11
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.
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 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.
17. 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
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.
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.
19. Recovery
When removing refrigerant from a system, either for
servicing or decommissioning, it 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 is available. All cylinders to be
used are designated for the recovered refrigerant and
labelled for that refrigerant (i.e. special cylinders for
the recovery of refrigerant). Cylinders shall be complete
with pressure relief valve and associated shut-off valves
in good working order. Empty recovery cylinders are
evacuated and, if possible, cooled before recovery
occurs. The recovery equipment shall be in good working
order with a set of instructions concerning the equipment
that is at hand and shall be suitable for the recovery of
flammable refrigerants. In addition, a set of calibrated
weighing scales shall be available and in good working
order. Hoses shall be complete with leak-free disconnect
couplings and in good condition. Before using the
recovery machine, check that it is in satisfactory working
order, has been properly maintained and that any
associated electrical components are sealed to prevent
ignition in the event of a refrigerant release. Consult
manufacturer if in doubt. The recovered refrigerant shall
be returned to the refrigerant supplier in the correct
recovery cylinder, and the relevant Waste Transfer Note
arranged. Do not mix refrigerants in recovery units and
especially not in cylinders. If compressors or compressor
oils are to be removed, ensure that they have been
evacuated to an acceptable level to make certain
that flammable refrigerant does not remain within
the lubricant. The evacuation process shall be carried
out prior to returning the compressor to the suppliers.
Only electric heating to the compressor body shall be
employed to accelerate this process. When oil is drained
from a system, it shall be carried out safely
