Emerson Copeland Scroll ZR KA Series User guide

AE4-1312 R2
© 2010 Emerson Climate Technologies
Printed in the U.S.A.
1
AE4-1312 R2 January, 2005
Reformatted November 2010
Application Guidelines for 1.5 to 6.75 Ton Refrigerant
R-22, 407C, 134A Copeland Scroll®Compressors
Introduction
The ZR*KA, ZR*KC, ZR*K3, & ZR*K4 Copeland Scroll®
compressors include a wide range of capacities,
electrical options, and features. Typical model numbers
are ZR24K4-PFV and ZR81KC-TF5. This bulletin
describes the operating characteristics, design features,
and application requirements for these models. For
additional information, please refer to the online
product information accessible from the Emerson
Climate Technologies website at www.emersonclimate.
com. Operating principles of the Copeland Scroll are
described in Figure 7 at the end of this bulletin.
The ZR*KA scroll compressors are designed for air
conditioning systems only in the 12+ SEER range
but may be applied to 10 SEER A/C systems if desired.
They range in size from 16,000 to 54000 Btu/hr (4.7 to
15.8 kw-hr).
The ZR*K3 and K4 are models designed for 11+ SEER
A/C and heat pump usage ranging in size from 16,000
to 61,000 Btu/hr (4.7 to 17.9 kw-hr).
The ZR*KC models are designed for 10 SEER
A/C and heat pump usage ranging in size from 16,000
to 81,000 Btu/hr (4.7 to 23.7 kw-hr).
The models include a number of features outlined in
the matrix below:
IPR Valve-Internal Pressure Relief Valve
The internal pressure relief valve is located between
the high side and the low side of the compressor. It
is designed to open when the discharge to suction
differential pressure exceeds 375 to 450 psid (26 – 32
kg/cm2). When the valve opens, hot discharge gas
is routed back into the area of the motor protector to
cause a trip.During developmental blocked fan testing,
it is sometimes noted that the valve opens, but the
compressor does not shut off while the discharge
pressure continues to climb. This condition is normally
caused by refrigerant ood back and may be corrected
by using a more restrictive expansion device or reducing
the refrigerant charge.
Internal Temperature Protection
The Therm-O-Disc®or TOD is a temperature-sensitive
snap disc device located between the high and low
pressure side of the scroll. It is designed to open and
route excessively hot discharge gas back to the motor
protector. During a situation such as loss of charge,
the compressor will be protected for some time while
it trips on the protector. However, as refrigerant leaks
out, the mass ow and the amperage draw are reduced
and the scrolls will start to overheat. Normally, during
air conditioning operation the problem is detected
because of rising indoor temperatures before damage
is done. This may not be the case during heat pump
Motor
Frame Size*
Application IPR TOD Quiet Shut
Down
Discharge
Check Valve
Motor
Protector
AC HP
ZR16-29KC 53 X X NO X X X X
ZR16-24K4 53 X X NO X X X X
ZR16-34KA 53 X NO X X X X X
ZR38-54KA 63 X NO X X X X X
ZR18-48K3 63 X X X X X X X
ZR26-48KC 63 X X X X X X X
ZR54-61K3 70 X X X X X X X
ZR54-81KC 70 X X X X X X X
*Approximate Shell Diameter (e.g. 53 = 5.5 Inches)

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operation since backup heat will make up the decit. A
low pressure control is recommended for loss of charge
protection in heat pumps for the highest level of system
protection. A cut out setting no lower than 25 psig (2
kg/cm2) for air conditioning and 7 psig (0.5 kg/cm2) for
heat pumps is recommended. The low pressure cut-out,
if installed in the suction line to the compressor, can
provide additional protection against a TXV failed in the
closed position, outdoor fan failure in heating, a closed
liquid line or suction line service valve, or a blocked liquid
line screen, lter, orice, or TXV. All of these can starve
the compressor for refrigerant and result in compressor
failure. The low pressure cut-out should have a manual
reset feature for the highest level of system protection. If
a compressor is allowed to cycle after a fault is detected,
there is a high probability that the compressor will be
damaged and the system contaminated with debris from
the failed compressor and decomposed oil. If current
monitoring to the compressor is available, the system
controller can take advantage of the compressor TOD
and internal protector operation. The controller can lock
out the compressor if current draw is not coincident with
the contactor energizing, implying that the compressor
has shut off on its internal protector. This will prevent
unnecessary compressor cycling on a fault condition
until corrective action can be taken.
Quiet Shut down
All scrolls in this size range have one of several
types of “quiet” shutdown solutions. The ZR..KC/K3/
K4 Scrolls up to four tons use a cam-type device that
separates the scrolls when they are driven backwards
as high-pressure gas equalizes from the high side
of the compressor to the low side during shutdown.
Larger scrolls with 70 frame motors through ZR61 use
a different type of cam that stops backward rotation
during shut down. Models ZR68KC through ZR81KC
will continue to be built with the uid brake design,
so a momentary reverse rotation sound will be heard
from these compressors. The newer ZR..KA scrolls
incorporate a non dynamic discharge port check valve
that prevents high pressure gas trapped in the dome
from returning through the scroll set. All of these quiet
shut down solutions allow the scroll compressor to
restart immediately even if the system is not equalized
eliminating the need for a time delay. Development
testing should include a review of the shutdown sound
for acceptability in a particular system. Also refer to
section on “Brief Power Interruption”.
Discharge Check Valve
A low mass, disc-type check valve in the discharge tting
of the compressor prevents the high side, high pressure
discharge gas from owing rapidly back through the
compressor. This check valve was not designed to be
used with recycling pump down because it is not entirely
leak-proof.
Motor Protector
Conventional internal line break motor protection is
provided. The protector opens the common connection
of a single-phase motor and the center of the Y
connection on three-phase motors. The three-phase
protector provides primary single-phase protection. Both
types of protectors react to current and motor winding
temperature.
Field Replacement of obsolete Single Phase ZR*K1
or ZR*K2 with Equivalent Capacity ZR*K3/K4/KA/
KC, Scroll Compressors
The discharge and suction tting sizes as well as the
mounting foot pattern of the new models are identical
to the ZR*K1 or ZR*K2. Tubing location is identical in
most cases for easy eld replacement. The ZR*K1
has an external top cap thermostat to limit discharge
temperature. This feature has been replaced by the
Therm-O-Disc®located inside the new scrolls. When
replacing the ZR*K1, the top cap thermostat wires
must be removed and the control circuit wires spliced
together. See section on Compressor Replacement
after Motor Burn for further tips on eld replacement.
The replacement compressor will need a new run
capacitor if the old capacitor is more than 5 microfarads
different or the voltage rating of the old capacitor is
lower than the new one. See compressor nameplate
or Table 4 for recommended run capacitor. Note that
the ZR*KA may only be used to replace compressors
used for A/C, not heat pumps.
Application Considerations
The Copeland Scroll compressor has a number of
application characteristics that are different from those
of the traditional reciprocating compressor. These are
detailed below.
Accumulators
The use of accumulators is very dependent on the
application. The Copeland Scroll’s inherent ability to
handle liquid refrigerant during occasional operating
ood back situations make the use of an accumulator
unnecessary in standard designs such as condensing
units. Applications, such as heat pumps with orice
refrigerant control, that allow large volumes of liquid
refrigerant to ood back to the compressor during
normal steady operation can dilute the oil to such an
extent that bearings are inadequately lubricated and
wear will occur. In such a case an accumulator must
be used to reduce ood back to a safe level that the
compressor can handle. To test for ood back conditions

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and determine if the accumulator design is adequate,
please see the section entitled Excessive Liquid Flood
back Tests at the end of this bulletin. The accumulator
oil return orice should be from .040 to .055 inches (1 –
1.4 mm) in diameter depending on compressor size and
compressor ood back results. A large-area protective
screen no ner than 30 x 30 mesh (0.6 mm openings)
is required to protect this small orice from plugging.
Tests have shown that a small screen with a ne mesh
can easily become plugged causing oil starvation to the
compressor bearings.
Screens
The use of screens ner than 30 x 30 mesh (0.6mm
openings) anywhere in the system should not be
used with these compressors. Field experience has
shown that ner mesh screens used to protect thermal
expansion valves, capillary tubes, or accumulators
can become temporarily or permanently plugged with
normal system debris and block the ow of either oil or
refrigerant to the compressor. Such blockage can result
in compressor failure.
Crankcase Heat - Single Phase
Crankcase heaters are not required on single phase
compressors when the system charge is not over the
120% limit shown in Table 5. A crankcase heater is
required for systems containing more than 120% of the
compressor refrigerant charge limit listed in Table 5.
This includes long line length systems where the extra
charge will increase the standard factory charge above
the 120% limit.
Experience has shown that compressors may ll with
liquid refrigerant under certain circumstances and
system congurations, notably after longer off cycles
when the compressor has cooled. This may cause
excessive start up clearing noise or the compressor
may lock up and trip on protector several times before
starting. The addition of a crankcase heater will reduce
customer noise and dimming light complaints since the
compressor will no longer have to clear out liquid during
start. Table 6 lists the crankcase heaters recommended
for the various models and voltages.
Crankcase Heat – Three-Phase
A crankcase heater is required for three-phase
compressors when the system charge exceeds the
compressor charge limit listed in Table 5 and an
accumulator cannot be piped to provide free liquid
drainage during the off cycle (See Figure 2 and Table
6).
Pump down Cycle
A pump down cycle for control of refrigerant migration
is not recommended for scroll compressors of this size.
If a pump down cycle is used, a separate external
check valve must be added. The scroll discharge
check valve is designed to stop extended reverse
rotation and prevent high-pressure gas from leaking
rapidly into the low side after shut off. The check
valve will in some cases leak more than reciprocating
compressor discharge reeds, normally used with pump
down, causing the scroll compressor to recycle more
frequently. Repeated short-cycling of this nature can
result in a low oil situation and consequent damage to
the compressor. The low-pressure control differential
has to be reviewed since a relatively large volume of
gas will re-expand from the high side of the compressor
into the low side on shut down.
Minimum Run Time
There is no set answer to how often scroll compressors
can be started and stopped in an hour, since it is
highly dependent on system configuration. Other
than the considerations in the section on Brief Power
Interruptions, there is no minimum off time because
scroll compressors start unloaded, even if the
system has unbalanced pressures. The most critical
consideration is the minimum run time required
to return oil to the compressor after startup. To
establish the minimum run time obtain a sample
compressor equipped with a sight tube (available from
Emerson Climate Technologies) and install it in a system
with the longest connecting lines that are approved for
the system. The minimum on time becomes the time
required for oil lost during compressor startup to return
to the compressor sump and restore a minimal oil
level that will assure oil pick up through the crankshaft.
Cycling the compressor for a shorter period than this,
for instance to maintain very tight temperature control,
will result in progressive loss of oil and damage to the
compressor. See Application Engineering Bulletin 17-
1262 for more information on preventing compressor
short cycling.
Reversing Valves
Since Copeland Scroll compressors have very high
volumetric efciency, their displacements are lower
than those of comparable capacity reciprocating
compressors. As a result, Emerson recommends that
the capacity rating on reversing valves be no more than
2 times the nominal capacity of the compressor with
which it will be used in order to ensure proper operation
of the reversing valve under all operating conditions.

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The reversing valve solenoid should be wired so that the
valve does not reverse when the system is shut off by
the operating thermostat in the heating or cooling mode.
If the valve is allowed to reverse at system shutoff,
suction and discharge pressures are reversed to the
compressor. This results in pressures equalizing through
the compressor which can cause the compressor to
slowly rotate until the pressures equalize. This condition
does not affect compressor durability but can cause
unexpected sound after the compressor is turned off.
Low Ambient Cut-Out
A low ambient cut-out is not required to limit air-to-air
heat pump operation. Air-to-water heat pumps must
be reviewed since this conguration could possibly run
outside of the approved operating envelope (Figure 5)
causing overheating or excessive wear.
Oil Type
Several types of compatible mineral oils are used in
the R-22 compressors. A standard 3GS oil may be
used if the addition of oil in the eld is required. See
the compressor nameplate for original oil charge. See
Application Engineering bulletin 17-1248 for more
information about oil types Emerson uses. A complete
recharge should be four uid ounces (118 ml) less than
the nameplate value. Some models have been released
for use with R407C or 134a and use polyol ester oil,
identied as POE, along with the charge quantity on
the nameplate. These models have an “E” in the 7th
place of the model number. An example would be the
ZR24K3E-PFJ compressor. Copeland®Ultra 22 CC
should be used if additional oil is needed in the eld.
Mobil Arctic EAL22CC or ICI Emkarate RL32CF oil may
be used to recharge these compressors if Ultra 22 is
not available. Compressors charged with POE may be
used with R-22 but compressors charged with mineral
oil may not be used with HFC refrigerants such as 407C
or 134a because they are not miscible.
Discharge Mufers
Flow through Copeland Scroll compressors is semi-
continuous with relatively low pulsation. External
mufers, where they are normally applied to piston
compressors today, may not be required for Copeland
Scroll. Because of variability between systems, however,
individual system tests should be performed to verify
acceptability of sound performance. When no testing is
performed, mufers are recommended in heat pumps.
A hollow shell mufer such as the Alco APD-1 or APD-
054 will work quite well. The mufer should be located
a minimum of six inches (15 cm) to a maximum of 18
inches (46 cm) from the compressor for most effective
operation. The further the mufer is placed from the
compressor within these ranges the more effective it
may be. If adequate attenuation is not achieved, use a
mufer with a larger cross-sectional area to inlet-area
ratio. The ratio should be a minimum of 20 to 1 with a
30 to 1 ratio recommended. The mufer should be from
four to six inches (10-15 cm) long.
Air Conditioning System Suction Line Noise and
Vibration
Copeland Scroll compressors inherently have low sound
and vibration characteristics. However, the sound and
vibration characteristics differ in some respects from
those of reciprocating compressors. In rare instances,
these could result in unexpected sound complaints.
One difference is that the vibration characteristic of
the scroll compressor, although low, includes two very
close frequencies, one of which is normally isolated
from the shell by the suspension of an internally
suspended compressor. These frequencies, which
are present in all compressors, may result in a low
level “beat” frequency that may be detected as noise
coming along the suction line into a house under some
conditions. Elimination of the “beat” can be achieved
by attenuating either of the contributing frequencies.
The most important frequencies to avoid are line and
twice-line frequencies for single-phase compressors
and line frequency for three phase compressors. This is
easily done by using one of the common combinations
of design congurations described in Table 3. The scroll
compressor makes both a rocking and torsional motion,
and enough exibility must be provided in the line to
prevent vibration transmission into any lines attached to
the unit. In a split system the most important goal is to
ensure minimal vibration in all directions at the service
valve to avoid transmitting vibrations to the structure to
which the lines are fastened.
A second difference of the Copeland Scroll is that
under some conditions the normal rotational starting
motion of the compressor can transmit an “impact”
noise along the suction line. This may be particularly
pronounced in three-phase models due to their
inherently higher starting torque. This phenomenon,
like the one described previously, also results from the
lack of internal suspension, and can be easily avoided
by using standard suction line isolation techniques as
described in Table 3.
The sound phenomena described above are not usually
associated with heat pump systems because of the
isolation and attenuation provided by the reversing valve
and tubing bends.

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Single Phase Starting Characteristics
Start assist devices are usually not required, even if
a system utilizes non-bleed expansion valves. Due to
the inherent design of the Copeland Scroll, the internal
compression components always start unloaded even
if system pressures are not balanced. In addition, since
internal compressor pressures are always balanced at
startup, low voltage starting characteristics are excellent
for Copeland Scroll compressors. Starting current on
any compressor may result in a signicant “sag” in
voltage where a poor power supply is encountered. The
low starting voltage reduces the starting torque of the
compressor and subsequently increases the start time.
This could cause light dimming or a buzzing noise where
wire is pulled through conduit. The start components
listed in Table 7 will substantially reduce start time and
consequently the magnitude and duration of both light
dimming and conduit buzzing.
PTC Start Components
For less severe voltage drops or as a start boost, solid
state Positive Temperature Coefcient devices rated
from 10 to 25 ohms may be used to facilitate starting
for any of these compressors.
Electrical Connection
The orientation of the electrical connections on the
Copeland Scroll compressors is shown in Figure 4.
Three electrical connection options are available for
these compressors. These include the “Molded Plug”
one piece push-on connection, available in certain
markets, and “Quick Connect” ag termination available
on all scrolls of this size. Some four-ton and larger
models also offer “T-block Screw Connection” for ring
termination.
Deep Vacuum Operation
Scrolls incorporate internal low vacuum protection
and will stop pumping (unload) when the pressure
ratio exceeds approximately 10:1. There is an audible
increase in sound when the scrolls start unloading.
Copeland Scroll compressors (as with any refrigerant
compressor) should never be used to evacuate a
refrigeration or air conditioning system. The scroll
compressor can be used to pump down refrigerant in a
unit as long as the pressures remain within the operating
envelope shown in Figure 5. Prolonged operation at
low suction pressures will result in overheating of the
scrolls and permanent damage to the scroll tips, drive
bearings and internal seal. (See AE24-1105 for proper
system evacuation procedures.)
Nomenclature
The model numbers of the Copeland Scroll compressors
include the approximate nominal 60 HZ capacity at
standard operating conditions. An example would be the
ZR24K3-TFD, which has 24,500 Btu/hr (7 kw) cooling
capacity at the ARI high temperature air conditioning
rating point when operated on 60 Hz. Note that the
same compressor will have approximately 5/6 of this
capacity or 20,200 Btu/hr (5.9 kw) when operated on 50
Hz current. Please refer to Online Product Information
at www.emersonclimate.com for details.
Shell Temperature
Certain types of system failures, such as condenser
or evaporator fan blockage or loss of charge, may
cause the top shell and discharge line to briey but
repeatedly reach temperatures above 350ºF (177ºC)
as the compressor cycles on its internal protection
devices. Care must be taken to ensure that wiring or
other materials, which could be damaged by these
temperatures, do not come in contact with these
potentially hot areas.
Suction and Discharge Fittings
Copeland Scroll compressors have copper plated steel
suction and discharge ttings. These ttings are far
more rugged and less prone to leaks than copper ttings
used on other compressors. Due to the different thermal
properties of steel and copper, brazing procedures may
have to be changed from those commonly used. See
Figure 6 for assembly line and eld brazing procedures.
Three Phase Scroll Compressors
Scroll compressors, like several other types of
compressors, will only compress in one rotational
direction. Direction of rotation is not an issue with
single phase compressors since they will always start
and run in the proper direction (except as described in
the section “Brief Power Interruptions”). Three phase
compressors will rotate in either direction depending
upon phasing of the power. Since there is a 50-50
chance of connecting power in such a way as to cause
rotation in the reverse direction, it is important to
include notices and instructions in appropriate
locations on the equipment to ensure proper
rotation direction is achieved when the system
is installed and operated. Verification of proper
rotation direction is made by observing that suction
pressure drops and discharge pressure rises when the
compressor is energized. Reverse rotation will result
in substantially-reduced current draw compared to
normal values.

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There is no negative impact on durability caused by
operating three phase Copeland Scroll compressors in
the reversed direction for a short period of time (under
one hour) but oil may be lost. After several minutes of
reverse operation, the compressor’s internal protector
will trip. If allowed to repeatedly restart and run in
reverse without correcting the situation, the compressor
will be permanently damaged because of oil loss to
the system. Oil loss can be prevented during reverse
rotation if the tubing is routed at least six inches (15
cm) above the compressor. All three-phase scroll
compressors are wired identically internally. As a result,
once the correct phasing is determined for a specic
system or installation, connecting properly phased
power leads to the identied compressor electrical
(Fusite) terminals will maintain proper rotation direction.
See Fig 4. It should be noted that all three phase scrolls
will continue to run in reverse until the protector opens
or the phasing is corrected.
Brief Power Interruptions
Brief power interruptions (less than 1/2 second) may
result in powered reverse rotation of single-phase
Copeland Scroll compressors. This occurs because
high-pressure discharge gas expands backward through
the scrolls during power interruption, causing the scroll
to orbit in the reverse direction. When power is reapplied
while reverse rotation is occurring, the compressor may
continue to run in the reverse direction for some time
before the compressor’s internal protector trips. This
has no effect on durability. When the protector resets,
the compressor will start and run normally.
To avoid disruption of operation, an electronic control
that can sense brief power interruptions may be used
to lock out the compressor for a short time. This control
could be incorporated in other system controls (such
as defrost or thermostat), or be a stand-alone control.
Functional specications for this control as well as a
suggested wiring diagram are shown in Figure 3.
Because three-phase models have high enough torque
to prevent reverse rotation after power interruptions no
time delay is necessary.
ASSEMBLY LINE PROCEDURES
Installing the compressor
Scroll compressors leave the factory dehydrated with
a positive dry air charge. Plugs should not be removed
from the compressor until the compressor has had
sufcient time to warm up if stored outside and is ready
for assembly to the unit. It is suggested that the larger
suction plug be removed rst to relieve the internal
pressure. Removing the smaller discharge plug could
result in a spray of oil out of this tting since some oil
would accumulate in the head of the compressor after
Emerson test runs the compressor. The inside of both
ttings should we wiped with a lint free wipe to remove
residual oil prior to brazing. A compressor containing
mineral oil should never be left open longer than 15
minutes or 5 minutes if it contains POE oil.
Assembly Line Brazing Procedure
Figure 6 discusses the proper procedures for brazing
the suction and discharge lines to a scroll compressor.
It is important to ow nitrogen through the system
while brazing all joints during the system assembly
process. Nitrogen displaces the air and prevents the
formation of copper oxides in the system. If allowed
to form, the copper oxide akes can later be swept
through the system and block screens such as those
protecting capillary tubes, thermal expansion valves,
and accumulator oil return holes. The resulting
blockage of oil or refrigerant may do damage resulting
in compressor failure.
Pressure Testing
The pressure used on the line to meet the UL burst
pressure requirement can not be higher than 400 psig.
Higher pressure might result in permanent deformation
of the compressor shell and possibly cause rotor slip.
Assembly Line System Charging Procedure
Systems should be charged on both the high and low
sides simultaneously. The majority of the charge should
be placed in the high side of the system to prevent low
volt start difculties, Hipot failures, and bearing washout
during rst-time start on the assembly line. It is best to
charge only vapor into the low side of the system. Do
not operate compressor without enough system
charge to maintain at least 7 psig (0.5kg/cm2)
suction pressure. Do not operate with a restricted
suction. Do not operate with the low pressure cut-
out disabled. Allowing pressure to drop below 7 psig
(0.5 kg/cm2) for more than a few seconds may overheat
scrolls and cause early drive bearing damage. Do not
use compressor to test opening set point of a high
pressure cutout. Bearings are susceptible to damage
before they have had several hours of normal running
for proper break in.
“Hipot” (AC High Potential) Testing
Copeland Scroll compressors are congured with the
motor down and the pumping components at the top
of the shell. As a result, the motor can be immersed
in refrigerant to a greater extent than hermetic
reciprocating compressors when liquid refrigerant is
present in the shell. In this respect, the scroll is more like

AE4-1312 R2
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semi-hermetic compressors which can have horizontal
motors partially submerged in oil and refrigerant. When
Copeland Scroll compressors are Hipot tested with liquid
refrigerant in the shell, they can show higher levels of
leakage current than compressors with the motor on top.
This phenomenon can occur with any compressor when
the motor is immersed in refrigerant. The level of current
leakage does not present any safety issue. To lower the
current leakage reading, the system should be operated
for a brief period of time to redistribute the refrigerant
to a more normal conguration and the system Hipot
tested again. See AE Bulletin 4-1294 for Megohm testing
recommendations. Under no circumstances should the
Hipot test be performed while the compressor is under
a vacuum.
Final Run Test
Single phase scrolls with an electrical characteristic of
“PFV” (208-230 volt, 1Ô, 60 Hertz) at the end of the
model number may not be started at a voltage lower
than 187 volts and must have a voltage no lower than
197 volts once the compressor is running under load.
Variable transformers used on assembly lines are often
not capable of starting larger compressors at a particular
voltage setting. To test for voltage sag during the initial
locked rotor starting phase the rst compressor in a
production run should be used to preset the voltage.
Remove the start wire from the compressor and apply
200 volts to the compressor. With the start winding
removed the compressor will remain in locked rotor long
enough to read the voltage supply. If the voltage sags
below the minimum guaranteed starting voltage the
variable transformer must be preset to a higher voltage
to start the compressor at a higher voltage.
Other compressor voltages. All other compressor
voltages, both single and three phase are guaranteed
to start and run at 10% below the lowest voltage shown
on the nameplate.
Unbrazing System Components
Caution! Before opening a system it is important
to remove all refrigerant from both the high and
low side. If the refrigerant charge is removed from a
scroll-equipped unit by bleeding one side only, it is very
possible that either the high or low side of the system
remains pressurized. If a brazing torch is then used
to disconnect tubing, the pressurized refrigerant and
oil mixture could ignite when it escapes and contacts
the brazing ame. It is important to check both the
high pressure and low pressure side with manifold
gauges before unbrazing. Instructions should be
provided in appropriate product literature and assembly
(line repair) areas. If compressor removal is required,
the compressor should be cut out of system rather
than unbrazed. See Figure 6 for proper compressor
removal procedure.
Copeland Scroll Functional Check
A functional compressor test during which the suction
service valve is closed to check how low the compressor
will pull suction pressure is not a good indication of
how well a compressor is performing. Such a test will
damage a scroll compressor. The following diagnostic
procedure should be used to evaluate whether a
Copeland Scroll compressor is functioning properly:
1. Proper voltage to the unit should be verified.
Determine if the internal motor overload protector
has opened or if an internal motor short or ground
fault has developed. If the protector has opened,
the compressor must be allowed to cool sufciently
to allow it to reset.
2. Check that the compressor is correctly wired.
3. Proper indoor and outdoor fan/blower operation
should be veried.
4. With service gauges connected to suction and
discharge pressure ttings, turn on the compressor.
If suction pressure falls below normal levels the
system is either low on charge or there is a ow
blockage in the system.
5. Single Phase Compressors
If the compressor starts and the suction pressure
does not drop and discharge pressure does not rise
to normal levels, either the reversing valve (if so
equipped) or the compressor is faulty. Use normal
diagnostic procedures to check operation of the
reversing valve.
Three Phase Compressors
If suction pressure does not drop and discharge
pressure does not rise to normal levels, reverse
any two of the compressor power leads and reapply
power to make sure the compressor was not wired
to run in reverse. If pressures still do not move
to normal values, either the reversing valve (if so
equipped) or the compressor is faulty. Reconnect
the compressor leads as originally configured
and use normal diagnostic procedures to check
operation of the reversing valve.
6. To test if the compressor is pumping properly, the
compressor current draw must be compared to
published compressor performance curves using
the operating pressures and voltage of the system.
If the measured average current deviates more than
±15% from published values, a faulty compressor
may be indicated. A current imbalance exceeding

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8
15% of the average on the three phases of a three-
phase compressor should be investigated further. A
more comprehensive trouble-shooting sequence for
compressors and systems can be found in Section
H of the Emerson Climate Technologies Electrical
Handbook.
7. Before replacing or returning a compressor:Be
certain that the compressor is actually defective. As
a minimum, recheck a compressor returned from
the eld in the shop or depot for Hipot, winding
resistance, and ability to start before returning to
Emerson Climate Technologies. More than one-third
of compressors returned to Emerson for warranty
analysis are determined to have nothing found
wrong. They were misdiagnosed in the eld as
being defective. Replacing working compressors
unnecessarily costs everyone.
Tandem Scroll Compressors
The refrigerant charge limit for tandem compressors
is shown in Table 5. A three-phase unit with a charge
over this limit must have crankcase heaters added to
both compressors. The ZRT90 – ZRT122 compressors
are mounted on rails using rubber mounting parts. The
ZRT136 – ZRT162 compressors are rigidly mounted
on rails using solid steel mounting parts. These
mounts are installed at the factory and should not be
loosened. Tighten to 125 inch pounds (14 NM) if it
becomes necessary to tighten these mounts. Holes
in the mounting rails may be used to mount isolation
grommets under the entire tandem.
A discharge check valve must be placed in the
common discharge line when pump down is used. Both
compressors must be at the same level to prevent oil
from migrating to the lowest compressor through the
oil equalization line.
Compressors may be individually cycled. Individual
compressors should not be replaced in the eld. The
entire tandem compressor unit must be replaced if
it becomes necessary to replace one compressor.
Individual compressors congured for tandem usage
may not be available for field replacement. See
section below for further tips on eld replacement of
compressors.
Compressor Replacement after Motor Burn
In the case of a motor burn, the majority of contaminated
oil will be removed with the compressor. The rest of the
oil is cleaned through use of suction and liquid line lter
dryers. A 100% activated alumina suction lter drier is
recommended but must be removed after 72 hours. See
AE24-1105 for clean up procedures and AE11-1297
for liquid line lter-drier recommendations. It is highly
recommended that the suction accumulator be
replaced if the system contains one. This is because
the accumulator oil return orice or screen may be
plugged with debris or may become plugged shortly after
a compressor failure. This will result in starvation of oil
to the replacement compressor and a second failure.
Start-up of a New or Replacement Compressor
It is good service practice, when charging a system,
to charge liquid refrigerant into the high side only and
charge the low side of the system with vapor only. It is
not good for any compressor to have liquid refrigerant
dumped from a refrigerant cylinder into the crankcase
of the compressor. Do not start the compressor while
the system is in a deep vacuum. Internal arcing may
occur when a scroll compressor is started in a vacuum.
Do not operate compressor without enough system
charge to maintain at least 7 psig (0.5 kg/cm2)
suction pressure. Do not operate with a restricted
suction. Do not operate with the low pressure
cut-out disabled. Allowing suction pressure to drop
below 7 psig (0.5 kg/cm2) for more than a few seconds
may overheat scrolls and cause early drive bearing
damage. Never install a system in the eld and leave it
unattended with no charge, a holding charge, or with the
service valves closed without securely locking out the
system. This will prevent unauthorized personnel from
accidentally operating the system for comfort cooling
and potentially ruining the compressor by operating
with no refrigerant ow.
Excessive Liquid Flood back Tests
The following tests are for those system congurations
and charge levels identied in Table 1 that need special
testing to verify exemption from need of an accumulator.
Figure 1 should be used to determine the effectiveness
of an accumulator. The compressor sump temperature
during any test where the return gas superheat is near
zero must always meet the guidelines of Figure 1.
To test for excessive continuous liquid refrigerant
ood back, it is necessary to operate the system in a test
room at conditions where steady state ood back may
occur (low ambient heating operation). Thermocouples
should be attached with glue or solder to the center of
the bottom shell and to the suction and discharge lines
approximately 6 inches (15 cm from the shell). These
thermocouples should be insulated from the ambient air
with Permagum®or other thermal insulation to be able
to record true shell and line temperatures. If the system
is designed to be eld charged, it should be overcharged
by 15% in this test to simulate overcharging commonly
found in eld installations.

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The system should be operated at an indoor temperature
of 70°F (21°C). and outdoor temperature extremes (0°F
or -18°C or lower in heating) to produce ood back
conditions. The compressor suction and discharge
pressures and temperatures as well as the sump
temperature should be recorded. The system should
be allowed to frost up for several hours (disabling the
defrost control and spraying water on the outdoor coil
may be necessary) to cause the saturated suction
temperature to fall to below -10°F (-23°C). The
compressor sump temperature must remain above the
sump temperature shown in Figure 1 or design changes
must be made to reduce the amount of ood back. If an
accumulator is used, an oil return orice size of 0.040
- .055” (1 - 1.4 mm) is recommended. (See information
on Accumulators in Application Considerations and also
AE11-1247). Increasing indoor coil volume, increasing
outdoor air ow, reducing refrigerant charge, decreasing
capillary or orifice diameter, and adding a charge
compensator can also be used to reduce excessive
continuous liquid refrigerant ood back.
To test for repeated excessive liquid ood back
during normal system off-cycles perform the “Field
Application Test”. Obtain a sample compressor
with a side sight tube to measure liquid level in the
compressor. Set the system up in a conguration with
the indoor unit elevated several feet above the outdoor
unit with twenty-five feet (8 meters) of connecting
tubing with no traps between the indoor and outdoor
units. If the system is designed to be eld charged,
the system should be overcharged by 15% in this
test to simulate overcharging commonly found in eld
installations. Operate the system in the cooling mode
at the outdoor ambient, on/off cycle times, and number
of cycles specied in Table 2. Record the height of the
liquid in the compressor at the start of each on cycle,
any protector trips, or any compressor stalls during
each test. Review the results with Emerson Climate
Technologies Application Engineering to determine
if an accumulator is required for the application. The
criteria for pass/fail is whether the liquid level reaches
the height of the scroll compressor suction tting on the
side of the shell. Liquid levels higher than the suction
tting will allow compressor oil oating on top of the
refrigerant to be ingested by the scrolls and pumped
out of the compressor.

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10
Oil Dilution Chart
0
10
20
30
40
50
60
70
80
90
100
-100 10 20 30 40 50
Evaporating Temperature °F
Compressor Sump Temperatur
e
°F
Safe Area OK. See Note 1
Unsafe Area. Too Much Refrigerant Dilution
200°F Maximum Oil Temperature
Figure 1
Figure 1
Note 1: Operation in this refrigerant dilution area is safe in air to air heat pump heating mode. For
other applications, such as AC only, review expansion device to raise superheat. A cold sump may
result in high refrigerant migration after shut down.
Liquid
Level
Drainage
In Off
Cycle
Scroll Accumulator
Figure 2
To prevent ooded start damage on 3 phase scrolls due to off cycle migration, the accumulator may be
congured on some systems to allow free drainage from the compressor to the accumulator during the
off cycle. When the above conguration is not possible and the unit charge is over the charge limit shown
in Table 5, a crankcase heater is required.

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Figure 3
Note: Wire A-B
is NOTrequired
when optional
timer is used
Time Delay Relay Specifications
Timer Opens1Electrical cycleTimer Closes Greater than 5 seconds later
(.016 sec. with 60 HZ operation) power is restored or not
after power is removed
Typical Solid State Timer
(if used)
Fuse
Discharge Line
Thermostat (if used)Compressor Contactor
Condenser Fan Contactor
(if used)
Other Protective
Devices (if used)
System Operating
Thermostat
230/240 VAC
C1
C

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T1,C
T2,S
T3,R
Motor Terminal (Fusite) Connections
Figure 4
Terminal (Fusite) Connection
70
80
90
100
110
120
130
140
150
160
170
-20-10 0102030405060
Condensing Temp. (°C)
Evaporating Temp. (°C)
Condensing Temp. (°F)
Evaporating Temp. (°F)
R22 Scroll Operating Envelope
-20-15-10-50510
-2515
70
60
50
40
30
ZR__KA
Limited
Envelope
All Other Scroll Products
Figure 5

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New Installations
• The copper-coated steel suction tube on scroll
compressors can be brazed in approximately
the same manner as any copper tube.
• Recommended brazing materials: Any silfos
material is recommended, preferable with a
minimum of 5% silver. However, 0% silver is
acceptable.
• Be sure suction tube tting I.D. and suction
tube O.D. are clean prior to assembly. If oil lm
is present wipe with denatured alcohol, Dichlo-
ro-Triuoroethane or other suitable solvent.
• Using a double-tipped torch apply heat in Area
1. As tube approaches brazing temperature,
move torch ame to Area 2.
• Heat Area 2 until braze temperature is attained,
moving torch up and down and rotating around
tube as necessary to heat tube evenly. Add
braze material to the joint while moving torch
around joint to ow braze material around cir-
cumference.
• After braze material ows around joint, move
torch to heat Area 3. This will draw the braze
material down into the joint. The time spent
heating Area 3 should be minimal.
• As with any brazed joint, overheating may be
detrimental to the nal result.
Field Service
• To disconnect: Reclaim refrigerant from both
the high and low side of the system. Cut tub-
ing near compressor.
• To reconnect:
• Recommended brazing materials:
Silfos with minimum 5% silver or
silver braze material with ux.
• Insert tubing stubs into tting and
connect to the system with tubing
connectors.
• Follow New Installation brazing
instructions.
Figure 6
}
}
}
1
2
3
Scroll Suction Tube Brazing

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Operating Principle of Scroll
Figure 7

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Non-Bleed
TXV
Non-Bleed
TXV
Other (1)
Other (1)
Not
Required
Not
Required
Other (1)
Required
Required Not
Required
Not
Required Required
Not
Required
Required
Required Not
Required
Required
Required
Required
Other (1)
Nominal
System
Charage
(2)
Table 1
Scroll Compressor Application Diagram
(1) “Other” includes bleed-type TXVs, capillary tubes, and xed orices. (2) “Nominal System Charge” is dened as the design charge for a system. Note: See text for crankcase heater requirements. *120% Times Compressor refrigerant charge limit in Table 5.
**
*
*
*
*
*
*
*
*
*

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Table 2
Field Application Test
Operate the system as it would be operated in an actual eld installation, cycling the
unit on and off for the times indicated at each ambient.
Outdoor Ambient 85°F (29°C) 95°F (35°C) 105°F (40°C)
System On-Time (Minutes) 7 14 54
System Off-Time (Minutes) 13 8 6
Number of On/Off Cycles 5 5 4
Recommended Conguration
Component Description
Tubing Conguration Shock loop
Service Valve “Angled valve” fastened to unit
Suction mufer Not required
Alternate Conguration
Component Description
Tubing Conguration Shock loop
Service Valve “Straight through” valve not fastened to unit
Suction mufer May be required (Acts as dampening mass)
Table 3
K1 *K2 K3 K4 KC
ZR18 25µf/370 volt 30µf/370 volt 35µf/370 volt 30µf/370 volt
ZR23 30µf/370 volt 40µf/370 volt 35µf/370 volt 35µf/370 volt
ZR26 35µf/370 volt 40µf/370 volt 30µf/440 volt
ZR28 35µf/370 volt 45µf/370 volt 35µf/440 volt
ZR34 35µf/440 volt 50µf/370 volt 40µf/370 volt
ZR40 35µf/440 volt 55µf/370 volt 40µf/440 volt
ZR46 40µf/440 volt 60µf/370 volt
ZR49 40µf/440 volt 60µf/370 volt 45µf/440 volt
ZR57 55µf/440 volt 80µf/370 volt 60µf/370 volt
ZR61 55µf/440 volt 80µf/370 volt 60µf/370 volt
Table 4
Recommended Run Capacitors for Field Replacement
of a ZR*K1 or K2 with a ZR*K3, K4, or KC

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Model Frame Size* Charge Limit 120% x Limit **
Pounds kg Pounds kg
ZR16-ZR29KC 53 6 2.7 7.2 3.24
ZR16-ZR24K4 53 6 2.7 7.2 3.24
ZR26-ZR48KC 63 8 3.6 9.6 4.32
ZR18-ZR48K3 63 8 3.6 9.6 4.32
ZR54-ZR81KC 70 10 4.5 12.0 5.40
ZR54-ZR61K3 70 10 4.5 12.0 5.40
ZR16-ZR34KA 53 8 3.6 9.6 4.32
ZR38-ZR54KA 63 10 4.5 12.0 5.40
TANDEM 63 10 4.5 12.0 5.40
TANDEM 70 12 5.5 14.4 6.60
Table 5
Compressor Refrigerant Charge Limits
*Approximate Shell Diameter (e.g. 63 = 6.5 Inches)
** Charge Allowance for system
Table 6
Crankcase Heaters
Copeland®Model Frame
Size Emerson Part # Volts Watts Tutco Part # Leads
ZR16KC/4 - ZR29KC/4
ZR16KA - ZR34KA
53 018-0052-00 240 40 02-6319-00 21”
53 018-0052-01 120 40 02-6319-02 21”
ZR18K3 - ZR48K3
ZR26KC - ZR48KC
ZR38KA - ZR54KA
63 018-0041-00 240 40 02-6307-00 21”
63 018-0041-01 120 40 02-6307-02 21”
63 018-0041-02 480 40 02-6307-03 21”
63 018-0041-03 575 40 02-6307-06 21”
63 018-0041-04 240 40 02-6311-00 48”
63 018-0041-05 480 40 02-6311-03 48”
63 018-0041-06 240 40 02-6313-00 32”
ZR54K3 - ZR61K3
ZR54K3 - ZR81KC
All 018-0057-XX
Heaters t both 63 and
70 frame* shells
70 018-0057-00 240 70 02-6332-00 21”
70 018-0057-01 480 70 02-6332-03 21”
70 018-0057-02 575 70 02-6332-06 21”
63 & 70
018-0057-03 240 70 02-6334-00 32”
018-0057-04 240 70 02-6335-00 48”
018-0057-05 480 70 02-6335-03 48”
018-0057-06 575 70 02-6335-06 48”
018-0057-07 120 70 02-6335-02 48”
018-0057-08 400 70 02-6335-12 48”
018-0057-09 277 70 02-6332-04 21”
*Approximate Shell Diameter (e.g. 70 = 7.3 Inches)

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Table 7
Approved Start Components for Scroll Compressors
Model MFD Volts Part
Number G.E. p/n Emerson p/n Pick-up Volts
Drop-out
Volts
Coil
Voltage
ZR16K(x) to
ZR48K(x)-PFV 88-108 330 014-0036-03 3ARR3CT3P5 040-0001-79 170-180 40-90 332
ZR46K(x) to
ZR68K(x)-PFV 270-324 330 014-0006-10 3ARR3CT3P5 040-0001-79 170-180 40-90 332
x = C, 3, 4 or CE, 3E, 4E (ZR_KA Start components still in development)