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English
15. Removal and evacuation
When breaking into the refrigerant circuit to make repairs (or
for any other purpose) conventional procedures shall be used.
However, it is important that best practice is followed since
flammability is a consideration. The following procedure shall be
adhered to:
• Remove the refrigerant.
• Purge the circuit with inert gas.
• Evacuate.
• Purge again with inert gas.
• Open the circuit by cutting or brazing.
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 pipe-work
are to take place. Ensure that the outlet for the vacuum pump is not
close to any ignition sources and there is a ventilation 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 equipment. Hoses or lines shall
be as short as possible to minimise the amount of refrigerant
contained in them.
