Qlima P 652 Instrucciones De Uso página 56

lf a leakage of refrigerant is found which requires brazing, all of the refrigerant shall be
recovered from the system, or isolated (by means of shut off valves} in a part of the system
remote from the leak. Oxygen free nitrogen (OFN) shall then be purged through the
system both before and during the brazing process.
7 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: 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 pipework are to take place. Ensure that the outlet tor the vacuum pump
is not close to any ignition sources and !here is ventilation available.
8 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.
9 DECOMMISSIONING
Before carrying out this procedure, it is essential that the technician is completely
familiar with the equipment and all its detail. lt 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. lt is essential that 4 GB electrical power is available before the task is
commenced.
a) Become familiar with the equipment and its operation.
b) lsolate system electrically.
c) Before attempting the procedure ensure that: mechanical handling equipment is
available, if required, for handling refrigerant cylinders;
d) All personal protective equipment is available and being used correctly; the recovery
process is supervised at all times by a competent person;
e) recovery equipment and cylinders conform to the appropriate standards.
f) Pump down refrigerant system, if possible.
g) lf a vacuum is not possible, make a manifold so that refrigerant can be removed from
various parts of the system.
h) Make sure that cylinder is situated on the scales before recovery takes place.
i) Start the recovery machine and operate in accordance with manufacturer's instructions.
j) Do not overfill cylinders. (No more than 80 % volume liquid charge).
k) Do not exceed the maximum working pressure of the cylinder, even temporarily.
l) 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.
m) Recovered refrigerant shall not be charged into another refrigeration system unless it
has been cleaned and checked.
10 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.
11 RECOVERY
When removing refrigerant from a system, either for servicing or decommissioning, il 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
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