Publicidad
Idiomas disponibles
Idiomas disponibles
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 pipe-work are to take
place.
Ensure that the outlet for the vacuum pump is not close to any ignition sources and
there 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. 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 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
18
Publicidad
