Sinclair SDV 6 Service Manual page 8

Since flammability 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 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 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 operations 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 ventilation available. 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. Prior to recharging the system it shall be
pressure tested with OFN.
DD.12 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.
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.
j) When the cylinders have been filled correctly and the process completed, make sure that the cylinders and the
equipment are removed from site promptly and all isolation valves on the equipment are closed off.
k) Recovered refrigerant shall not be charged into another refrigeration system unless it has been clean ed and checked.
Equipment shall be labelled stating that it has been de-commissioned and emptied of refrigerant. The label shall be
dated and signed. Ensure that there are labels on the equipment stating the equipment contains flammable refrigerant.
When removing refrigerant from a system, either for servicing or decommissioning, it is recommended good practice
that all refrigerants are removed safely.
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