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12 13
12. Removal and Evacuation
When breaking into the refrigerant circuit to make repairs or for any other purpose, conventional
procedures shall be used. Considering flammability, follow best practices. Opening of the refrigeration
systems shall not be done by brazing. Adherence to the following procedures is a must:
a) Removing the refrigerant;
b) Purging the circuit with inert gas;
c) Evacuation;
d) Purging again with inert gas;
e) Opening 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 the atmosphere, and finally pulling down to a vacuum. This
process shall be repeated until no refrigerant is inside 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 pipework are to take place.
Ensure that the outlet for the vacuum pump is not near any ignition sources and that ventilation
is available.
13. 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 the charging equipment. Hoses or lines
shall be as short as possible to minimize the amount of refrigerant contained in them.
Cylinders shall be kept upright.
Ensure that the refrigeration system is earthed before charging the system with the refrigerant. Label the
system when the charging is complete (in case it has not been labeled yet).
Extreme care shall be taken to avoid overfilling the refrigeration system.
Prior to recharging the system, the pressure test with OFN must first be conducted. The system leak test
shall be performed upon completion of charging, but should be done prior to commissioning.
A follow up leak test shall be carried out before leaving the site.
14. Decommissioning
Before carrying out this procedure, it is essential that the technician is completely familiar with the
equipment and all necessary details. It is good practice that all refrigerants be recovered safely.
Prior to carrying out this task, an oil and refrigerant sample shall be taken in case analysis is required
before reusing the reclaimed refrigerant. It is essential that electrical power is available before
this task commences.
a) Become familiar with the equipment and its operation.
b) Isolate the system electrically.
c) Before attempting the procedure, ensure that:
Mechanical handling equipment is available, if required, for handling refrigerant cylinders;
Allpersonal protective equipment is available and being used correctly;
The recovery process is always supervised by a competent person and recovery equipment
and cylinders conform to the required standards.
d) Pump down the refrigerant system, if possible.
e) If a vacuum is not possible, make a manifold so that refrigerants can be removed from
various parts of the system.
f) Make sure that the cylinder is situated on the scales before recovery takes place.
g) Start the recovery machine and operate in accordance with the manufacturer's instructions.
h) Do not overfill the 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 is completed, make sure that the
cylinders and the equipment are removed from the 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
cleaned and checked.
15. Labeling
The unit shall be labeled stating that it has been decommissioned and emptied of the refrigerant.
The label shall be dated and signed. Ensure that there are labels on the unit stating that it contains
flammable refrigerants.
16. Recovery
When removing the refrigerant from a system, either for servicing or decommissioning, it is recommended
that all refrigerants are removed safely.
When transferring the refrigerant into the cylinders, ensure that only appropriate refrigerant recovery
cylinders are used. Ensure that the correct number of cylinders for holding the total system charge
is available. All cylinders to be used are designated for the recovered refrigerant and labeled for that
refrigerant (i.e., special cylinders refrigerant recovery). Cylinders shall be complete with pressure relief
valves and associated shut-off valves in good working order. Empty recovery cylinders should be evacuated
and, if possible, cooled before the 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 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 if a refrigerant is released. Consult Customer Service when in
doubt.
The recovered refrigerant shall be returned to the refrigerant supplier in the correct recovery cylinder, and
the relevant Waste Transfer Note arranged. Do not mix refrigerants in recovery units and especially not
in cylinders. If the compressors or the compressor oils are to be removed, ensure that they have been
evacuated to an acceptable level so that the 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 the system, it shall be carried out safely.
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