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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 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.
15.Refrigerant 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).
-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.
16.Decommissioning
Before carrying out this procedure, it is essential that the technician is completely
familiar with the equipment and all its details. It is a 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 reuse of reclaimed
refrigerant. It is essential that electrical power is available before the task is
commenced.
Become familiar with the equipment and its operation.
b) Isolate system electrically.
