Fral FSC25HP.4.3001 Manuel Technique page 35

7.5 Leak detection methods
7.6 Removal and evaluation (flushing)
7.7 Charging procedures
7.8 Decommissioning
The following methods of detecting spills are believed to be acceptable for systems that contain
flammable refrigerant fluids.
Electronic leak detectors should be used to detect the presence of flammable refrigerant fluids, but
their sensitivity may not be adequate or may need to be re-calibrated. (The detection equipment
must be calibrated in an area without refrigerant fluid). Make sure that the detector is suitable for
operating in an Atex atmosphere (at least zone 2), that it is suitable for the refrigerant fluid used.
The detection equipment must be set at a percentage of the LFL of the refrigerant fluid and must be
calibrated for the refrigerant fluid used, and the appropriate percentage of gas (maximum 25%)
must be confirmed.
| Fluid leak detectors are suitable for use with most refrigerant fluids but the use of detergents that
contain bleach must be avoided as they can react with the refrigerant fluid and corrode the copper
piping network.
If a leak of refrigerant fluid is found that requires repair with hot work (e.g. brazing) it is necessary to
proceed with an accurate flushing procedure with inert gas, according to the indications given in the
following point.
When performing maintenance operations on parts of the refrigerant circuit that do not provide for
the use of ignition sources and / or hot work, conventional procedures can be followed. If, on the
other hand, interventions involving the use of ignition sources and / or hot work must be carried out,
or if it is not possible to establish a priori the nature and extent of the maintenance operations to be
performed, it is necessary to proceed with the complete removal of the refrigerant gas and
reclamation, through a procedure called "flushing".
- remove the refrigerant fluid by means of a vacuum pump, transferring it to suitable containers
(cylinders);
- Add the inert gas (OFN: Oxygen Free Nitrogen) using the vacuum condition present, taking
care to check that all parts and components of the circuit are in a condition to receive the gas;
do not put the circuit under pressure with the inert gas, but return to atmospheric pressure
conditions;
- Open the circuit in one or more points so that the inert gas can be exhaled externally;
- Carry out the inert gas supply with the circuit open, in order to remove any traces of refrigerant
fluid still trapped inside.
The gas supply must be continued for a time that, depending on the flow of the aforementioned gas,
allows an overall "washing" of the inside of the circuit for 5 equivalent volumes.
At the end of this operation, maintenance activities can be carried out.
ATTENTION: INERT GAS OFN IS A NON-BREATHABLE FLUID (DANGER OF ASPHYXIA); THE
VENT IN THE ATMOSPHERE OF SUCH A FLUID MUST BE DONE AWAY FROM THE
OPERATOR.
- Make sure that when using a refill equipment, contamination between different refrigerant fluids
does not occur. | flexible hoses or pipes must be as short as possible to minimize the amount of
refrigerant contained in them.
- The cylinders must be kept upright.
- Make sure that the refrigeration system is grounded before proceeding to recharge the system
with the refrigerant fluid.
- Label the system when charging is complete, (if not already done).
- Particular care must be taken not to overload the refrigeration system.
Before recharging, the system must be subjected to the pressure test with OFN. The system must
undergo a leak test at the end of charging but before putting it into operation. An additional leak test
must be performed before leaving the site.
Before carrying out this procedure, it is essential that the technician is totally familiar with the
apparatus and all its details. It is good practice that all refrigerant fluids are safely stored. Before
M.FSC25HP.4.3001-01 Manual _ITA_UK_DE_FR_ES - 01/08/2023
EN
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