Qlima WDH 224 PTC Manuel D'utilisation page 105

also take into account the effects of aging or continua! vibration from sources
such as compressors or fans.
5 DETECTION OF FLAMMABLE REFRIGERANTS
Under no circumstances shall potential sources of ignition be used in the searching
for or detection of refrigerant leaks. A halide torch (or any other detector using a
naked flame} shall not be used.
6 LEAK DETECTION METHODS
The following leak detection methods are deemed acceptable for systems
containing flammable refrigerants. Electronic leak detectors shall be used to
detect flammable refrigerants, but the sensitivity may not be adequate, or may
need recalibration. (Detection equipment shall be calibrated in a refrigerant-free
area.)
Ensure that the detector is not a potential source of ignition and is suitable for
the refrigerant used. Leak detection equipment shall be set at a percentage of the
LFL of the refrigerant and shall be calibrated to the refrigerant employed and the
appropriate percentage of gas (25 % maximum} is confirmed.
Leak detection fluids are suitable for use with most refrigerants but the use of
detergents containing chlorine shall be avoided as the chlorine may react with the
refrigerant and corrode the copper pipework.
lf a leak is suspected, all open flames shall be removed/extinguished.
lf a leakage of refrigerant is found which requires brazing, all of the refrigerant
shall be recovered from the system, or isolated (by means of shut off valves} in a
part of the system remote from the leak. Oxygen free nitrogen (OFN) shall then
be purged through the system both before and during the brazing process.
7 REMOVAL AND EVACUATION
When breaking into the refrigerant circuit to make repairs - or for any other
purpose - conventional procedures shall be used. However, it is important that
best practice is followed since flammability is a consideration. The following
procedure shall be adhered to: remove refrigerant; purge the circuit with inert
gas; evacuate; purge again with inert gas; open the circuit by cutting or brazing.
The refrigerant charge shall be recovered into the correct recovery cylinders. The
system shall be "flushed" with OFN to render the unit safe. This process may need
to be repeated several times. Compressed air or oxygen shall not be used for this
task. Flushing shall be achieved by breaking the vacuum in the system with OFN
and continuing to fill until the working pressure is achieved, then venting to
atmosphere, and finally pulling down to a vacuum. This process shall be repeated
until no refrigerant is within the system.
When the final OFN charge is used, the system shall be vented down to
atmospheric pressure to enable work to take place. This operation is absolutely
vital if brazing operations on the pipework are to take place. Ensure that the
outlet tor the vacuum pump is not close to any ignition sources and !here is
ventilation available.
8 CHARGING PROCEDURES
In addition to conventional charging procedures, the following requirements shall
be followed. Ensure that contamination of different refrigerants does not occur
when using charging equipment. Hoses or lines shall be as short as possible to
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