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Idiomas disponibles
Idiomas disponibles
• 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:
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Safely remove refrigerant following local and national regulations;
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purge the circuit with inert gas;
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evacuate;
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purge again with inert gas;
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open the circuit by cutting or brazing.
The refrigerant charge shall be recovered into the correct recovery cylinders if venting is not allowed by local and national codes. For
appliances containing flammable refrigerants, the system shall be purged with oxygen-free nitrogen to render the appliance safe for
flammable refrigerants. This process might need to be repeated several times. Compressed air or oxygen shall not be used for purging
refrigerant systems.
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.
• Labelling
This unit shall be labelled 'de-commissioned and emptied of refrigerant'. This label shall be dated and signed. Ensure that there are
labels on the equipment stating the equipment contains flammable refrigerant.
• 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 minimise the amount of refrigerant contained in them.
– Cylinders shall be kept upright.
– Ensure that the refrigeration 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 refrigeration 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.
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:
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mechanical handling equipment is available, if required, for handling refrigerant cylinders;
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all personal protective equipment is available and being used correctly;
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the recovery process is supervised at all times by a competent person;
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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 cleaned and checked.
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 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 recovery 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.
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