HTW HTWD020A3 Manual De Usuario E Instalacion página 41

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.
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 minimized 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.
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
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