22
7. 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 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 ventilation available.
8. 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.
9. 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 available before the
task is commenced.
15429_Dimplex DPRC40U Manual.indd 22
15429_Dimplex DPRC40U Manual.indd 22
9/09/20 6:40 PM
9/09/20 6:40 PM
