Important Safety Information
READ AND FOLLOW ALL SAFETY INSTRUCTIONS
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 the best practice is followed since fl ammability
is a consideration. The following procedures 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 fl ushed 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 fi ll until the working pressure is achieved, then
venting to atmosphere and fi nally pulling down
to a vacuum. This process shall be repeated until
no refrigerant is within the system. When the
fi nal OFN charge is used, the system shall be
vented down to atmospheric pressure to enable
work to take place. This operation is absolutely
vital is brazing operations on the pipe-work are
to take place.
• Ensure that the outlet for the vacuum pump is
not close to any ignition sources and there is
ventilation available.
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 minimize the amount of refrigerant
contained in them.
• Cylinders shall be kept upright.
• Ensure that the refrigeration system is earthed
prior to charging the system with refrigerant.
• Label the system when charging is complete, if
not already labeled.
• Extreme care shall be taken not to overfi ll the
refrigeration system.
• Prior to recharging the system it shall be
pressure tested with OFN. The system shall be
leak tested on completion of charging but prior
to commissioning. A follow up leak test shall be
carried out prior to leaving the site.
Cabling
Check that cabling will not be subject to wear,
corrosion, excessive pressure, vibration, sharp
edges or any other adverse environmental effects.
The check shall also take into account the effects of
aging or continual vibration from sources such as
compressors or fans.
Detection of fl ammable 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 fl ame shall not be used.
Leak detection methods
The following leak detection methods are deemed
acceptable for systems containing fl ammable
refrigerants:
• Electronic leak detectors shall be used to detect
fl ammable 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 confi rmed.
• Leak detection fl uids 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 or pipe-work.
• If a leak is suspected, all naked fl ames shall be
removed or extinguished.
• If 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.
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