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MAINTENANCE AND SERVICE
18
Caution! Flammable Refrigerant.
Refrigerant Removal and ejection
When breaking into the refrigerant circuit to make repairs – or for any other purpose – conven-
tional procedures shall be used. However, it is important that best practice is followed since flam-
mability 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 braking 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 absolutely vital if brazing operation 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 ven-
tilation available.
Disposal method and precaution
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 refrigerant are recov-
ered safety, 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.
a) Become familiar with the equipment and its operation
b) Isolate system electrically
c) Before attempting the procedure ensure that;
• Mechanical handling equipment is available. If required. For handling refrigerant cylinders;
• All personal protective equipment is available and being used correctly;
• The recovery process is supervised at all times by a competent person;
• Recovery equipment and cylinders conform to the appropriate standards;
d) Pump down refrigerant system, if possible.
e) If a vacuum is not possible, make a manifold so that refrigerant can be removed from various
parts of the system.
f) Make sure that cylinder is situated on the scales before recovery takes place.
g) Start the recovery machine and operate in accordance with manufacturer's instructions.
h) Do not overfill cylinders. (No more than 80 % volume liquid charge).
i) Do not exceed the maximum working pressure of the cylinder, even temporarily.
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