Kunft KAC4254 Manual De Instrucciones página 10

If a leak is suspected, all naked flames shall be removed or
extinguished. If 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.
15. Removal and evacuation
When accessing the refrigerant circuit to make repairs 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 it 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 in 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 closed to any
ignition sources and there is ventilation available.
16. Charging procedures
In addition to conventional charging procedures, the following requi-
rements 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 minimize 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.
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portable air conditioner
17. Decommissioning
Before carrying out this procedure, it is essential that the technician
be 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 the cylinders (no more than 80 % of the 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 com-
pleted, make sure 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 refrigera-
tion system unless it has been cleaned and checked.
18. 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.
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EN
KAC4254