OSTROV OA331 User manual

06.2018
Operating Instructions
CONDENSING UNITS
OA331

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Table of contents
Introduction 3
1 Terms and definitions 3
2 General information 3
3 Areas of responsibility 5
3.1 Manufacturer’s responsibilities 5
3.2 System installer’s responsibilities 5
3.3 Owner or operator responsibilities 6
4 General information on safety requirements 6
4.1 Safety of the refrigeration system 7
4.2 Safety signs 7
4.3 Personnel requirements 7
4.4 Hazards, hazardous situations and hazardous events 7
4.5 Personal protective equipment 7
5 Packaging 10
6 Storage 10
7 Transportation 11
8 Placement 12
9 Mounting 12
9.1 Unpacking 12
9.2 Check the factory pressure 13
9.3 Installation 14
9.4 Connection of pipelines of refrigerant circuit 15
9.5 Connection of pipelines of chilled water loop 15
9.6 Electrical connection 17
10 Commissioning 17
10.1 Connection to the circuit of the refrigeration system 18
10.2 Tightness test pressure 18
10.3 Vaccum procedure 18
10.4 Charge by a refrigerant 18
10.5 Changing the chilled water loop 19
10.6 Start up 19
10.7 Check after the unit is operational 20

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11 Operation 21
12 Shutdown 21
13 Maintenance 21
14 Decommissioning for a prolonged period 22
15 Decommissioning and disposal 23
16 Declaration of conformity 23
Appendix 1. Requirements for heat transfer fluids for chilled water loop 24

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Introduction
These operating instructions contain important information
on installation, use and maintenance of OSTROV OA331
condensing units (hereinafter referred to as the units).
Please read the instructions carefully before operating the
equipment and keep them in the unit’s immediate vicinity
during its entire lifetime.
Observance of these instructions helps in avoiding dangers,
reducing repair costs and down-times and increasing the
reliability and durability of the unit.
Ignoring the information given in these instructions can put
the warranty rights at risk.
The instructions cannot cover every installation, use or
service situation. If you need more detailed information,
contact us directly.
In addition to these instructions, refer to the manufacturer
documentation for the individual components of the unit.
Osrtov reserves the right to modify its products as it deems
necessary without altering their main characteristics.
Specifications are subject to change without notice.
All names referred to are registered trademarks of their
respective owners.
Ostrov assumes no responsibility for any errors and
misprints that these operating instructions may contain.

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1 Terms and definitions
The following definitions are used in these operating
instructions:
«Manufacturer» means the legal person who has designed
and manufactured the unit.
«System installer» means a legal person who installs and
commissions the unit.
«Owner» means a legal person who owns, uses and
disposes of the unit.
«Operator» means a legal person who operates and
maintains the unit.
«Condensing unit» means a combination of one or more
compressors, condensers, liquid receivers (when required)
and the regularly furnished accessories.
«Refrigerating system» means a combination of
interconnected refrigerant-containing parts constituting one
closed refrigerant circuit in which the refrigerant is circulated
for the purpose of extracting and rejecting heat.
«Refrigerant» means a fluid used for heat transfer in
a refrigerating system, which absorbs heat at a low
temperature and a low pressure and rejects heat at a higher
temperature and a higher pressure usually involving changes
of the state of the fluid.
«Сhilled water loop» means a closed loop inside which the
heat transfer fluid circulates, to cool the condenser.
«Heat transfer fluid» means a liquid used in the heat
transfer process.
2 General Information
OSTROV OA331 condensing units (hereinafter referred to
as the units) are completely factory-assembled and built in
compliance with current international and national standards
in the specific field of refrigeration systems.
These units have a protective housing made of galvanized
powder-coated steel and are intended for indoor installation.
They are equipped with a hermetic piston compressor.
The unit is equipped with a high-eciency plate water
cooled condenser.
The units are used as part of refrigeration systems for
technological processes and conditioning in industrial plants,
equipping storage and freezing rooms, manufacturing food
products and in trade organizations.
The refrigerant circuit of each unit is tested for strength
and leaks. Before delivery, the circuit is charged with dry
nitrogen up to excess pressure.
The units must be operated only within the limits specified
on the identification plate as well as in these operating
instructions. If they are used under other operating
conditions, the manufacturer does not guarantee their
eciency.
The identification plate of the unit contains the following
information:
• trademark, name, location and phone number of the
manufacturer;
• model of condensing unit;
• code;
• serial number;
• power supply (voltage / frequency / maximum current);
• net weight;
• refrigerant;
• maximum allowable pressure;
• test pressure (strength);
• maximum and minimum ambient temperature;
• country of origin;
• date of production (month and year).

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The scope of delivery includes the following documents:
operating instructions;
piping and instrumentation diagram;
wiring diagram;
EU Declaration of Conformity – ostrov.com.
Fig. 2.1
23 4
910 6511 78
1
Tw
out
Tw
in
1 – shut-o valve Rotalock with service valves on the unit’s housing;
2 – low pressure relays with fixed settings (mini pressure switch);
3 – compressor;
4 – high pressure relays with fixed settings (mini pressure switch);
5 – pump with frequency inverter;
6 – check valve;
7 – water cooled condenser;
8 – refrigerant receiver;
9 – filter drier;
10 – solenoid valve;
11 – shut-o valve Rotalock with service valves on the unit’s housing.
3 Areas of responsibility
3.1 Manufacturer’s responsibilities
The responsibility of the manufacturer extends to the
delivered condensing unit only.
The unit should be installed, operated and serviced by
skilled and qualified technicians only.
The manufacturer does not take any liability for the damages
and injuries occurred as a result of:
incorrect installation;
improper use;
improper operating conditions;
inadequate maintenance;
using accessories or spare parts not recommended
by the manufacturer;
using refrigerants, liquids and oils not recommended
by the manufacturer;
modifications not allowed by the manufacturer;
non-observance of these operating instructions.
All responsibilities concerning the refrigeration system, into
which the unit is integrated, are the sole responsibility of the
people involved in the appropriate working processes.
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Piping and instrumentation diagram
Refrigerant
cirquit
Chilled
water loop

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3.2 System installer’s responsibilities
The system installer’s responsibility includes designing,
manufacturing and testing the refrigeration system according
to EN 378-2, EN 378-3 and the regulations in force in the
country where the unit is installed.
The system installer is responsible for:
planning of operations required to install and
commission the system;
preparing the installation site;
installation of the refrigeration system and the
hydraulic chilled water loop in accordance with the
design documentation;
installation of automatic controls;
installation of an emergency stop switch;
testing pipelines for leaks;
providing thermal insulation;
evacuation of the system;
charging the refrigerant circuit;
charging the chilled water loop;
commissioning of the system;
start-up of the system;
specifying intervals of checking and other maintenance
operations;
informing the owner or operator about the working
principles and operating rules of the system;
other work relating to the installation and
commissioning of the refrigeration system.
The system must be provided with all equipment necessary
for testing, maintaining and repairing the system according
to EN 378-4 and the regulations in force in the country where
the unit is installed.
The system installer shall draw the attention of the owner
or operator to the necessity for adequate instruction of the
operating and supervising personnel when operating and
maintaining the system.
The system must be charged only with the refrigerant which
corresponds to the model of the condensing unit and is
indicated in the project documentation.
The system installer is responsible for informing the
manufacturer immediately if any defects of the unit are
detected.
It is recommended that the operating personnel of the owner
or operator are present during evacuation, charging with
refrigerant, heat transfer fluid, adjustment of the refrigeration
system and, if possible, during assembly on site.
3.3 Owner or operator responsibilities
The responsibility of the owner or operator includes operation,
maintenance, servicing and recovery of the refrigeration system
according to EN 378-4 and the regulations in force in the
country where the unit is installed.
The owner or operator is responsible for:
checking that the proper people are suciently trained
and qualified for operating, monitoring and servicing the
refrigeration system as well as being familiar with these
operating instructions;
informing personnel about the design of the
refrigeration system and its working principles;
informing personnel about operating and maintenance
rules of the system;
instructing personnel about handling the working
refrigerant, and heat transfer fluid, as well as about
necessary safety measures;
acceptance of the system;
providing a warning system;
planning emergency measures;
making sure that maintenance is carried out regularly;
other work according to the legislation in force in the
country where the system is used.
The owner or operator must ensure that the refrigerant used
in the system does not dier from the refrigerant which
corresponds to the model of the condensing unit and is
indicated in the project documentation.

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4 General information on safety requirements
4.1 Safety of the refrigeration system
The cooling systems into which the unit is installed must
comply with the requirements of the European machinery
directive 2006/42/EC and the European pressure equipment
directive 2014/68/EC.
prohibitory signs;
Read the instructions carefully before
operating the equipment and keep them in
the unit’s immediate vicinity during its entire
lifetime.
warning signs;
All work on the units must be carried out only
by skilled and qualified personnel who have
the required training and specialist knowledge
for their work according to EN 378 and the
regulations in force in the country where the
unit is installed.
The electrical connections must be carried
out by skilled personnel in possession of the
technical qualifications required in the country
where the unit is installed.
Non-observance of the safety rules indicated
in these operating instructions may lead to the
destruction of the unit or the entire refrigeration
system.
mandatory action signs.
4.2 Safety Signs
The following safety signs are used in these operating
instructions:
4.3 Personnel requirements
4.4 Hazards, hazardous situations and hazardous
events
Mechanical hazards
Electrical hazards
Protruding parts and corners of the units as
well as sharp edges of the fins can cause
injuries to fingers and hands.
After having finished the work, do not leave
any foreign objects inside the unit as they
may cause damage to the fans and/or the
unit after reactivation.
The fans are only intended for the transfer of
air or air-like mixtures. They must not be used
for any other purposes. There is a danger of
cutting o fingers on the rotating fan blades,
injury hazard for the hands and pulling in
danger for loose elements such as hair,
necklaces or clothing parts. Fan operation
must be carried out only with guard grilles.
Wearing jewellery is prohibited. Removal of
the guard grilles and working on the fans are
permissible only when the power supply is
switched o.
The unit can be started automatically.
Beware of unexpected activation of the fans.
Be careful when working with the refrigeration
circuit, since excessive pressure can damage
the skin and eyes.
Do not exceed the maximum allowable
pressure in the refrigerant receiver. this
can lead to its rupture. Severe injuries are
possible. When working with a pressure
vessel, wear safety glasses.
On pressurized equipment, it is prohibited to
carry out welding and soldering operations,
or to tighten threaded connections.
Prior to commencing work on the unit, ensure
that the power supply is disconnected.
Attach the label «DO NOT SWITCH ON!»
Non-observance of the safety rules indicated
in these operating instructions may lead
to the destruction of the unit or the entire
refrigeration system as well as cause severe
injuries or even death.
Make sure that the power supply is stable
and corresponds with the characteristics of
the delivered equipment.
Switching on/o the unit is allowed only
if necessary safety measures are taken to
avoid the risk of electric shock.
Direct and indirect contact with voltage-
carrying parts of motors and electrical lines
can cause serious injuries or even death.
Personnel must be trained to provide first aid
in case of electric shock.
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Fire or explosion hazards
Thermal hazards
Hazards from operating materials
The unit must be connected to the grounding
conductor.
Smoking is strictly prohibited during work. Always prevent refrigerant and oil from leaking.
When in contact with open flame or hot
surfaces (surface temperature higher than
250 °C), the refrigerants mentioned above
decompose releasing poisonous substances.
In case of any deviations from normal
operating conditions while adding refrigerant
(unusual noises, high condensing pressure
etc.), stop adding immediately and eliminate
the source of the problem.
Be careful during work with oil. In case of
contact with the skin, thoroughly wash o the
oil with soap and water. In case of contact
with the eyes, carefully rinse the eyes with
plenty of water.
In case of swallowing, do not induce vomiting
nor oer any beverages. If you feel sick after
having come in contact with oil, see a doctor
immediately.
The units are designed for compression HFC,
HFC/HFO refrigerants. These substances
belong to Group A1 refrigerants in compliance
with classification according to toxicity (A) and
flammability (1) in line with EN 378-1:
• Refrigerants which, when gaseous, are
non-flammable in air regardless of their
concentration;
• Refrigerants with a time-weighted, average
concentration that have no adverse eects
on the majority of sta who are exposed to
this concentration every day during a normal
Even after the unit is turned o, voltage
remains at inputs of the control cable and the
power supply cable as well as on the terminal
blocks to which the cables are connected.
There must be no ignition sources on the
installation site or near it.
Ensure that suitable fire extinguishing
equipment is available and ready for use
in sucient numbers. Use extinguishing
substances which are suitable for use on live
equipment.
During normal operation and during fault
conditions some components of the unit will
reach extremely high and/or low temperatures.
Accidental contacts with the headers or piping
parts can cause burns and/or frostbite.
The personnel must be trained to provide first
aid in case of burns/frostbite.
Spreading refrigerant and oil residues can lead
to ignition or explosion.
Danger of thermal burns! Avoid contact of
refrigerant with skin and clothing. Remove
contaminated and refrigerant soaked clothing
immediately. If liquid refrigerant enters the eyes
or skin, consult a doctor immediately.
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8-hour working day and a 40-hour working week.
This average concentration is greater than or
equal to 400 ml/m³.
The personnel are not exposed to any direct
danger. Group A1 refrigerants are however
generally heavier than air and can flow into
lower-lying areas. An increased concentration
can arise in static air at ground level. At high
concentrations, there is a danger of cardiac
arrhythmias and suocation due to low oxygen
levels, especially at ground level.
As a heat transfer fluid an aqueous solution of
glycol (water mix) is used. Other heat transfer
fluids are accepted only with the manufacturer’s
agreement. Glycol may cause harm to the
health. Avoid contact with skin, floor, clothing.
With ingestion agitation, glycol causes chronic
poisoning with the failure of vital organs (blood
vessels, kidneys, central nervous system).
Glycol can penetrate through the skin. In case
of contact with skin, remove clothing and wash
skin with warm soapy water. Production sta
must be equipped with special protective
clothing in accordance with industry regulations
and protections. Glycol is combustible at high
temperature in a gaseous state. The premises
must be equipped with a ventilation system
and provided with fire extinguishing equipment.
Glycol spilled on the ground or equipment,
must be washed with abundant water spray.
Liquid spilled on the floor may lead to slipping.

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4.5 Personal protective equipment
Personal protective
Stage equipment
Transportation, par. 7 ++ ++
Unpacking, par. 9.1 +++++
Installation, par. 9.3 +++++
Connection of pipelines of refrigerant circuit, par. 9.4 ++++
Commissioning, par. 10 +++++
Operation, par. 11 +++++
Maintenance, par. 13 +++++
Decommissioning, par. 14 +++ +
Decommissioning and disposal par.15 +++++
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In accordance with EN 378-3, personal protective equipment
is required to protect personnel. Individual protective
equipment must be ready for use and stored in a place
accessible to the personnel. Responsibility for the definition
and selection of personal protective equipment rests with
the Assembly Organization, the Owner and the Operating
Organization.
Summary of the personal protective equipment to be
used throughout the life of the unit is shown in the
Table 4.5
Table 4.5

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Fig. 5.1
Fig. 5.2
Fig. 5.3
5 Packaging
The units are covered with polyethylene film against
atmospheric eects. Upon the client’s request, the units
may be supplied mounted on a wooden pallet inside a
wooden crate in order to avoid transport damage (Fig. 5.1).
Units can be supplied individually wrapped (Figure 5.2), and
a total package, in a quantity that can fit on a fully loaded
pallet (Fig. 5.3).
6 Storage
The units have to be warehoused in the original packaging
until installation. It is obligatory to store them indoors. The
units must not be kept in extreme hot or cold places.
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7 Transportation
Read and follow all transport signs on the packaging of the
unit (Fig. 7.1).
The unit has to be transported and unloaded with suitable
equipment. Operators must be properly qualified for
performing loading and unloading operations.
The carrying capacity of lifting and transport equipment
must be rated for the unit’s gross weight and geometric
characteristics. The unit must be lifted from underneath with
the load spread (Fig. 7.2).
If you have any doubts about the proper transportation
method, please contact Ostrov.
In case of lifting the unit by crane, use only slings
corresponding to the type and weight of the transported
load. Take into consideration the number of sling legs and
their inclination angle. The angle between the legs must not
exceed 90° (Fig. 7.3).
Check that the forks of the forklift protrude for a sucient
length beyond the entire width of the crate (Fig.7.4).
Ensure that the unit is balanced when lifting as the weight
may not be centred.
During transportation, never stand under the load or close
to it.
Fig. 7.2
Fig. 7.1
Fig. 7.4
Fig. 7.3

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8 Placement
The units are designed for indoor placement.
The units can be installed in machinery rooms, in technical
rooms, in general-purpose rooms, as well as directly on the
housing of consumer of cold.
It is recommended to place the units in accordance with the
requirements of the standard EN 378-3, as well as national
standards and regulatory documents of the state in whose
territory the equipment is installed.
The unit should not be installed in corrosive environments.
It is forbidden to position the unit in a flammable or explosive
atmosphere as well as in environments where the risk of
electric shock is increased.
The permissible range of air temperatures at the unit location
is between +5 and +40 °C.
The unit’s foundation must be suciently strong, horizontal
and stable enough to hold the weight of the unit. Weight
information and dimensions are listed on the nameplate and
in the relevant product documentation.
Install the units in such a way to leave enough space for
maintenance and repairs.
Sucient lighting should be provided for safe operation of
the unit.
The distance from the unit to an obstacle must be at least
equivalent to the height H (Fig. 8.1).
9 Mounting
9.1 Unpacking
• Care should be taken while unpacking the unit in
order not to cause any damage to the equipment.
• No person should walk or step over the equipment
because it can generate an accident or a risky situation
(Fig. 9.1).
1. Deliver the unit to the installation site in the original
packaging. Ensure that there is no damage to the packaging
(Fig. 9.2).
Fig. 9.1
Fig. 9.2
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Fig. 8.1

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Fig. 9.4
2. Remove the fasteners of the wooden frame (Fig. 9.3).
3. Remove the wooden frame.
4. Remove the protective film.
5. Check the contents of the packaging for completeness.
6. Check the unit for damage.
9.2 Check the factory pressure
Check the excess pressure. The equipment is delivered with
approximately 1-2 bar pressure. A pressurized unit indicates
that the refrigerant circuit is tight (Fig. 9.4).
The information on any damage, missing parts or lack of
excess pressure must be immediately reported to the
delivering carrier and the supplier of the equipment in
writing.
9.3 Installation
1. Follow these rules for mounting the unit:
• The unit must be mounted level. The dierence
from the horizontal must not be more than 3 mm per
1 m (Fig. 9.5).
• Fasten the unit to the foundation only at the
fastening points provided for that.
• If it is necessary to reduce vibrations and noise,
use anti-vibration mountings.
2. Mounting holes are out of the dimensions of the unit.
Marking and making holes are possible after placement of
the unit.
3. Place the unit on the foundation.
4. Fix the unit in its position. Use all the provided fastening
points. Check whether the unit is installed horizontally by
means of a level. Protect the fastenings against loosening
by means of an appropriate locking device. The nuts must
be tightened equally to achieve a load distribution that is as
balanced as possible. The nuts must not be overtightened
or stripped.
Fig. 9.3
Fig. 9.5

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9.4 Connection of pipelines of refrigerant circuit
1. It is recommended to connect pipelines to the unit in
accordance with EN 378 and the regulations in force in
the country where the unit is installed. Refer to the project
documentation in order to connect piping.
2. Only use pipes that have sucient strength and are clean
and dry inside and outside.
3. Pipelines should be laid in accordance with the general
rules and regulations for the installation of pipelines for
refrigeration systems. Integration and pipeline installation of
the unit in the system must be carried out in such a way that
penetration of liquid into the compressor is impossible. The
suction line should be sized to ensure good oil return. Avoid
flash gas in the liquid line.
4. Every refrigeration system is dierent so the pipe sizes
may dier from the unit’s connection sizes. Pipework to
and from the unit should be selected to suit the application
and not the connection size of the unit. Pipe sizes must be
determined according to good engineering practices.
5. Relieve the pressure before starting work. All shut-o
valves must be open. The overpressure relief is carried out
through the service valves.
After having released the excess pressure, connect the unit
to the system as soon as possible to prevent moisture and
contaminants from entering the system.
6. Connect the liquid line and the suction line.
Service valves located on the outside of the housing allow the
pipes to be fixed in any direction. For convenience of carrying
out soldering work and excluding damage to the protective
layer of the paint unit, the valves can be removed. When
reinstalling it is recommended to replace the valve gaskets.
7. Secure the pipelines on supporting structures. The
fastening must be carried out without disrupting the integrity
of the pipes.
8. If, after connecting the pipelines to the unit, the
refrigeration system is not mounted and the installation is
to be suspended for a long period of time, it is necessary to
solder the plugs, to evacuate and fill the refrigerant circuit
with dry nitrogen or other inert gas to an overpressure of 1-2
bars, verify the tightness of the installed contour and close
the valves on the body of the unit.
In case of improper pipeline connections
there is a danger of liquid leaks during
operation of the system. This may lead to
injuries and serious malfunctions.
When performing brazing operations, make
sure that the flame nozzle is not aimed
towards sensitive components in order to
avoid overheating. Use a safety screen if
necessary. It is permissible to cover sensitive
components with a wet cloth.
After incorporation of the unit into the system,
the safety risks of the unit should be rerated.
9.5 Connection of pipelines of chilled water loop
1. It is recommended to connect pipelines to the unit in
accordance with the regulations in force in the country where
the unit is installed. Refer to the project documentation in
order to connect piping.
2. Only use pipes that have sucient strength and are clean
and dry inside and outside.
3. Pipelines should be laid in accordance with the general
rules and regulations for the installation of pipelines.
4. The choice of pipe diameters is determined when
designing a chilled water loop. The diameters of the pipelines
may not coincide with the connecting diameters of nozzles
for threaded connection of the units to chilled water loop.
5. Connect the chilled water loop.
The unit has two nozzles for threaded connection. The
connecting dimensions are given in the technical catalog and
the catalog sheet on the OA331 unit at ostrov.com.
6. Secure the pipelines on supporting structures. The
fastening must be carried out without disrupting the integrity
of the pipes.
9.6 Electrical connection
The units are designed for operation from an electrical
network, the parameters of which are indicated in the
technical documentation and on the nameplate. The
deviation from the rated voltage should not exceed ± 10%.
1. It is recommended to make electrical connections in
accordance with EN 60204-1 and the regulations in force
in the country where the unit is installed. These operating
instructions and the enclosed wiring diagram must be
strictly followed.
2. When carrying out electrical connections, pay attention
the following:
• use cables with copper conductors only;
• the cross-section of the cables must be in
accordance with the maximum current consumption
of the unit;
• minimize cable length observing the required
bending radii;
• lay the cables in a position so that it is protected
from impacts and heat sources;
• do not fit power supply cables and control cables
in the same raceways or ducts;
• connect the cables to the terminal box or control
cabinet using bottom entry;
• the cables must not be damaged or twisted;
• equip the power supply system with appropriate
overcurrent protection devices.
3. Carefully read the wiring diagram.
4. Make sure that the power supply is disconnected and
there is no voltage in the circuit.
5. Attach the “DO NOT SWITCH ON!” label.
6. Carry out all electrical connections according to the
wiring diagram.
7. A power supply cable, a control cable and a grounding
conductor have to be used for connection of the unit.

10 Commissioning
Before commissioning of the unit, follow the following
instructions:
• check that the unit has been installed correctly and
in the correct location;
• check that the unit is properly fixed to the
foundation;
• check that all valves of the system are fully opened;
• check all refrigerant and chilled water loop
connections;
• check all electrical connections;
• check that the unit is grounded;
• check that the supply voltage is within the upper
and lower limits of the unit;
• check that the access to the power supply switch
of the machine room is free and clear of obstacles;
• check that the cover of the terminal box (door of
the control cabinet) is closed.
The unit is ready for use only after all of these instructions
and warnings have been scrupulously followed.
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Do not leave the unit unattended until the
system has reached normal operating
conditions.
10.1 Connection to the circuit of the refrigeration
system
The manifold is connected to the service valves (indicated by
the «P» index on the P&I Diagram). All subsequent operations
with the refrigeration system circuit are performed using the
connection data.
10.2 Tightness test pressure
1. Test the refrigerant circuit for leaks according to EN 378-2
and the regulations in force in the country where the unit is
installed. The leak test should be carried out by pressurizing
the system with nitrogen or another suitable inert gas,
with all valves in the system open.The whole circuit of the
refrigeration system must be tested. Never pressurize the
refrigerant circuit with oxygen or dry air as it can cause fire
or explosion. The required testing pressure depends on the
refrigerant used as well as on the system design. It is strictly
prohibited to perform welding or brazing work as well as
tighten screw connections on equipment under pressure.
If leaks are found, relieve the pressure, make repairs as
necessary and repeat the leak detection
2. Release the excess pressure.
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10.3 Vacuum procedure
Evacuate the system to remove any moisture or air. A
vacuum pump must be used for the evacuation.
Never use the compressor to evacuate the system or start
the compressor when it is under vacuum.
Evacuate the system to 1.5 ÷ 2 mbar absolute pressure.
Failure to reach this value during a sucient period
indicates a lot of moisture or a small leak. In this case,
to purge the moisture, pressurize the system with dry
nitrogen or another neutral gas. If there are no leaks,
continue evacuating the system until the required vacuum
is obtained
.
10.4 Charge by a refrigerant
The units are designed for compression HFC and HFC/HFO
refrigerants. Usage of refrigerant is permitted only after prior
written consent of the manufacturer.
Before starting work, make sure that the refrigerant charge
is suitable for this unit. Adding foreign substances to the
refrigerant or using a dierent refrigerant can cause an
emergency.
It is necessary to fill only the amount of refrigerant that the
refrigeration system is designed for. Excess refrigerant can
lead to a significant increase in the condensation temperature
and, in some cases, to a hydraulic shock, and its disadvantage
is the compressor’s overheating.
The refrigerant receiver must be filled with a refrigerant by no
more than 90% at a temperature of 20 °C
Charge the system with refrigerant in liquid phase only.
Refrigerant should be charged into the liquid line. Never
add liquid refrigerant to the suction side as this may lead to
penetration of liquid into the compressor. During charging,
the compressor must be switched o.
There should be no direct heating of the refrigerant cylinder
by open flames, radiant heaters, direct contact heaters etc. to
increase the flow velocity of the refrigerant.
If the maximum permissible refrigerant charge of the system
has been exceeded and the necessity arises to transfer part
of the refrigerant charge to refrigerant balloon, take care that
the maximum charge for each balloon is never exceeded.

17
ostrov.com
10.5 Changing the chilled water loop
1. Selection of heat transfer fluid
In cases where the pipeline of сhilled water loop is laid in
places where the ambient temperature can drop below
0 °C, measures must be taken to prevent the heat transfer
fluid from freezing.
The use of aqueous solutions of glycol is the most eective
protection against freezing of the system.
The concentration of glycol solutions is selected at the
lowest possible ambient temperature.
2. Before refueling, refer to Appendix 1 «Requirements for
heat transfer fluids for chilled water loop».
3. Fill the сhilled water loop and make sure it is sealed.
4. If necessary, remove air from the system.
10.6 Start up
When the unit is first started, especially during the cold
season or after a long period of standing, make sure that the
oil temperature in the compressor crankcase exceeds 10 °C
and there is no dissolved refrigerant in the oil.
1. Turn on all the protection circuit breakers.
2. Check the external control system. Set the desired
temperature in the cooled volume.
3. Set the power supply switch located on the terminal box
to «I» position (Fig. 10.1).
After the start-up of the unit, the following must be checked:
• The value of the starting currents of the compressor.
Starting currents are indicated on the assembly
compressor nameplate and in the OA331 technical
catalog on ostrov.com.
• Check that the suction pressure drops and the
discharge pressure rises.
• Ensure that the heat transfer fluid circulates through
the water-cooled condenser.
Fig. 10.1

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11 Operation
The unit is intended for automatic operation. Switching on/
o the unit is carried out by the signal from the external
control system.
The circuit of the refrigeration system must be designed,
operated, maintained, decommissioned for a prolonged
period and decommissioned before disposal, so that the
maximum allowable pressure can not be exceeded in any
part of the refrigeration system.
During operation, the unit must be regularly inspected. The
inspection intervals should be determined by the owner
or operator depending on the refrigerant used and the
operating mode of the system.
The following operating data must be checked:
• evaporating temperature;
• suction gas superheat;
• discharge gas temperature;
• condensing temperature;
• temperature of the heat transfer fluid of the chilled
water loop at the inlet and outlet;
The maximum allowable pressure on both
the high and low pressure sides as well as
the pressure in the сhilled water loop must
not be exceeded.
ostrov.com
10.7 Check after the unit is operational
After the unit has reached normal operating conditions,
perform the following checks:
• Ensure that there are no extraneous noises and
abnormal vibrations.
• Check the refrigerant level. Сheck is performed
according to the value of supercooling liquid refrigerant
and superheated suction gas. Add refrigerant if
necessary. Refrigerant should be refueled only in the
liquid phase, in the liquid line. It is forbidden to refuel the
refrigerant with the suction side to prevent liquid from
entering the compressor suction cavity.
• Check the operating current of the compressor and
pump.
• Check the suction pressure, the discharge pressure
and the pressure in the liquid line.
• Check the suction gas superheat at the unit inlet.
Operation of the unit at low values of superheated
suction gas can lead to failure of the compressor.
• Check the number of starts of the compressor per
hour. The number of starts should be no more than 6-8
times per hour.
• liquid subcooling;
• refrigerant charge. Сheck is performed according
to the value of supercooling liquid refrigerant and
superheated suction gas. If necessary, add or drain
refrigerant;
• compressor switching frequency;
• vibration and noise;
• visual inspection of power cables and electrical
connections.
Always compare these data with previous measurements. In
case of greater deviations, the source of the problem must
be determined and eliminated.

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12 Shutdown
In order to perform a normal shutdown of the unit, carry out
the following:
1. Stop the operation of the unit by the control system. The
compressor and pump will stop automatically.
2. Turn o power (Fig. 12.1).
An emergency shutdown is carried out by turning o
power (Fig. 12.1).
ostrov.com
Fig. 12.1
13 Maintenance
In order to maintain the required parameters and operating
modes of the refrigeration system, maintenance of the unit
must be regularly performed.
Maintenance work may be carried out by either skilled
personnel in possession of the required qualifications or a
licensed company.
During maintenance, perform the following checks:
• no leaks, mechanical damage, corrosion, dust, and
dirt are present;
• the work of control and protection devices;
• the insulation of cables and wires is not damaged.
If the pipelines of the system have been opened, the
refrigerant circuit should be evacuated to remove moisture.
It is strictly prohibited to perform welding
or brazing work as well as tighten screw
connections on equipment under pressure.

20
Maintenance checklist
m - monthly, y – once a year
Maintenance work
Interval
my
Visual inspection of unit for dirt deposits, rust and mechanical damage. +
Unit components and pipelines. Check and tightening of screw connections and
fastenings to frame. +
Check pipelines for leaks. +
Check state of thermal insulation. +
Check fastenings of unit. If fastenings are loose, tighten them. +
Monitoring of the functioning of the pump for chilled water loop. Check of the
starting and operating current of the pump motor. +
Performing chemical analysis of heat transfer fluids (Appendix 1). +
Cleaning unit of dust and dirt. +
Control of electrical connections, tightening if necessary. Checking wires for kinks
and wear. Checking wire insulation for damage and discoloration. +
Check supply voltage. +
Compressor. Measuring start-up and operating current. +
Checking the monitoring and protection devices. +
Check grounding resistance. +
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