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SAFETY INSTRUCTIONS
- If a leakage of refrigerant is found which requires brazing, all of the refrigerant shall be
recovered from the system, or isolated (by means of shut off valves) in a part of the system
remote from the leak.
11. 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 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 purged with OFN to render the appliance safe for flammable refrigerants. This
process may need to be repeated several times. Compressed air or oxygen shall not be
used for this task. Purging shall be achieved by breaking 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 charge is used,
the system shall be vented down to atmospheric pressure to enable work. 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 potential ignition sources and there is the
vacuum in the system with OFN and continuing ventilation available.
12. 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 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).
- Extreme care shall be taken not to overfill the refrigerating 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.
13. 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 recovered refrigerant. It is essential
that electrical power is available before the task is commenced.
a. Become familiar with the equipment and its operation.
b. Isolate system electrically.
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