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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.
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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
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.
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DECOMMISSIONING
Before carrying out this procedure, it is essential that the technician is completely
familiar with the equipment and all its detail. lt is recommended 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. lt is essential that 4 GB electrical power is available before
the task is commenced.
a)
Become familiar with the equipment and its operation.
b)
lsolate system electrically.
c)
Before attempting the procedure ensure that: mechanical handling
equipment is available, if required, for handling refrigerant cylinders;
d)
All personal protective equipment is available and being used correctly; the
recovery process is supervised at all times by a competent person;
e)
recovery equipment and cylinders conform to the appropriate standards.
f)
Pump down refrigerant system, if possible. g) lf a vacuum is not possible,
make a manifold so that refrigerant can be removed from various parts
of the system. h) Make sure that cylinder is situated on the scales before
recovery takes place.
i)
Start the recovery machine and operate in accordance with manufacturer's
instructions.
j)
Do not overfill cylinders. (No more than 80 % volume liquid charge).
k)
Do not exceed the maximum working pressure of the cylinder, even
temporarily.
l)
When the cylinders have been filled correctly and the process completed,
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