Bosch CS 3000 AWP Installations- Und Bedienungsanleitung Seite 71

Reparation of intrinsically safe components
Do not apply permanent inductive or capacitive loads to the circuit
without making sure that they do not exceed the admissible voltage and
current allowed for equipment in use.
Intrinsically safe components are the only component type on which
operations can be performed in a flammable atmosphere. The testing
device must show a correct value. Replace components only with the
parts specified by the manufacturer.
Following a leak, other parts could lead to the combustion of the
refrigerant in the atmosphere.
Wires
Make sure wires are not subjected to wear, corrosion, excessive pressure
or vibration, that there are no sharp edges and that they do not produce
other negative effects on the environment. The inspection must also
keep into consideration the effects of tine or the continuous vibration
caused e.g. by compressors or fans.
Detection of flammable refrigerants
Under no circumstance is it allowed to use potential ignition sources to
search or detect refrigerant leaks.
Do not use halide lights (or any other open flame detectors).
Leak detection methods
The following leak detection methods are considered acceptable for
systems containing flammable refrigerants. Electric leak detectors must
always be used to identify flammable refrigerants, although they do not
present a suitable sensitivity level or require recalibration (detection
equipment must be calibrated in an area free from refrigerants).
Check that the detector is not a possible source of ignition and that it is
suitable for the refrigerant. Leak detection equipment must always be
set to an LFL percentage and calibrated depending on the refrigerant
used, so the correct gas percentage (25% max) must be verified.
Leak detection fluids are suitable for most refrigerants, although using
detergents containing chlorine should be avoided as this substance may
react with the refrigerant and corrode copper pipes.
If a leak is suspected, all open flames must be removed or switched off.
If a leak is identified that requires brazing, all the refrigerant must be
recovered from the system or isolated (using shut off valve) in a section
of the system far away from the leak. Oxygen-Free-Nitrogen (OFN) is
then purged through the system both before and during the brazing
procedure.
Removal and evacuation
When intervening on the refrigerant circuit to perform repair work or any
other type of work, always follow the normal procedure. However,
considering the risk of flammability, we recommend following the best
practices. Comply with the following procedure:
• Remove the refrigerant;
• Purge the circuit with inert gas;
• Evacuate;
• Purge again with inert gas;
• Interrupt the circuit with interruption or brazing.
The refrigerant charge must be collected in suitable recovery tanks.
To make the unit safe, flushing with Oxygen-free-Nitrogen must be
performed. This procedure may have to be repeated multiple times.
Do not use compressed air or oxygen for this operation.
The refrigerant charge must be collected in suitable recovery tanks.
To make the unit safe, flushing with Oxygen-Free-Nitrogen (OFN) must
be performed. This procedure may have to be repeated multiple times.
Do not use compressed air or oxygen for this operation.
Flushing is obtained interrupting the system vacuum with OFN and filling
until the operating pressure is obtained, then releasing into the
atmosphere and restoring the vacuum. This process must be repeated
until there is no trace of refrigerant in the system.
CS3000 AWP – 6721852570 (2022/11)
When using the final OFN charge, the system must be vented to the
atmospheric pressure to allow the intervention. This step is essential to
perform brazing operations on the pipes.
Make sure that the vacuum pump intake is not near ignition sources and
that there is suitable ventilation.
Charging operations
In addition to conventional charging operations, the following
requirements must be complied with:
• When using charging equipment, make sure that the various
refrigerants are not contaminated. Flexible tubes or conduits must be
as short as possible to reduce to the minimum the quantity of
refrigerant contained;
• Tanks must be kept in a vertical position;
• Before loading the system with refrigerant, check that the cooling
system is earthed;
• Label the system when fully charged (unless already labelled);
• Make sure not to fill the cooling system excessively;
• Before recharging the system, the pressure must be tested with OFN.
A leak test must be performed after the charging operations but
before commissioning. Before leaving the site, perform an additional
leak test.
Dismantling
Before performing this procedure, it is essential that the technician has
become familiar with the equipment and the relative details.
It is recommend employing good practices for a safe recovery of the
refrigerants.
Before performing the operation, take a sample of oil and refrigerant and
analyse it, before reusing the regenerated refrigerant. Also it is important
to check the availability of electricity.
Before attempting the procedure:
• Become familiar with the equipment and how it functions;
• Electrically isolate the system;
• The mechanical manipulation equipment is available, if necessary, to
handle refrigerant tanks;
• All the personal protection equipment is available and employed
correctly;
• The recovery procedure is monitored at all times by skilled personnel;
• The recovery equipment and tanks comply with suitable standards;
• If possible, pump the refrigerant system;
• If it is not possible to obtain a vacuum, make sure that a collector
removes the refrigerant from various parts of the system;
• Before proceeding with the recovery, check that the tank is located
on the scales;
• Start up the recovery machine and use it following the instructions by
the manufacturer;
• Do not fill the tanks excessively. (Do not exceed 80% of the liquid
volume);
• Do not exceed the tank's maximum operating pressure, not even
momentarily;
• Once the tanks are filled correctly and the process is over, make sure
that the tanks and equipment are immediately removed from the site
and that all insulation valves on the equipment are closed;
• The refrigerant recovered must not be loaded into another refrigerant
system unless it has been cleaned and checked.
Gas safety warnings (R32)
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