Removal And Evacuation; Charging Procedures - Black & Decker BXAC9000E Instructions Manual

tinguished. If a leakage of refrigerant is found
which requires brazing, all of the refrigerant
shall be recovered from the system, or isolat-
ed (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.

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 for the vacuum pump is
not close to any ignition sources and there is
ventilation available.

CHARGING PROCEDURES

- In addition to conventional charging proce-
dures, the following requirements shall be
followed.
- Ensure that contamination of different refrig-
erants 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.
(Original instructions)
- 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 essen-
tial that the technician is completely familiar
with the equipment and all its detail. It is rec-
ommended 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
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 pressu-
re 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
ENGLISH
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