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Warnings (for using R290 refrigerant only)
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 ventilation available.
13. 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. A follow up leak test shall be carried out prior to
leaving the site.
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