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- 12 -
09/2020
Copyright © 2020, Fast ČR, a.s.
SERVICING INSTRUCTIONS
1.1 Area check
Before starting work on asystem containing flammable refrigerants, safety checks are
necessary to ensure that the risk of ignition is minimized. When repairing acooling
system, the following measures must be adhered to prior to performing any work.
1.2. Work procedure
Work must be performed following a controlled procedure so that the risk of
flammable gases or fumes being present during this time is minimised.
1.3 General work area
The whole maintenance crew and other personnel at the site must be informed about
the nature of the works being performed. Work in tight areas must be prevented. The
area around the work site must be divided into sections. It must be ensured that the
conditions inside the area are safe by means of inspections of flammable materials.
1.4 Check for presence of arefrigerant
The area must be checked using an appropriate detector for the presence of refrigerant
before and during work to ensure that technicians are aware of apotentially flammable
atmosphere. It must be ensured that the device used for the detection of leaks is
suitable for use on flammable refrigerants, i.e. non-sparking, appropriately sealed or
intrinsically safe.
1.5 Presence of afire extinguisher
In the event that any work is performed on the cooling device or associated parts
under heat, then asuitable fire extinguisher must be on hand. In the vicinity of the
filling area, there must be apowder or CO
2
fire extinguisher.
1.6 No ignition sources
No person performing work related to the cooling system that encompasses the
uncovering of any pipes that contain or have contained flammable gasses may
use any ignition sources in amanner that could lead to a fire or explosion hazard.
All possible ignition sources, including the smoking of cigarettes should be kept at
asufficient distance from the installation, repair, removal or disposal location, during
which flammable refrigerant could potentially be released into the surrounding
environment. Prior to starting work, the area around the appliance must be checked
to ensure that there are no fire hazards or ignition risks present. A"smoking forbidden"
sign must be installed.
1.7 Ventilated area
It must be ensured that the area is ventilated or appropriately ventilated prior to
penetrating the system or performing any work under heat. The intensity of ventilation
must continue for the time that works are performed. Ventilation should safely
dissipate any released refrigerant and draw it out into the atmosphere as apriority.
1.8 Cooling system checks
In places where electrical components are replaced, these components must be suitable
for this purpose and conform to correct specifications. The manufacturer'sinstructions
for maintenance and service must always be followed. If any doubts arise, it is
necessary to request help from the manufacturer'stechnical department.
On installations containing flammable refrigerants, it is necessary to perform the
following checks:
– the amount of refrigerant corresponds to the size of the room in which components
containing refrigerant are installed;
– ventilation systems and outlets are in full working order and are not clogged;
– if any indirect cooling circuit is used, the second circuit must be checked for the
presence of refrigerant;
– the markings on the appliance must remain constantly visible and legible, and
marking and signs that are illegible must be repaired;
– The cooling pipes and components are installed in locations where it is not probable
that they will be exposed to any substances that could corrode the parts containing
refrigerant, unless these components are built using materials that are inherently
resistant to corrosion or are appropriately protected against corrosion.
1.9 Electrical device check
The repair and maintenance of electrical components must include safety checks and
inspections of components.
In the event of a malfunction that could affect safety, no electrical power may be
connected to the circuit until the malfunction is satisfactorily resolved. In the event
that the malfunction cannot be immediately repaired but it is necessary to continue
running the appliance, an appropriate temporary solution must be used. The owner of
the appliance must be informed in such away that all parties know about it.
The initial safety check must ensure:
■ that capacitors are discharged: this must be performed in asafe way to prevent the
possibility of sparking;
■ that no electrical components or wiring is uncovered during the process of filling,
draining or cleaning the system;
■ that the grounding is not interrupted.
2. Repair of sealed components
When repairing sealed components, all the electrical power supply must be
disconnected from the appliance on which work is being performed before sealed
lids, etc. are removed. When it is absolutely necessary to have live power supply going
into the appliance while servicing the appliance, it is necessary to install apermanent
device in the most critical point to detect leakage so that a dangerous situation is
averted.
Special attention must be paid to ensuring that as aresult of the work performed on
electrical components the cover is not changed to the extent of affecting the level of
protection. This must also include damage to cables, excessive number of connections
and terminals not performed according to original specifications, damaged gaskets,
incorrect configuration of plugs, etc.
It is necessary to ensure that the appliance is mounted safely.
It is necessary to ensure that gaskets or sealing materials are not damaged in such
away that they no longer serve to prevent the entry of aflammable atmosphere. Spare
parts must conform to the manufacturer'sspecifications.
NOTE:
The use of silicone gaskets and seals may suppress the efficiency of
certain type of leak detection devices. Intrinsically safe components do
not need to be disconnected prior to being worked on.
3. Repairs of intrinsically safe components
No permanently inductive or capacitative load may be placed on the circuit without it
being ensured that thereby the permitted voltage and current for the used appliance
is not exceeded.
Intrinsically safe components are the only type on which it is possible to work in
aflammable environment even while under live current. Testing equipment must have
correct specifications.
Parts are replaced using only parts specified by the manufacturer. Different parts could
result in ignition of refrigerant upon leakage into the environment.
4. Cabling
Check that cabling is not exposed to wear and tear, corrosion, excessive pressure,
vibrations, sharp edges or any other negative environmental effects. This check must
also take into consideration the effects of ageing and permanent vibrations from
sources such as compressors or fans.
5. Detection of flammable refrigerants
Under no circumstances may potential sources of ignition be used for locating or
detecting refrigerant leaks.
Ahalogen burner (or any other type of detector utilising an open flame) must not be
used.
6. Leak detection methods
The following leak detection methods are considered acceptable for systems
containing flammable refrigerants.
For the detection of flammable refrigerants, electronic leak detectors must be used,
however their sensitivity may not be appropriate or they may require recalibration.
(Detection equipment must be calibrated in an area without any refrigerant present).
It is important to ensure that the detector is not apotential ignition source and that
it is suitable for the used refrigerant. The leak detector must be set to apercentage of
LFL refrigerant and must be calibrated for the used refrigerant and the respective gas
percentage is confirmed (maximum 25%).
Leak detection liquids are suitable for use on most refrigerants, however, detergents
containing chlorine must be excluded since chlorine may react with the refrigerant
and corrode copper pipes.
In the event of asuspected leak, all open flames must be removed/extinguished.
In the event that the refrigerant leak is found and requires hard soldering, then all
the refrigerant must be drained from the system or separated (by closing avalve) in
apart of the system distant from the leak. The system must then be cleaned out using
oxygen-free nitrogen (OFN) both before as well as after the hard soldering process.
7. Collection and pump discharge
In the event that the cooling circuit is breached due to repairs – or for any other reason
– conventional procedures must be followed. It is, however, important to adhere to the
best method due to flammability. It is necessary to adhere to the following procedure:
■ collect the refrigerant;
■ clean out the circuit using inert gas;
■ pump out;
■ again clean out using inert gas;
■ open the circuit by cutting or hard soldering.
The contents of the circuit must be collected into correct collection cylinders. The
system must be "flooded" with OFN (oxygen-free nitrogen) for the unit to remain
safe. It may be necessary to repeat the procedure several times. For this task, neither
compressed air nor oxygen may be used.
Flooding may be achieved by disrupting the vacuum in the system with the use of
OFN, and by continued filling until the operating pressure is achieved, then venting
into the atmosphere and finally lowering to avacuum. This process must be repeated if
refrigerant still remains in the system. When the last OFN cartridge is used, the system
must be ventilated to atmospheric pressure to enable work to be performed. This
activity is absolutely necessary if hard soldering is to be performed on the pipes.
It is necessary to ensure that the vacuum pump outlets are not nearby to any ignition
source, and ventilation must be provided.
8. Filling procedure
Apart from conventional filling procedures, also the following requirements must be
adhered to.
– It is necessary to ensure that no contamination by various refrigerants occurs when
the filling device is used. Hoses or pipes must be as short as possible to minimise the
amount of refrigerant contained inside of them.
– Cylinders must be held vertically.
– It is important to ensure that the cooling system is grounded prior to being filled
with refrigerant.
– When filling is complete, the system must be marked with alabel (if it does not have
one already).
– It is necessary to pay extreme care to ensure that the cooling system is not overfilled.
Apressure test using OFN must be performed before refilling the system. In the case
of a leak, the system must be tested after being refilled but also before being put
into operation. Averification test must be performed before leaving the installation
location.
9. Taking out of operation
Prior to performing this procedure it is essential that the technician fully acquaints
him/herself with the device and all its particulars. Correct practice of safely collecting
all refrigerant is recommended. Prior to performing this activity, oil and refrigerant
samples must be taken if an analysis is required prior to using the using the
regenerated refrigerant for the first time. It is essential that prior to starting this activity
that electricity is available.
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