Toshiba MMU-UP0151SH-E Manual De Instalación página 12

15.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 purging refrigerant
systems.
• 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 that ventilation available.
16.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 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.
21-EN
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• Prior to recharging the system, it shall be pressure-tested with the
appropriate purging gas.
• 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.
17.Decommissioning
• Before carrying out this procedure, it is essential that the technician
is completely familiar with the equipment and all its details.
• 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 to reuse 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 on the
equipment are closed off.
k ) Recovered refrigerant shall not be charged into another
refrigeration system unless it has been cleaned and checked.
22-EN