Obelink CA-3000 Anleitung Seite 109

For appliances containing flammable refrigerants, refrigerants
purging shall be achieved by breaking the vacuum in the system
with oxygen-free nitrogen 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 oxygen-free
nitrogen charge is used, the system shall be vented down to
atmospheric pressure to enable work to take place. This ope-
ration is absolutel 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 potential ignition sources and that ventilation is
available.
16. 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 equip-
ment.Hoses or lines shall be as short as possible to minimize
the amount of refrigerant contained in them. Cylinders shall be
kept in an appropriate position according to the instructions.
Ensure that the refrigerating 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 refrigerating system. Prior to recharging the system,
it shall be pressure-tested with the appropriate purging gas. 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.
17. Decommissioning
Before carrying out this procedure, it is essential that the techni-
cian is completely familiar with the equipment and all its detail.
It is recommended good practice that all refrigerants are reco-
vered safely. Prior to the task being carried out, an oil and refri-
gerant sample shall be taken in case analysis is required prior
to re-use of recovered refrigerant. It is essential that electrical
power is available before the task is commenced.