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NOTE Examples of leak detection uids are
- bubble method,
- uorescent method agents.
If a leak is suspected, all naked ames shall be removed/extinguished.
If a leakage of refrigerant is found which requires brazing, all of the refrigerant shall
the system remote from the leak. See the following instructions of removal of
refrigerant.
7. Removal and evacuation
When breaking into the refrigerant circuit to make repairs - or for any other purpose
conventional procedures shall be used. However, for ammable refrigerants it is
important that best practice be followed, since ammability is a consideration.
The following procedure shall be adhered to:
safely remove refrigerant following local and national regulations;
evacuate;
purge the circuit with inert gas (optional for A2L);
evacuate (optional for A2L);
continuously ush or purge with inert gas when using ame to open circuit; and
open the circuit
The refrigerant charge shall be recovered into the correct recovery cylinders if
venting is not allowed by local and national codes. For appliances containing
ammable refrigerants, the system shall be purged with oxygen-free nitrogen to
render the appliance safe for ammable refrigerants. This process might need to
be repeated several times. Compressed air or oxygen shall not be used for purging
refrigerant systems.
For appliances containing ammable refrigerants, refrigerants purging shall be
achieved by breaking the vacuum in the system with oxygen-free nitrogen and
continuing to ll until the working pressure is achieved, then venting to atmosphere,
and nally pulling down to a vacuum (optional for A2L). This process shall be
repeated until no refrigerant is within the system (optional for A2L). When the nal
oxygen-free nitrogen charge is used, the system shall be vented down to
atmospheric pressure to enable work to take place.
The outlet for the vacuum pump shall not be close to any potential ignition sources,
and ventilation shall be available.
8. Charging procedures
In addition to conventional charging procedures, the following requirements shall
be followed:
Works shall be undertaken with appropriate tools only (In case of uncertainty,
please consult the manufacturer of the tools for use with ammable refrigerants)
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 over ll the refrigeration system.
Prior to recharging the system it shall be pressure tested with oxygen free nitrogen
(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. Recovery
When removing refrigerant from a system, either for servicing or decommissioning,
it is recommended good practice that all refrigerants are removed safely.
When transferring refrigerant into cylinders, ensure that only appropriate refrigerant
recovery cylinders are employed. Ensure that the correct number of cylinders for
holding the total system charge is available. All cylinders to be used are designated.
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