty air filter
Dirty indoor or outdoor coil
Refrigerant overcharged
Air in system
Indoor or outdoor air restricted or air short-cycling
Low refrigerant charge
Compressor valves leaking
Restriction in liquid tube
High Heat load
Compressor valves leaking
Refrigerant overcharged
Dirty air filter
Low refrigerant charge
Metering device or low side restricted
Insufficient coil airflow
Temperature too low in conditioned area
Outdoor ambient below 55°F (13°C)
Filter drier restricted
Compressor runs but outdoor fan does not Normally closed contacts on defrost board open
REMEDY
Call power company
Evaluate unit for possible refrigerant leak
Replace fuse or reset circuit breaker
Replace component
Determine cause and correct
Check wiring diagram and rewire correctly
Reset thermostat setting
Check wiring and repair or replace
Determine cause
Replace compressor
Determine cause and replace
Determine cause and correct
Recover refrigerant, evacuate system, and re-
charge to capacities shown on rating plate
Evaluate unit for possible refrigerant leak
Replace and determine cause
Determine cause and correct
Determine cause and correct
Determine cause and replace
Replace thermostat
Replace
Locate restriction and remove
Replace filter
Decrease load or increase unit size
Reset thermostat setting
Locate leak, repair, and recharge
Replace compressor
Check defrost time settings, Reset as neces-
sary. Check defrost temperature switch.
Replace as necessary.
Recover refrigerant, evacuate system, and re-
charge
Clean coil or remove restriction
Replace filter
Clean coil
Recover excess refrigerant
Recover refrigerant, evacuate system, and re-
charge
Determine cause and correct
Check for leaks, repair and recharge
Remove restriction
Remove restriction
Check for source and eliminate
Replace compressor
Recover excess refrigerant
Replace filter
Check for leaks, repair and recharge
Remove source of restriction
Check filter-replace if necessary
Reset thermostat setting
Install low-ambient kit
Replace
Check condition of relay on board.
Replace board if necessary.
18

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.
IlL START-UP
Supply Voltage: L1-L2 L2-L3 L3-L1
Compressor Amps: LI(C) L2(S) L3(R)
Indoor Fan Amps: Outdoor Fan Amps:
TEMPERATURE-Cooling Mode
Outdoor Air Temperature:
Return-Air Temperature:
Cooling Supply Air: DB
DB WB
DB WB
WB
PRESSURES-Cooling Mode
Refrigerant Suction psig
Suction Line Temp*
Refrigerant Discharge psig
Discharge Tempi-
TEMPERATURE - Heating Mode
Outdoor Air Temperature:
Return-Air Temperature:
Cooling Supply Air: DB
DB
DB WB WB
WB
PRESSURES-Heating Mode
Refrigerant Suction psig
Suction Line Temp*
Refrigerant Discharge psig
Discharge Tempi-
Verify refrigerant charge using charging tables
*Measured at suction inlet to compressor
J-Measured at liquid line leaving outdoor coil
19

Copyright 2010 Carrier Corp. • 7310 W. Morris St. • Indianapolis, IN 46231 Printed in U.S.A. Edition Date: 02/10
Manufacturer reserves the right to change, at any time, specification8 and design8 without notice and without obligations,
Catalog No: 50ZH-07SI
Replaces: 50ZH-5Sl
2O