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Removal and evacuation
When breaking into the refrigerant circuit to make repairs or for any other purpose, conventional
procedures shall be used. However, for flammable refrigerants it is important that the best prac-
tice is. Opening of the refrigeration systems shall not be done by brazing. The following procedure
shall be adhered to:
1. Remove refrigerant.
2. Purge the circuit with inert gas.
3. Evacuate.
4. Purge again with inert gas.
5. Open the circuit by cutting or brazing.
The refrigerant charge shall be recovered into the correct recovery cylinders. For appliances con-
taining FLAMMABLE REFRIGERANTS, 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 purging refrigerant systems.
For appliances containing FLAMMABLE REFRIGERANTS, 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 found 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 vital if
brazing operations on the pipework are to take place.
Ensure that the outlet for the vacuum pump is not close to any ignition sources and that venti-
lation is 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 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 the appropriate purging gas.
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 available
before the task is commenced.
1. Become familiar with the equipment and its operation.
2. Isolate system electrically.
3. Before attempting the procedure, ensure that:
- Mechanical handling equipment is available.
- All personal protective equipment is available and being used correctly.
