Emerson Copeland Scroll ZR24KRE Instruction Manual

Copeland Scroll™ Compressors for
comfort, precision and process cooling
ZR24KRE to ZR92KRE
Application Guidelines

C6.2.41/0219/E
About these guidelines ...............................................................................................1
1Safety instructions...........................................................................................1
1.1 Icon explanation............................................................................................................... 1
1.2 Safety statements............................................................................................................ 1
1.3 General instructions......................................................................................................... 2
2Product description .........................................................................................3
2.1 Common information about Copeland Scroll™ compressors.......................................... 3
2.2 Nomenclature................................................................................................................... 3
2.3 BOM Variation.................................................................................................................. 3
2.4 Dimensions ...................................................................................................................... 4
2.5 Application range ............................................................................................................. 7
2.5.1 Qualified refrigerants and oils .............................................................................. 7
2.5.2 Application limits................................................................................................... 7
3Installation........................................................................................................8
3.1 Compressor handling....................................................................................................... 8
3.1.1 Transport and storage.......................................................................................... 8
3.1.2 Positioning and securing...................................................................................... 8
3.1.3 Installation location............................................................................................... 8
3.1.4 Mounting parts...................................................................................................... 8
3.2 Brazing procedure............................................................................................................ 9
3.3 Shut-off valves and adaptors......................................................................................... 10
3.4 Suction accumulators..................................................................................................... 10
3.5 Screens.......................................................................................................................... 11
3.6 Mufflers .......................................................................................................................... 11
3.7 Suction line noise and vibration..................................................................................... 11
4Electrical connection .....................................................................................13
4.1 General recommendations............................................................................................. 13
4.2 Electrical installation ...................................................................................................... 13
4.2.1 Terminal box....................................................................................................... 15
4.2.2 Motor windings ................................................................................................... 15
4.2.3 Protection devices.............................................................................................. 15
4.2.4 Crankcase heaters ............................................................................................. 15
4.3 Pressure safety controls ................................................................................................ 16
4.3.1 High-pressure control......................................................................................... 16
4.3.2 Low-pressure control.......................................................................................... 16
4.3.3 Internal pressure relief valve.............................................................................. 16
4.4 Discharge temperature protection ................................................................................. 16
4.5 High-potential testing ..................................................................................................... 17
5Starting up & operation..................................................................................18
5.1 Strength pressure test.................................................................................................... 18

C6.2.41/0219/E
5.2 Tightness/pressure test.................................................................................................. 18
5.3 System evacuation......................................................................................................... 18
5.4 Preliminary checks –Pre-starting.................................................................................. 18
5.5 Charging procedure ....................................................................................................... 19
5.6 Initial start-up ................................................................................................................. 19
5.7 Rotation direction........................................................................................................... 19
5.8 Starting sound................................................................................................................ 20
5.9 Deep vacuum operation................................................................................................. 20
5.10 Shell temperature........................................................................................................... 20
5.11 Pump-down cycle........................................................................................................... 20
5.12 Minimum run time .......................................................................................................... 20
5.13 Shut-off sound................................................................................................................ 21
5.14 Frequency...................................................................................................................... 21
5.15 Oil level .......................................................................................................................... 21
6Maintenance & repair.....................................................................................22
6.1 Exchanging the refrigerant............................................................................................. 22
6.2 Rotalock valves.............................................................................................................. 22
6.3 Replacing a compressor................................................................................................ 22
6.3.1 Compressor replacement................................................................................... 22
6.3.2 Start-up of a new or replacement compressor................................................... 22
6.4 Lubrication and oil removal............................................................................................ 23
6.5 Oil additives ................................................................................................................... 23
6.6 Unbrazing system components ..................................................................................... 23
7Dismantling & disposal..................................................................................24
DISCLAIMER ..............................................................................................................24

C6.2.41/0219/E 1
About these guidelines
The purpose of these application guidelines is to provide guidance in the application of Copeland
Scroll™ compressors in users’ systems. They are intended to answer the questions raised while
designing, assembling and operating a system with these products.
Besides the support they provide, the instructions listed herein are also critical for the proper and
safe functioning of the compressors. Emerson will not guarantee the performance and reliability
of the product if it is misused in regard of these guidelines.
These application guidelines cover stationary applications only. For mobile applications, contact
Application Engineering as other considerations may apply.
1 Safety instructions
Copeland Scroll™compressors are manufactered according to the latest European and US Safety
Standards. Particular emphasis has been placed on the user’s safety.
These compressors are intended for installation in systems in accordance with the Machinery
Directive MD 2006/42/EC and the Pressure Equipment Directive PED 2014/68/EU. They may be
put to service only if they have been installed in these systems according to instructions and
conform to the corresponding provisions of legislation. For relevant standards please refer to
Manufacturers Declaration, available at www.climate.emerson.com/en-gb.
These instructions should be retained throughout the lifetime of the compressor.
You are strongly advised to follow these safety instructions.
1.1 Icon explanation
WARNING
This icon indicates instructions to
avoid personal injury and material
damage.
CAUTION
This icon indicates instructions to
avoid property damage and possible
personal injury.
High voltage
This icon indicates operations with a
danger of electric shock.
IMPORTANT
This icon indicates instructions to
avoid malfunction of the compressor.
Danger of burning or frostbite
This icon indicates operations with a
danger of burning or frostbite.
NOTE
This word indicates a
recommendation for easier operation.
Explosion hazard
This icon indicates operations with a
danger of explosion.
1.2 Safety statements
▪Refrigerant compressors must be employed only for their intended use.
▪Only qualified and authorized HVAC or refrigeration personnel are permitted to install,
commission and maintain this equipment.
▪Electrical connections must be made by qualified electrical personnel.
▪All valid standards for connecting electrical and refrigeration equipment must be
observed.
▪The national legislation and regulations regarding personnel protection must be
observed.
Use personal safety equipment. Safety goggles, gloves,
protective clothing, safety boots and hard hats should be worn
where necessary.

2 C6.2.41/0219/E
1.3 General instructions
WARNING
System breakdown! Personal injuries! Never install a system in the field
and leave it unattended when it has no charge, a holding charge, or with the
service valves closed without electrically locking out the system.
System breakdown! Personal injuries! Only approved refrigerants and
refrigeration oils must be used.
WARNING
High shell temperature! Burning! Do not touch the compressor until it has
cooled down. Ensure that other materials in the area of the compressor do not
get in touch with it. Lock and mark accessible sections.
CAUTION
Overheating! Bearing damage! Do not operate compressors without
refrigerant charge or without being connected to the system.
CAUTION
Contact with POE! Material damage! POE lubricant must be handled
carefully and the proper protective equipment (gloves, eye protection, etc.)
must be used at all times. POE must not come into contact with any surface
or material that it might damage, including without limitation, certain polymers,
eg, PVC/CPVC and polycarbonate.
IMPORTANT
Transit damage! Compressor malfunction! Use original packaging. Avoid
collisions and tilting.

C6.2.41/0219/E 3
2 Product description
2.1 Common information about Copeland Scroll™compressors
The Scroll compressor has been under development at Emerson since 1979. It is the most efficient
and durable compressor Emerson has ever developed.
These application guidelines deal with all vertical single Copeland scroll compressors for
air-conditioning applications from ZR24KRE to ZR92KRE.
Compressor
Cooling capacity [kW]
Motor
R450A
R513A
ZR24KRE
1.64
1.94
PFJ/TFD
ZR28KRE
1.94
2.36
PFJ/TFD
ZR36KRE
2.52
3.05
PFJ/TFD
ZR42KRE
2.91
3.43
PFJ/TFD
ZR48KRE
3.31
3.89
TFD
ZR61KRE
4.26
5.03
TFD
ZR69KRE
4.82
5.70
PFJ
ZR72KRE
5.01
5.92
TFD
ZR81KRE
5.62
6.59
TFD
ZR92KRE
6.24
7.52
TFD
Table 1: Cooling capacity for medium temperature compressors @ -10°C/45°C/10K/0K
Copeland Scroll compressors have one Scroll compression set driven by a single or three-phase
induction motor. The Scroll set is mounted at the upper end of the rotor shaft of the motor. The
rotor shaft axis is in the vertical plane.
2.2 Nomenclature
The model designation contains the following technical information about the standard and vapour
injection compressors:
2.3 BOM Variation
The BOM (bill of material) number at the end of the compressor designation indicates the
compressor layout and details. In general, there is one BOM version for the complete ZR*KRE
compressor range:
BOM 455 braze connections, oil sight glass, oil service connection, IP21 t-box, no mounting
parts
Please refer to the Emerson price list for more details.

4 C6.2.41/0219/E
2.4 Dimensions
Compressor
model
A
[mm]
B
[mm]
C
[mm]
D
[mm]
E
[mm]
F
[mm]
ØG
[mm]
ØH
[mm]
ZR24/28KRE
364.1
338.5
202.9
69.6
43.7
244.5
12.78-12.95
19.12-19.30
ZR36KRE
386.7
361.1
222.8
75.3
49.4
264.4
12.78-12.95
19.12-19.30
ZR42KRE
400.4
374.9
235.5
75.3
49.4
277.1
12.78-12.95
19.12-19.30
ZR48KRE
417.4
391.9
252.5
75.3
49.4
294.1
12.78-12.95
22.30-22.48
ZR61/69/72KRE
434.9-440.8
409.6
230.2-236.2
79.6
47.6
296.7
12.78-12.95
22.30-22.48
ZR81/92KRE
434.9-440.8
409.6
230.2-236.2
79.6
47.6
296.7
19.12-19.30
22.30-22.48
Table 2: Dimensions Scroll ZR*KRE
Figure 1: Dimensions for models ZR24KRE to ZR48KRE

C6.2.41/0219/E 5
Figure 2: Dimensions for models ZR61KRE to ZR72KRE

6 C6.2.41/0219/E
Figure 3: Dimensions for models ZR81KRE to ZR92KRE

C6.2.41/0219/E 7
2.5 Application range
2.5.1 Qualified refrigerants and oils
IMPORTANT
It is essential that the glide of refrigerant blends (primarily R450A) be carefully
considered when adjusting pressure and superheat controls.
Oil recharge values can be taken from Copeland Scroll compressors brochures or Copeland™
brand products Select software available at www.climate.emerson.com/en-gb.
Compressor
ZR*KRE
Qualified refrigerants
R450A, R513A
Copeland™ brand products
standard oil
Emkarate RL 32 3MAF
Servicing oils
Emkarate RL 32 3MAF, Mobil EAL Arctic 22 CC
Table 3: Qualified refrigerants and oils
2.5.2 Application limits
CAUTION
Inadequate lubrication! Compressor breakdown! The superheat at the
compressor suction inlet must always be sufficient to ensure that no refrigerant
droplets enter the compressor. For a typical evaporator-expansion valve
configuration a minimum stable superheat of at least 5K is required.
Application envelopes for the various refrigerants can be found in Select software, available at
www.climate.emerson.com/en-gb.

8 C6.2.41/0219/E
3 Installation
WARNING
High pressure! Injury to skin and eyes possible! Be careful when opening
connections on a pressurized item.
3.1 Compressor handling
3.1.1 Transport and storage
WARNING
Risk of collapse! Personal injuries! Move compressors only with
appropriate mechanical or handling equipment according to weight. Keep in
the upright position. Respect stacking loads according to Figure 4. Check the
tilting stability and if needed take action to ensure the stability of the stacked
loads. Keep the packaging dry at all times.
Respect the maximum number of identical packages which may be stacked on one
another, where "n" is the limiting number:
▪Transport: n = 1
▪Storage: n = 2
Figure 4: Maximum stacking loads for transport and storage
The compressor tilt angle should not be more than 30° during transport and handling. This will
prevent oil from exiting through the suction stub. A tilt angle of maximum 45° is allowed for a
very short time. Tilting the compressor more than 45° might affect its lubrication at start-up.
3.1.2 Positioning and securing
IMPORTANT
Handling damage! Compressor malfunction! Only use the lifting eyes
whenever the compressor requires positioning. Using discharge or suction
connections for lifting may cause damage or leaks.
If possible, the compressor should be kept vertical during handling.
The discharge connection plug should be removed first before pulling the suction connection plug
to allow the dry air pressure inside the compressor to escape. Pulling the plugs in this sequence
prevents oil mist from coating the suction tube making brazing difficult. The copper-coated steel
suction tube should be cleaned before brazing.
The compressor plugs must be removed as late as possible before brazing so that the air humidity
does not affect the oil characteristics.
No object, eg, a swaging tool should be inserted deeper than 51 mm into the suction tube as it
might damage the suction screen and motor.
3.1.3 Installation location
Scroll compressors are capable of operating correctly with compressor ambient humidity between
30% and 95%. For correct operation the compressor ambient air temperatures have to be between
-40°C and 60°C and the compressor PS and TS have to be respected at all times during operation
and at a standstill.
Ensure the compressors are installed on a solid level base. For single compressor application, the
compressor tilt angle during operation should not be more than 15° to allow adequate lubrication.
For multiple compressor parallel configurations, the compressors must be positioned completely
vertically on a totally horizontal surface or rail.
3.1.4 Mounting parts
A kit of vibration absorber grommets can be ordered with each compressor. They dampen the
start-up surge of the compressor and minimise sound and vibration transmission to the
compressor base during operation. The metal sleeve inside is a guide designed to hold the

C6.2.41/0219/E 9
grommet in place. It is not designed as a load-bearing member, and application of excessive
torque to the bolts can crush the sleeve. Its inner diameter is approximately 8.5 mm to fit, eg, an
M8 screw. The mounting torque should be 13 ± 1 Nm. It is critically important for the grommet not
to be compressed.
If the compressors are mounted in tandem or used in parallel, then the hard mountings (bolt M9
5/16") are recommended. The mounting torque should be 27 ± 1 Nm. It is possible to deliver these
hard mounting parts as a kit. See Emerson spare parts software for reference.
Mounting parts: ZR24K* to ZR92K* - Soft mountings
Figure 5: Mounting parts
3.2 Brazing procedure
IMPORTANT
Blockage! Compressor breakdown! Maintain a flow of oxygen-free nitrogen
through the system at very low pressure during brazing. Nitrogen displaces
the air and prevents the formation of copper oxides in the system. If allowed
to form, the copper oxide material can later be swept through the system and
block screens such as those protecting capillary tubes, thermal expansion
valves, and accumulator oil return holes.
Contamination or moisture! Bearing failure! Do not remove the plugs until
the compressor is set into the unit. This minimises any entry of contaminants
and moisture.
Copeland Scroll compressors have copper-plated steel
suction and discharge tubes. These tubes are far more
robust and less prone to leaks than copper tubes. Due to
the different thermal properties of steel and copper,
brazing procedures may have to be changed from those
commonly used.
Refer to Figure 6 and the procedure below for the
brazing of the suction and discharge lines to a scroll
compressor.
▪The copper-coated steel tubes on Scroll compressors can be brazed in approximately the
same manner as any copper tube.
▪Recommended brazing materials: any silfos material is recommended, preferably with a
minimum of 5% silver. However, 0% silver is acceptable.
▪Be sure tube fitting inner diameter and tube outer diameter are clean prior to assembly.
▪Using a double-tipped torch, apply heat in area 1.
▪As the tube approaches brazing temperature, move the torch flame to area 2.
▪Heat area 2 until braze temperature is attained, moving the torch up and down and rotating
around the tube as necessary to heat the tube evenly. Add braze material to the joint while
moving the torch around the joint to flow braze material around the circumference.
▪After the braze material flows around the joint, move the 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 final result.
To disconnect:
▪Heat joint areas 2 and 3 slowly and uniformly until the braze material softens and the tube can
be pulled out of the fitting.
To reconnect:
▪Recommended brazing materials: Silfos with minimum 5% silver or silver braze 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.
Figure 6: Suction tube brazing areas

10 C6.2.41/0219/E
NOTE: Since the discharge stub contains a check valve, care must be taken not to overheat
it to prevent brazing material from flowing into it.
3.3 Shut-off valves and adaptors
CAUTION
Leaking system! System breakdown! It is strongly recommended to
periodically re-torque all pipe and fixing connections to the original setting after
the system has been put into operation.
Figure 7
Copeland Scroll compressors ZR*KRE are delivered with a discharge check valve fitted inside the
discharge port and stub tubes as standard. There are options to fit Rotalock adaptors and Rotalock
valves.
Brazing connections can be converted to Rotalock by means of adaptors. Rotalock shut-off valves
are available for the suction as well as discharge sides. Using either straight or angled adaptors
provides a way to convert a Rotalock into a brazing connection.
Refer to the following table for proper tightening torques:
Torque [Nm]
Rotalock ¾" –16UNF
40-50
Rotalock 1" –14UNS
70-80
Rotalock 1 ¼" –12UNF
110-135
Rotalock 1 ¾" –12UNF
135-160
Rotalock 2 ¼" –12UNF
165-190
Table 4
NOTE: More information about adaptors and shut-off valves can be found in the spare parts
software at www.climate.emerson.com/en-gb.
3.4 Suction accumulators
CAUTION
Inadequate lubrication! Bearing destruction! Minimise liquid refrigerant
returning to the compressor. Too much refrigerant dilutes the oil. Liquid
refrigerant can wash the oil off the bearings leading to overheating and bearing
failure.
Irrespective of system charge, oil dilution may occur if large amounts of liquid refrigerant
repeatedly flood back to the compressor during:
▪normal off cycles;
▪defrost;
▪varying loads.

C6.2.41/0219/E 11
In such a case an accumulator must be used to reduce flood-back to a safe level that the
compressor can handle. The use of accumulators is dependent on the application. If an
accumulator must be used, the oil-return orifice should be from 1 to 1.4 mm in diameter for all
ZR*KRE models, depending on compressor size and compressor flood-back results.
The size of the accumulator depends upon the operating range of the system and the amount of
subcooling and subsequent head pressure allowed by the refrigerant control.
3.5 Screens
CAUTION
Screen blocking! Compressor breakdown! Use screens with at least
0.6 mm openings.
The use of screens finer than 30 x 30 mesh (0.6 mm openings) anywhere in the system should be
avoided with these compressors. Field experience has shown that finer 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 flow of either oil or refrigerant to
the compressor. Such blockage can result in compressor failure.
3.6 Mufflers
External mufflers, normally applied to piston compressors in the past, may not be required for
Copeland Scroll compressors.
Individual system tests should be performed to verify acceptability of sound performance. If
adequate attenuation is not achieved, use a muffler with a larger cross-sectional area to inlet area
ratio. A ratio of 20:1 to 30:1 is recommended.
A hollow shell muffler will work quite well. Locate the muffler at minimum 15 to maximum 45 cm
from the compressor for the most effective operation. The further the muffler is placed from the
compressor within these ranges, the more effective. Choose a muffler with a length of 10 to
15 cm.
3.7 Suction line noise and vibration
Copeland Scroll compressors inherently have low
sound and vibration characteristics. However in
some respects the sound and vibration
characteristics differ from reciprocating compressors
and in rare instances could result in unexpected
sound generation. One differenceis 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" frequencythat can be
detected as noise coming along the suction line into
the building under some conditions. Elimination of
the beat can be achieved by attenuating either of the
contributing frequencies. This is easily done by using
one of the common combinations of recommended design configurations. The scroll compressor
makes both a rocking and twisting motion and enough flexibility 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 below.
Figure 8: Suction tube design

12 C6.2.41/0219/E
Recommended configuration
▪Tubing configuration: ...........small shock loop
▪Service valve: ....................."angled”valve fastened to unit / wall
▪Suction muffler:....................not required
Alternative configuration
▪Tubing configuration: ...........small shock loop
▪Service valve:......................."straight through" valve fastened to unit / wall
▪Suction muffler:....................may be required (acts as dampening mass)

C6.2.41/0219/E 13
4 Electrical connection
4.1 General recommendations
The compressor terminal box has a wiring diagram on the inside of its cover. Before connecting
the compressor, ensure the supply voltage, the phases and the frequency match the nameplate
data.
4.2 Electrical installation
Single-phase (PF*) compressors:
Power circuit Control circuit
Motor terminal connections
Single-phase compressors are connected to the
Common (C), Start (S) and Run (R) connections
Legend
B1 ....... Room thermostat K1........Contactor
B3 ....... Discharge gas thermostat R2........Crankcase heater
C2....... Run capacitor S1........Auxiliary switch
F1 ....... Fuse
F3 ....... HP switch
F4 ....... LP switch
Figure 9

14 C6.2.41/0219/E
Three-phase compressors (TF*) with internal motor protection:
Power circuit Control circuit
Motor terminal connections
Three-phase compressors are connected to the T1,
T2 and T3 connections
Legend
B1 ....... Room thermostat K1........Contactor
B3 ....... Discharge gas thermostat R2........Crankcase heater
F1 ....... Fuse S1........Auxiliary switch
F3 ....... HP switch
F4 ....... LP switch
Figure 10

C6.2.41/0219/E 15
4.2.1 Terminal box
The standard terminal box is IP21 for all ZR*KRE compressors.
Cable glands have an influence on the protection class of the terminal box. Emerson strongly
recommends to use appropriate cable glands in order to reach the rated protection class.
Installers/service providers are advised to pay attention to this aspect every time they install or
replace a Copeland Scroll compressor and to use cable glands according to EN 50262 or any
other relevant standard of application in their country/region. Examples of correct electrical
installations are shown in Figure 11 below.
Figure 11: Correct electrical installation with cable glands for IP21 T-box
4.2.2 Motor windings
Compressor models from ZR24KRE to ZR48KRE are offered with either a single-phase or a three-
phase induction motor. ZR69KRE is only available in a single phase version. Compressor models
from ZR61KRE to ZR92KRE are only available with three-phase motors. All three-phase motors
are connected in star; single-phase motors need a run capacitor.
The motor insulation material is class "B" (TF*) for all compressor models covered in these
guidelines.
4.2.3 Protection devices
Independently from the internal motor protection, fuses must be installed before the compressor.
The selection of fuses has to be carried out according to VDE 0635, DIN 57635, IEC 269-1 or
EN 60-269-1.
4.2.4 Crankcase heaters
IMPORTANT
Oil dilution! Bearing malfunction! Turn the crankcase heater on 12 hours
before starting the compressor.
A crankcase heater is used to prevent refrigerant migrating into the shell during standstill periods.
Due to the Copeland scroll’s inherent ability to handle liquid refrigerant in flooded conditions a
crankcase heater is not required when the system charge does not exceed the charge limits
indicated in Table 5.
Compressor
Refrigerant
charge limit
ZR24KRE to ZR48KRE
3.6 kg
ZR61KRE to ZR92KRE
4.5 kg
Table 5

16 C6.2.41/0219/E
If a crankcase heater is fitted it is recommended that
the heater be turned on for a minimum of 12 hours
prior to starting the compressor. This will prevent oil
dilution and bearing stress on initial start up. The
crankcase heater must remain energised during
compressor off cycles.
The crankcase heater must be mounted below the oil
schraeder valve located on the bottom shell (see
Figure 12).
Figure 12: Crankcase heater location
4.3 Pressure safety controls
4.3.1 High-pressure control
The cut-out setting for the high-pressure control shall be determined according to regional
standards, usually EN 378, part 2 in Europe.
The maximum pressure value for the individual compressor type, PS high side, is printed on the
nameplate of the compressor.
The high-pressure cut-out should have a manual reset feature for the highest level of system
protection.
4.3.2 Low-pressure control
The minimum cut-out setting shall be determined according to the refrigerant and to the allowed
operation envelope –see technical data in Select software at www.climate.emerson.com/en-gb.
For example, a minimum cut-out setting of 0.5 bar(g) is required for ZR compressors using R513A.
The low-pressure cut-out should have a manual reset feature for the highest level of system
protection.
4.3.3 Internal pressure relief valve
There is an internal pressure relief valve on all ZR24KRE to ZR92KRE scroll compressors, which
opens at a differential pressure of 28 bar ± 3 bar between high- and low-pressure sides. A high-
pressure cut-out may be required according to national regulations and is strongly recommended
due to the capabilities of pumping to high pressures once the discharge is obstructed.
The IPR valve is a safety device, not an HP switch. It is not designed for repeated operation and
there is no guarantee that it will reset correctly if it does have repeated operation.
4.4 Discharge temperature protection
The use of an external discharge thermostat is required for compressor model ZR92KRE.
A discharge thermostat can be used but is not mandatory for compressor models ZR24KRE to
ZR81KRE because these models have an internal thermodisc which is positioned next to the
discharge port of the scroll set. When the thermodisc opens, a small gas by-pass occurs which
trips the Klixon motor protector. The internal thermodisc opens at 146°C ± 4K and closes at
91°C ± 7K.
Internal discharge temperatures can reach unacceptable values under some extreme operating
conditions (such as loss of refrigerant injection charge or extremely high compression ratio). This
could cause compressor damage.
The discharge thermostat dedicated to R450A and R513A has a cut-out setting of 130°C ± 4K
with closing at 101°C ± 8K and should be installed approximately 120 mm from the discharge
valve outlet (see assembly instructions below).
To ensure proper functioning and to avoid false readings, the discharge line thermostat must be
installed and insulated according to the procedure and recommendations hereunder.

C6.2.41/0219/E 17
Assembly of the discharge line thermostat
▪Install the discharge line thermostat on the
discharge tube 120 mm from top cap.
▪Snap the retainer clip over the tube and onto
the thermostat.
▪The thermostat should be placed on the
discharge tube so that its body is in upward
position on a horizontal tube installation.
▪Ensure that the thermostat is not tilted.
▪The wire must not be in contact with the top
cap of the compressor or the discharge tube.
Care should be taken to route wires so that
they do not come into contact with sharp
objects.
▪To avoid any impact on tripping temperature
by the ambient, the discharge line thermostat
must be insulated.
▪Wrap thermal insulation around the pipe left
and right of the thermostat and secure it with
plastic straps.
▪Wrap a second layer of insulation around the
first one and around the thermostat, and
secure it with plastic straps.
4.5 High-potential testing
WARNING
Conductor cables! Electrical shock! Shut off power supply before high-
potential testing.
CAUTION
Internal arcing! Motor destruction! Do not carry out high-voltage or
insulation tests if the compressor housing is under vacuum.
Emerson subjects all Scroll compressors to a high-voltage test after final assembly. Each motor
phase winding is tested, according to EN 0530 or VDE 0530 part 1, at a differential voltage of
1000V plus twice the nominal voltage. Since high-voltage tests lead to premature ageing of the
winding insulation further additional tests of that nature are not recommended.
If it has to be done for any reason, a lower voltage must be used. Disconnect all electronic devices,
eg, motor protection module, fan speed control, etc prior to testing.