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.
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 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. Afollow up leak test shall be carried out prior to
leaving the site.
9.Decommissioning
Before carrying out this procedure, it is essential that the technician is
completely familiar with the equipment and all its detail. It 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. 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, forhandling
refrigerant cylinders;
•All personal protective equipment is available and being used
correctly;
•The recovery process is supervised at all times by a competent
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