10
Safety Precautions
8. Charging procedures
•
In addition to conventional charging
procedures, the following requirements shall
be followed.
-
Ensure that contamination of diff erent
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 in an appropriate
position according to the instructions.
-
Ensure that the refrigerating system is
earthed prior to charging the system with
refrigerant.
-
Label the system when charging is
complete (if not already labelled).
-
Extreme care shall be taken not to over fill
the refrigerating system.
•
Prior to recharging the system it shall be
pressure tested with OFN (refer to #7).
•
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.
•
Electrostatic charge may accumulate and
create a hazardous condition when charging
and discharging the refrigerant. To avoid fi re
or explosion, dissipate static electricity during
transfer by grounding and bonding containers
and equipment before charging/discharging.
7. Refrigerant removal and circuit
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 fl ammability is a consideration.
The following procedure shall be adhered to:
1) Safely remove refrigerant following local
and national regulations
2) Evacuate
3) Purge the circuit with inert gas
4) Evacuate
5) Continuously fl ush with inert gas when
using fl ame to open circuit
6) Open the circuit
•
The refrigerant charge shall be recovered into
the correct recovery cylinders.
•
Compressed air or oxygen shall not be used
for purging refrigerant systems, only use OFN
(oxygen free nitrogen) for this task.
•
Purging of the refrigerant circuit shall be
achieved by breaking the vacuum in the
system with inert gas and continuing to fi ll
until the working pressure is achieved, then
venting to atmosphere, and fi nally pulling
down to vacuum.
•
This process shall be repeated until no
refrigerant is within the system.
•
The system shall be vented down to
atmospheric pressure to enable work to take
place.
•
Ensure that the outlet of the vacuum pump is
not close to any potential ignition sources and
there is ventilation available.
OFN = oxygen free nitrogen, type of inert gas.
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