Saneo JHS-A19-07KR2/E Mode D'emploi page 51

Leak detection methods
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The following leak detection methods are considered acceptable for systems containing
flammable refrigerants.
Electronic leak detectors must be used to detect flammable refrigerants, but their sensitivity may
not be adequate or may require recalibration. (Detection equipment must be calibrated in an
area without refrigerant.) Ensure that the detector is not a potential source of ignition and is
suitable for the refrigerant used. The leak detection equipment must be set to a percentage LFL
of the refrigerant and must be calibrated to the fluid used and the appropriate percentage of gas
(maximum 25%) is confirmed.
Leak detection fluids are suitable for use with most refrigerants, but the use of detergents
containing chlorine should be avoided as chlorine can react with the refrigerant and corrode the
copper piping.
In the event of a suspected leak, all open flames must be eliminated/extinguished.
If a refrigerant leak is found and brazing is required, all the refrigerant in the system must be
recovered or isolated (by means of shut-off valves) in a part of the system remote from the leak.
The oxygen-free nitrogen must then be purged through the system both before and during the
brazing process.
Removal and evacuation
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When working on the refrigerant circuit for repairs - or for any other purpose - conventional
procedures must be used. However, it is important to follow best practice as flammability is a
concern. The following procedure must be followed:
- remove the refrigerant;
- purge the circuit with an inert gas;
- evacuate;
- purge again with an inert gas;
- open the circuit by cutting or soldering.
The refrigerant charge must be collected in correct recovery bottles. The system must be drained
with oxygen-free nitrogen to make the element safe. This process may have to be repeated
several times. Do not use compressed air or oxygen for this task.
Drainage must be achieved by cutting the vacuum in the system with oxygen-free nitrogen and
continuing to fill until the operating pressure is reached, then venting into the atmosphere and
finally creating the vacuum. This process must be repeated until there is no refrigerant left in the
system. When the final oxygen-free nitrogen charge is used, the system must be returned to
atmospheric pressure to allow operations to proceed. This operation is absolutely vital if brazing
operations are to take place on the pipes.
Make sure that the outlet of the exhaust pump is not close to an ignition source and that there is
ventilation.