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ders. 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 for the vacuum pump is
not close to any ignition sources and there is
ventilation available.
CHARGING PROCEDURES
- In addition to conventional charging proce-
dures, the following requirements shall be
followed.
- Ensure that contamination of different refrig-
erants does not occur when using charging
equipment. Hoses or lines shall be as short as
possible to minimise 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).
- Extreme care shall be taken not to overfill 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.
DECOMMISSIONING
- Before carrying out this procedure, it is essen-
tial that the technician is completely familiar
with the equipment and all its detail. It is rec-
ommended good practice that all refrigerants
are recovered safely. Prior to the task being
carried out, an oil and refrigerant sample shall
be taken in case analysis is required prior to
re-use of reclaimed refrigerant. It is essential
that electrical power is available before the task
is commenced.
a) Become familiar with the equipment and its
operation.
b) Isolate system electrically.
c) Before attempting the procedure ensure that:
mechanical handling equipment is available, if
required, for handling refrigerant cylinders; all
personal protective equipment is available and
being used correctly; the recovery process is
supervised at all times by a competent person;
recovery equipment and cylinders conform to
the appropriate standards.
d) Pump down refrigerant system, if possible.
e) If a vacuum is not possible, make a mani-
fold so that refrigerant can be removed from
various parts of the system.
f) Make sure that cylinder is situated on the
scales before recovery takes place.
g) Start the recovery machine and operate in
accordance with manufacturer's instructions.
h) Do not overfill cylinders. (No more than 80 %
volume liquid charge).
i) Do not exceed the maximum working pressure
of the cylinder, even temporarily.
j) When the cylinders have been filled correctly
and the process completed, make sure that
the cylinders and the equipment are removed
from site promptly and all isolation valves on
the equipment are closed off.
k) Recovered refrigerant shall not be charged
into another refrigeration system unless it has
been cleaned and checked.
LABELLING
- Equipment shall be labelled stating that it has
been de-commissioned and emptied of refriger-
ant. The label shall be dated and signed.
- Ensure that there are labels on the equipment
stating the equipment contains flammable
refrigerant.
RECOVERY
- When removing refrigerant from a system,
either for servicing or decommissioning, it is
recommended good practice that all refrigerants
are removed safely. When transferring refriger-
ant into cylinders, ensure that only appropriate
refrigerant recovery cylinders are employed.
Ensure that the correct number of cylinders for
holding the total system charge are available.
All cylinders to be used are designated for the
recovered refrigerant and labelled for that refrig-
erant (i.e. special cylinders for the recovery of
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