[47]
EN
DEHUMIDIFIER
14. 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 crucial 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.
15. Refrigerant 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 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 commissioning. A
follow up leak test shall be carried out prior to leaving the site.
