28-EN
27-EN
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EN
- 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 purging
refrigerant systems.
• Flushing shall be achieved by breaking the vacuum in the
system with OFN and continuing to
fi
ll until the working
pressure is achieved, then venting to atmosphere, and
fi
nally
pulling down to a vacuum.
• This process shall be repeated until no refrigerant is within the
system.
• When the
fi
nal 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 that 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 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 over
fi
ll the refrigeration
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
technician is completely familiar with the equipment and all its
details.
• 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 to reuse 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, for
handling refrigerant cylinders;
- All personal protective equipment is available and being used
correctly;
- The recovery process is supervised at all times by a
competent person;
- Recovery equipment and cylinders conform to the appropriate
standards.
d) Pump down refrigerant system, if possible.
e)
If a vacuum is not possible, make a manifold so that
refrigerant can be removed from various parts of the
system.
