Tesla TT27TP21-0932IAWT, User Manual

Page: 16 / 348

16
ENG
- 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.
23. 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 onthe equipment are closed off.
k. Recovered refrigerant shall not be charged into another refrigeration system unless it has been cleaned and
checked.
24. Labelling
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.
25. 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 are available. All
cylinders to be used are designated for the recovered refrigerant and labelled for that refrigerant (i.e. special
cylinders for the recovery of refrigerant). Cylinders shall be complete with pressure-relief valve and associated
shut-off valves in good working order. Empty recovery cylinders are evacuated and, if possible, cooled before
recovery occurs.
The recovery equipment shall be in good working order with a set of instructions concerning the equipment
that is at hand and shall be suitable for the recovery of all appropriate refrigerants including, when applicable,
flammable refrigerants. In addition, a set of calibrated weighing scales shall be available and in good working
order. Hoses shall be complete with leak-free disconnect couplings and in good condition. Before using the
recovery machine, check that it is in satisfactory working order, has been properly maintained and that any
associated electrical components are sealed to prevent ignition in the event of a refrigerant release. Consult
manufacturer if in doubt.
The recovered refrigerant shall be returned to the refrigerant supplier in the correct recover cylinder, and the
relevant waste transfer note arranged. Do not mix refrigerants in recovery units and especially not in cylinders.
If compressors or compressor oils are to be removed, ensure that they have been evacuated to an acceptable
level to make certain that flammable refrigerant does not remain within the lubricant. The evacuation process
shall be carried out prior to returning the compressor to the suppliers. Only electric heating to the compressor
body shall be employed to accelerate this process. When oil is drained from a system, it shall be carried out
safely.