C060220_Installation - Climate Center Online

C060220_Installation - Climate Center Online
Scroll Compressors for Refrigeration
“Summit” Series
ZB50K* to ZB114K*
1
Safety instructions ............................................................................................ 1
1.1 Icon explanation.................................................................................................................1
1.2 Safety statements ..............................................................................................................1
1.3 General instructions ...........................................................................................................2
2
Product description .......................................................................................... 2
2.1 Common information about Copeland Scrollв„ў compressors............................................2
2.2 About this guideline............................................................................................................2
2.3 Nomenclature.....................................................................................................................2
2.4 Application range ...............................................................................................................3
3
2.4.1
Qualified refrigerants and oils ................................................................................3
2.4.2
Application limits.....................................................................................................3
Installation ......................................................................................................... 4
3.1 Compressor handling.........................................................................................................4
3.1.1
Transport and storage ............................................................................................4
3.1.2
Positioning and securing ........................................................................................4
3.1.3
Installation location.................................................................................................4
3.1.4
Mounting parts........................................................................................................4
3.2 Brazing procedure..............................................................................................................5
3.3 Shut-off valves and adaptors .............................................................................................6
3.4 Suction accumulators.........................................................................................................6
3.5 Screens ..............................................................................................................................7
3.6 Mufflers ..............................................................................................................................7
3.7 Suction line noise and vibration .........................................................................................7
4
Electrical connection ........................................................................................ 8
4.1 General recommendations.................................................................................................8
4.2 Electrical installation ..........................................................................................................8
4.2.1
Terminal box...........................................................................................................8
4.2.2
Motor windings .......................................................................................................8
4.2.3
Protection devices ..................................................................................................9
4.2.4
Crankcase heaters .................................................................................................9
4.3 Pressure safety controls ....................................................................................................9
4.3.1
High-pressure control .............................................................................................9
4.3.2
Low-pressure control..............................................................................................9
4.4 Discharge temperature protection .....................................................................................9
4.5 Motor protection ...............................................................................................................10
4.6 High-potential testing .......................................................................................................10
5
Starting up & operation................................................................................... 11
5.1 Strength pressure test......................................................................................................11
5.2 Tightness/pressure test....................................................................................................11
5.3 System evacuation...........................................................................................................11
C6.2.20/0309/E
5.4 Charging procedure .........................................................................................................12
5.5 Preliminary checks – Pre-starting ....................................................................................12
5.6 Rotation direction .............................................................................................................12
5.7 Starting.............................................................................................................................13
5.8 Deep vacuum operation...................................................................................................13
5.9 Shell temperature.............................................................................................................13
5.10 Pump down cycle.............................................................................................................13
5.11 Minimum run time ............................................................................................................13
5.12 Shut-off sound..................................................................................................................13
6
Maintenance & repair ...................................................................................... 14
6.1 Exchanging the refrigerant...............................................................................................14
6.2 Rotalock valves ................................................................................................................14
6.3 Replacing a compressor ..................................................................................................14
6.3.1
Compressor replacement .....................................................................................14
6.3.2
Start-up of a new or replacement compressor .....................................................14
6.4 Lubrication and oil removal ..............................................................................................15
6.5 Unbrazing system components .......................................................................................15
7
Dismantling & disposal................................................................................... 16
C6.2.20/0309/E
Safety instructions
Safety
instructions
1
Copeland Scrollв„ў 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 according to the EC Machines
directive. 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 on request.
Product
description
These instructions should be retained throughout the lifetime of the compressor.
You are strongly advised to follow these safety instructions.
Icon explanation
NOTE
CAUTION
This icon indicates instructions to
avoid property damage and possible
personal injury.
IMPORTANT
This icon indicates instructions to
avoid malfunction of the compressor.
This
word
indicates
a
recommendation for easier operation.
Installation
WARNING
This icon indicates instructions to
avoid personal injury and material
damage.
High voltage
This icon indicates operations with a
danger of electric shock.
Danger of burning or frostbite
This icon indicates operations with a
danger of burning or frostbite.
Explosion hazard
This icon indicates operations with a
danger of explosion.
Electrical
connection
1.1
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.
Starting up &
operation
1.2
Dismantling &
disposal
Maintenance &
repair
Use personal safety equipment.
Safety goggles, gloves,
protective clothing, safety boots and hard hats should be worn
where necessary.
C6.2.20/0309/E
1
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.
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.
IMPORTANT
Transit damage! Compressor malfunction! Use original packaging. Avoid
collisions and tilting.
2
Product description
2.1
Common information about Copeland Scrollв„ў compressors
The Scroll compressor has been under development at Emerson Climate Technologies since
1979. It is the most efficient and durable compressor Emerson Climate Technologies has ever
developed for air-conditioning and refrigeration.
This application guideline deals with Summit Series vertical single Copeland Scrollв„ў
compressors ZB50K* to ZB114K* for refrigeration applications.
These compressors have one Scroll compression set driven by a 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
About this guideline
This guideline is intended to enable users to ensure the safe installation, starting, operation and
maintenance of Copeland Scrollв„ў compressors.
This guideline is not intended to replace the system expertise available from system
manufacturers.
2.3
Nomenclature
The model designation contains the following technical information about the standard and
vapour injection compressors:
Z B 76K C E - TFD - 551
Bill of material number
Motor version
Oil type:
E = POE oil
Model variation
Nominal capacity [BTU/h] @ 60 Hz and * ARI conditions
Application range temperature:
B = high/medium *
Compressor family: Z = Scroll
2
C6.2.20/0309/E
Liquid sub-cooling
Ambient temperature
0K
35В°C
Safety
instructions
* ARI Conditions high/medium temperature: R404A
Evaporating temperature –6.67°C
Condensing temperature 48.90В°C
Suction gas return
18.33 K
Application range
2.4
2.4.1 Qualified refrigerants and oils
Product
description
IMPORTANT
It is essential that the glide of refrigerant blends (primarily R407C) is
carefully considered when adjusting pressure and superheat controls.
Oil recharge values can be taken from Copeland Scrollв„ў compressors brochures or CopelandВ®
Brand Products Selection Software.
ZB
Compressor
50K, 58K, 66K, 76K, 95K, 114K
Qualified
Refrigerants
CopelandВ®
Brand Products
Standard Oil
Servicing Oil
Installation
R404A, R134a, R22
Emkarate RL 32 3MAF
Emkarate RL 32 3MAF, Mobil EAL Arctic 22 CC
Table 1
Electrical
connection
2.4.2 Application limits
The application envelopes shown below are for R404A only. For other refrigerant application
envelopes please refer to CopelandВ® Brand Products Selection Software found at
www.emersonclimate.eu.
60
o
Condensing Temperature tc ( C)
60
Starting up &
operation
ZB95KCE to ZB114KCE
70
50
40
R404A
30
20
10
0
50
40
R404A
30
Maintenance &
repair
o
20
10
0
-35
-30
-25
-20
-15
-10
-5
0
5
o
10
Evaporating Temperature to ( C)
15
-35
-30
-25
-20
-15
-10
-5
0
5
10
15
o
Evaporating Temperature to ( C)
Dismantling &
disposal
Condensing Temperature tc ( C)
ZB50KCE to ZB76KCE
70
10K Suction Superheat
o
25 C Suction Gas Return
Figure 1: Application envelopes with R404A
C6.2.20/0309/E
3
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. Stack pallets on top of each other when not exceeding
300 kg. Do not stack single boxes on top of each other. Keep the packaging
dry at all times.
Figure 2
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.
For models ZB50KCE to ZB114KCE the suction connection plug must be left in place until the
compressor is set into the unit otherwise oil might spill out of the suction connection located low
on the shell. 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. No object, eg, a swaging tool should be inserted deeper than
51 mm into the suction tube or it might damage the suction screen and motor.
3.1.3 Installation location
Ensure the compressors are installed on a solid level base.
3.1.4 Mounting parts
Four vibration absorber grommets are supplied 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 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 В± 1 Nm. It is critically important that the grommet is not
compressed. A clearance space of approximately 2 mm between the bottom of the washer and
the top of the grommet spacer is recommended.
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, or on request to deliver the compressor with these parts
instead of the rubber grommets.
4
C6.2.20/0309/E
Safety
instructions
Mounting clearance
2 mm
Product
description
Mounting parts: ZB50KC* to ZB114KC* - Soft mountings
Figure 3
3.2
Brazing procedure
Electrical
connection
Installation
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.
Figure 4: Suction tube brazing
Starting up &
operation
Copeland Scrollв„ў 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.
Since the discharge stub contains a check valve, care
must be taken not to overheat it to prevent brazing
material to flow into it.
Figure 4 shows the proper procedures for brazing the suction and discharge lines to a Scroll
compressor.


Maintenance &
repair




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.
Dismantling &
disposal

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.
C6.2.20/0309/E
5
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 5
Copeland Scrollв„ў compressors are delivered with a discharge check valve fitted inside the
discharge port and rubber plugs fitted to the suction and discharge ports as standard. There are
options to fit either Rotalock valves, or Rotalock adaptors. Using either straight or angled
adaptors provides a way to convert a Rotalock into a brazing connection.
Refer to Table 2 for proper tightening torques:
Rotalock 3/4"16UNF
Rotalock 1”-14UNS
Rotalock 1"1/4-12UNF
Rotalock 1"3/4-12UNF
Rotalock 2"1/4-12UNF
NOTE: More information concerning
adaptors and shut-off valves can be found
in the "Spare parts list".
C_T_SCA_002
Table 2
3.4
Torque [Nm]
40-50
70-80
110-135
135-160
165-190
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
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 an accumulator is dependent on the application. If an
accumulator must be used, the oil-return orifice should be 2.0 mm in diameter for all models.
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.
6
C6.2.20/0309/E
3.5
Screens
Safety
instructions
CAUTION
Screen blocking! Compressor breakdown! Use screens with at least
0.6 mm openings.
3.6
Product
description
The use of screens finer than 30 x 30 mm/inch mesh anywhere in the system should be avoided
with these compressors. Field experience has shown that fine 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.
Mufflers
3.7
Installation
External mufflers, normally applied to piston compressors in the past, may not be required for
Copeland Scrollв„ў 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 10 – 15 cm length x
4 cm depth.
Suction line noise and vibration
Maintenance &
repair
Starting up &
operation
Electrical
connection
Copeland Scrollв„ў 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
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 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
Figure 6: Suction tube design
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.
Dismantling &
disposal
A second difference of the Copeland Scrollв„ў 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.
Recommended configuration
- Tubing configuration:
small shock loop
- Service valve:
"angled valve" fastened to unit / wall
- Suction muffler:
not required
Alternative configuration
- Tubing configuration:
- Service valve:
- Suction muffler:
C6.2.20/0309/E
small shock loop
"straight through" valve fastened to unit / wall
may be required (acts as dampening mass)
7
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
Three-phase compressors (TF*) with internal motor protection:
Power circuit
Control circuit
Motor terminal connections
Tri-phase compressors are connected to theT1, T2
and T3 connections
Legend
B1 Room thermostat
B3 Discharge gas thermostat
F1 Fuse
F3 HP switch
F4 LP switch
K1
R2
S1
Y5
Contactor
Crankcase heater
Auxiliary switch
Solenoid valve for refrigeration injection
Figure 7
4.2.1 Terminal box
The terminal box is IP21 for all models (IEC 34).
4.2.2 Motor windings
These Scroll compressors are offered with a three-phase induction motor. All three-phase
motors are connected in star.
The motor insulation material is class "B" (TF*) for compressor models covered in this guideline.
This is according to VDE 0530, IEC 34-1 or DIN 57530.
8
C6.2.20/0309/E
4.2.3 Protection devices
Safety
instructions
Independently from the internal motor protection, fuses must be installed before the compressor.
Selection of fuses has to be carried out according to VDE 0635, DIN 57635, IEC 269-1or EN 60269-1.
4.2.4 Crankcase heaters
Product
description
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 crankcase heater is not required when the system charge does not exceed 7.5kg.
Installation
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 8.
Figure 8: Crankcase heater location
4.3
Pressure safety controls
Electrical
connection
4.3.1 High-pressure control
A high-pressure control with a maximum cut out setting of 28 bar(g) must be used with this range
of compressors.
The high-pressure control should have a manual reset feature for the highest level of system
protection.
4.3.2 Low-pressure control
Starting up &
operation
The low-pressure cut-out should be set as high as possible. The normal minimum is 2.6 bar(g).
The low-pressure control should have a manual reset feature for the highest level of system
protection.
4.4
Discharge temperature protection
Dismantling &
disposal
Maintenance &
repair
ZB50KCE to ZB114KCE Scroll compressors have the addition of the Advanced Scroll
Temperature Protection (ASTP). The Advanced Scroll Temperature Protection is also a
temperature sensitive thermo-disc that acts to protect the compressor from discharge gas
overheating. Once the discharge gas reaches a critical temperature, the ASTP feature will cause
the scrolls to separate and stop pumping although the motor continues to run. After running for
some time without pumping gas, the motor protector will open.
Figure 9: Advanced Scroll Temperature Protection (ASTP)
C6.2.20/0309/E
9
NOTE: Depending upon the heat build-up in the compressor, it may take up to two hours
for the ASTP and motor protector to reset!
To identify compressors with Advanced Scroll Temperature Protection, a label has been added
above the terminal box.
4.5
Motor protection
For the ZB50KCE to ZB114KCE range of compressors, conventional inherent internal line break
motor protection is provided.
4.6
High-potential testing
WARNING
Conductor cables! Electrical shock! Shut off power supply before highpotential testing.
CAUTION
Internal arcing! Motor destruction! Do not carry out high-voltage or
insulation tests if the compressor housing is under vacuum.
Emerson Climate Technologies 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.
10
C6.2.20/0309/E
Starting up & operation
Safety
instructions
5
WARNING
Diesel effect! Compressor destruction! The mixture of air and oil at high
temperature can lead to an explosion. Avoid operating with air.
5.1
Product
description
IMPORTANT
Oil dilution! Bearing malfunction! Turn the crankcase heater on 12 hours
before starting the compressor.
Strength pressure test
The compressor has been strength-tested in the factory. It is not necessary for the customer to
strength- or leak-test the compressor again although the compressor will normally be exposed to
the testing made as part of system testing.
5.2
Tightness/pressure test
Installation
WARNING
High pressure! Personal injuries! Consider personal safety requirements
and refer to test pressures prior to test.
WARNING
System explosion! Personal injuries! DO NOT USE other industrial
gases.
Electrical
connection
CAUTION
System contamination! Bearing malfunction! Use only dry nitrogen or
dried air for pressure testing.
If using dry air do not include the compressor in the pressure test – isolate it first. Never add
refrigerant to the test gas (as leak indicator).
System evacuation
Starting up &
operation
5.3
Maintenance &
repair
Before the installation is put into commission, it has to be evacuated with a vacuum pump.
Proper evacuation reduces residual moisture to 50 ppm. During the initial procedure, suction and
discharge shutoff valves on the compressor remain closed. The installation of adequately sized
access valves at the furthest point from the compressor in the suction and liquid lines is
advisable. Pressure must be measured using a vacuum pressure (Torr) gauge on the access
valves and not on the vacuum pump; this serves to avoid incorrect measurements resulting from
the pressure gradient along the connecting lines to the pump.
Evacuating the system only on the suction side of a Scroll compressor can occasionally result in
a temporary no start condition for the compressor. The reason for this is that the floating seal
could axially seal with the scroll set, with the higher pressure on the floating seal. Consequently,
until the pressures equalise, the floating seal and scroll set can be held tightly together. The
installation should be evacuated down to 0.3 mbar / 0.22 Torr.
C6.2.20/0309/E
Dismantling &
disposal
Subsequently, the factory holding charge of dry air in the compressor is released to the ambient.
The shut-off valves are opened and the installation, including the compressor, is once more
evacuated as described after the system has been recharged with dry nitrogen. Highest
demands are placed on the leak proof design of the installation and on leak testing methods
(please refer to EN378).
11
5.4
Charging procedure
Do not operate compressor without enough system charge to maintain at least 0.3 bar
suction pressure.
Do not operate with a restricted suction.
Do not operate with the low-pressure cut-out bridged.
Allowing pressure to drop below 0.3 bar 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 high-pressure cut-out.
Bearings are susceptible to damage before they have had several hours of normal
running in.
The system should be liquid-charged through the liquid-receiver shut-off valve or through a valve
in the liquid line. The use of a filter drier in the charging line is highly recommended. Because
scrolls have discharge check valves, systems should be liquid-charged on both the high and low
sides simultaneously to ensure a positive refrigerant pressure is present in the compressor
before it runs. The majority of the charge should be placed in the high side of the system to
prevent bearing washout during first-time start on the assembly line.
5.5
Preliminary checks – Pre-starting
CAUTION
Vacuum operation! Compressor damage!
Discuss details of the installation with the installer. If possible, obtain drawings, wiring diagrams,
etc.
It is ideal to use a check-list but always check the following:









5.6
Visual check of the electrics, wiring, fuses etc.
Visual check of the plant for leaks, loose fittings such as TXV bulbs etc.
Compressor oil level
Calibration of HP & LP switches and any pressure actuated valves
Check setting and operation of all safety features and protection devices
All valves in the correct running position
Pressure and compound gauges fitted
Correctly charged with refrigerant
Compressor electrical isolator location & position
Rotation direction
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. Three-phase compressors will rotate in either
direction depending upon phasing of the power to L1, L2 and L3. 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.
Observing that suction pressure drops and discharge pressure rises when the compressor is
energized allows verification of proper rotation direction. There is no negative impact on
durability caused by operating three-phase Copeland Scrollв„ў compressors in the reversed
direction for a short period of time (under one hour) but oil may be lost. Oil loss can be prevented
during reverse rotation if the tubing is routed at least 15 cm above the compressor. After several
minutes of operation in reverse, the compressor's protection system will trip due to high motor
temperature. The operator will notice a lack of cooling. However, if allowed to repeatedly restart
and run in reverse without correcting the situation, the compressor will be permanently
damaged.
All three-phase Scroll compressors are identically wired internally. Therefore, once the correct
phasing is determined for a specific system or installation, connecting properly phased power
leads to the identified compressor terminals will ensure proper rotation direction.
It is important to include notices and instructions in appropriate locations on the equipment to
ensure proper rotation direction when the system is installed and operated.
12
C6.2.20/0309/E
5.7
Starting
Deep vacuum operation
Product
description
5.8
Safety
instructions
During the very brief start-up, a clicking sound is audible, resulting from initial contacting of the
spirals and is normal. No start assist devices are required for single-phase compressors, even if
a system uses non-bleed expansion valves. Due to the 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 start-up, lowvoltage starting characteristics are excellent for Copeland Scrollв„ў compressors. Moreover, if low
voltage conditions exist at start up, protector trips could result.
5.9
Installation
Copeland Scrollв„ў compressors should never be used to evacuate a refrigeration or airconditioning system. The Scroll compressor can be used to pump down refrigerant in a unit as
long as the pressures remain within the operating envelope. Low suction pressures will result in
overheating of the scrolls and permanent damage to the compressor drive bearing or cause the
ASTP to activate. Scroll compressors incorporate internal low vacuum protection; the floating
seal unloads when the pressure ratio exceeds approximately 10:1 for ZB.
Shell temperature
Electrical
connection
The top shell and discharge line can briefly but repeatedly reach temperatures above 177В°C if
the compressor cycles on its internal protection devices. This only happens under rare
circumstances and can be caused by the failure of system components such as the condenser
or evaporator fan or loss of charge and depends upon the type of expansion control. Care must
be taken to ensure that wiring or other materials that could be damaged by these temperatures
do not come in contact with the shell.
5.10 Pump down cycle
To control refrigerant migration a pump down system should be used. The discharge check
valve with a refrigeration scroll compressor is designed for low leak back and will allow the use
of a pumpdown without the addition of an external check valve.
Starting up &
operation
If the compressor is stationary for prolonged periods, refrigerant could migrate into the
compressor and therefore a crankcase heater must be installed.
If cold air is constantly drawn over the compressor this could make the crankcase heater
ineffective and therefore a pump down system is recommended.
Maintenance &
repair
For ZB models care should be taken because the scroll sets will unload at a pressure ratio of
approximately 10:1. If the unit fails to pump down the pumpdown pressure should be reset to a
higher value. The low-pressure control differential for all models needs to be reviewed since a
relatively lower volume of gas will reexpand from the discharge plenum of the compressor into
the low side on shutdown.
5.11 Minimum run time
Dismantling &
disposal
Emerson Climate Technologies recommends a maximum of 10 starts per hour. 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 start-up. 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 start-up to return to the compressor
sump and restore a minimal oil level that will ensure 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.
5.12 Shut-off sound
The Scroll compressors incorporate a device which limits reverse rotation. The momentary
reversal of direction of the scrolls has no effect on compressor durability and is entirely normal.
C6.2.20/0309/E
13
6
Maintenance & repair
6.1
Exchanging the refrigerant
Qualified refrigerants and oils are given in section 2.4.1.
It is not necessary to replace the refrigerant with new unless contamination due to an error such
as topping up the system with an incorrect refrigerant is suspected. To verify correct refrigerant
composition, a sample can be taken for chemical analysis. A check can be made during shut
down by comparing the refrigerant temperature and pressure using precision measurements at a
location in the system where liquid and vapour phases are present and when the temperatures
have stabilised.
In the event that the refrigerant needs replacing, the charge should be recovered using a
suitable recovery unit.
6.2
Rotalock valves
Rotalock valves should be periodically re-torqued to ensure that leak prevention tightness is
maintained.
6.3
Replacing a compressor
CAUTION
Inadequate lubrication! Bearing destruction! Exchange the accumulator
after replacing a compressor with a burned out motor. The accumulator oil
return orifice or screen may be plugged with debris or may become plugged.
This will result in starvation of oil to the new compressor and a second
failure.
6.3.1 Compressor replacement
In the case of a motor burnout, the majority of contaminated oil will be removed with the
compressor. The rest of the oil is cleaned through the use of suction and liquid line filter driers. A
100% activated alumna suction line filter drier is recommended but must be removed after 72
hours. It is highly recommended that the suction accumulator be replaced if the system
contains one. This is because the accumulator oil return orifice 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. When a single compressor or tandem is
exchanged in the field, it is possible that a major portion of the oil may still be in the system.
While this may not affect the reliability of the replacement compressor, the extra oil will add to
rotor drag and increase power usage.
6.3.2 Start-up of a new or replacement compressor
Rapid charging only on the suction side of a scroll-equipped system or condensing unit can
occasionally result in a temporary no start condition for the compressor. The reason for this is
that, if the flanks of the compressor happen to be in a sealed position, rapid pressurisation of the
low side without opposing high-side pressure can cause the scrolls to seal axially. As a result,
until the pressures eventually equalise, the scrolls can be held tightly together preventing
rotation. The best way to avoid this situation is to charge on both the high and low sides
simultaneously at a rate which does not result in axial loading of the scrolls.
A minimum suction pressure of 1.75 bar must be maintained during charging. Allowing pressure
to drop below 0.3 bar for more than a few seconds may overheat scrolls and cause early drive
bearing damage. 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 securely electrically locking
out the system. This will prevent unauthorised personnel from accidentally operating the system
and potentially ruining the compressor by operating with no refrigerant flow. 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 causing burnout of the internal lead connections.
14
C6.2.20/0309/E
6.4
Lubrication and oil removal
Safety
nstructions
WARNING
Chemical reaction! Compressor destruction! Do not mix up ester oils with
mineral oil and/or alkyl benzene when used with chlorine-free (HFC)
refrigerants.
Product
description
The compressor is supplied with an initial oil charge. The standard oil charge for use with
refrigerants R404A / R134a / R22 is a polyolester (POE) lubricant Emkarate RL 32 3MAF. In the
field the oil level could be topped up with Mobil EAL Arctic 22 CC if 3MAF is not available. See
nameplate for original oil charge shown in litres. A field recharge is from 0.05 to 0.1 litre less.
Electrical
connection
Installation
One disadvantage of POE is that it is far more hygroscopic than mineral oil (see Figure 10).
Only brief exposure to ambient air is needed for POE to absorb sufficient moisture to make it
unacceptable for use in a refrigeration system. Since POE holds moisture more readily than
mineral oil it is more difficult to remove it through the use of vacuum. Compressors supplied by
Emerson Climate Technologies contain oil with low moisture content, and it may rise during the
system assembling process. Therefore it is recommended that a properly sized filter-drier is
installed in all POE systems. This will maintain the moisture level in the oil to less than 50 ppm. If
oil is charged into a system, it is recommended to use POE with a moisture content no higher
than 50 ppm.
Starting up &
operation
Figure 10: Absorption of moisture in ester oil in comparison to mineral oil in ppm by weight at 25В°C and 50%
relative humidity (h=hours)
6.5
Maintenance &
repair
If the moisture content of the oil in a refrigeration system reaches unacceptably high levels,
corrosion and copper plating may occur. The system should be evacuated down to 0.3 mbar or
lower. If there is uncertainty as to the moisture content in the system, an oil sample should be
taken and tested for moisture. Sight glass/moisture indicators currently available can be used
with the HFC refrigerants and lubricants; however, the moisture indicator will just show the
moisture content of the refrigerant. The actual moisture level of POE would be higher than the
sight glass indicates. This is due to the high hygroscopicity of the POE oil. To determine the
actual moisture content of the lubricant, samples have to be taken from the system and
analysed.
Unbrazing system components
Dismantling &
disposal
WARNING
Explosive flame! Burning! Oil-refrigerant mixtures are highly flammable.
Remove all refrigerant before opening the system. Avoid working with an
unshielded flame in a refrigerant charged system.
Before opening up a system it is important to remove all refrigerant from both the high and low
sides of the system. If the refrigerant charge is removed from a scroll-equipped unit from the
high side only, it is possible for the scrolls to seal, preventing pressure equalization through the
compressor. This may leave the low side shell and suction line tubing pressurized. If a brazing
torch is then applied to the low side while the low side shell and suction line contain pressure,
the pressurized refrigerant and oil mixture could ignite when it escapes and contacts the brazing
flame. To prevent this occurrence, it is important to check both the high and low sides 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.
C6.2.20/0309/E
15
7
Dismantling & disposal
Removing oil and refrigerant:
Do not disperse in the environment.
Use the correct equipment and method of removal.
Dispose of oil and refrigerant properly.
Dispose of compressor properly.
16
C6.2.20/0309/E
C6.2.20/0309/E
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For more details, see www.emersonclimate.eu
Emerson Climate Technologies - European Headquarters
- Pascalstrasse 65 - 52076 Aachen, Germany
Phone: +49 (0) 2408 929 0 - Fax: +49 (0) 2408 929 570 - Internet: www.emersonclimate.eu
The Emerson Climate Technologies logo is a trademark and service mark of Emerson Electric Co. Emerson Climate Technologies Inc. is a subsidiary of Emerson Electric Co.
Copeland is a registered trademark and Copeland Scroll is a tr ademark of Emerson Climate Technologies Inc.. All other trademark s are property of their respective owners.
Information contained in this brochure is subject to change without notifi cation.
В© 2011 Emerson Climate Technologies, Inc.
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+40 - 364 - 73 11 72
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