|Warnings (for using R290/R32 refrigerant only)
in order to make any repairs or for any other
purposes, conventional procedures should
be applied. However, it is strongly suggested
that safe practice is followed, and flammability
should be taken under consideration.
The following procedure should be followed as
to:
Remove refrigerant,
Purge the circuit with inert gas,
Evacuate,
Purge again with inert gas,
Open the circuit by performing a cut or brazing.
The refrigerant charge should be recovered
into the assigned and correct recovery
cylinders, The system must be flushed with OFN
to render the unit safe, This process may be
repeated several times. The use of Compressed
air oxygen may not be used for this act.
Flushing may be achieved by breaking the
vacuum in the system with OFN and continuing
to fill until the working pressure has been
achieved, then venting to atmosphere, and
finally pulling down to a vacuum. This process
should be repeated until no refrigerant is left
within the system. When the final OFN charge
is used, the system shall be vented down to
atmospheric pressure to enable any work to be
performed. This operation is absolutely crucial
if brazing operations on the pipe- work are
intended to take place.
Ensure that the outlet for the vacuum pump is
not close to any ignition sources and there is
plenty of ventilation available.
13. Charging procedures
In addition to conventional charging
procedures, the following requirements should
be followed.
Ensure that the contamination of different
refrigerants does not occur when using
charging equipment. Hoses or lines shall be as
short as possible to minimise t he amount of
refrigerant contained in them.
Cylinders shall be kept in an upright position.
Ensure that the refrigeration system is
earthed prior to charging the system with any
refrigerant.
Label the system when charging is complete (if
not labeled already).
Extreme care mustl be taken not to overfill
the refrigeration system. Prior to recharging
the system, it must be pressure tested with
8
OFN. The system must also be leak tested
on completion of charging but prior to
commissioning. A follow up leak test should be
carried out prior to leaving the site.
14. Decommissioning
Before carrying out this procedure, it is
essential that the technician is completely
familiar with the equipment and all its details.
It is considered as good practice that all
refrigerants are recovered safely. Prior to the
task being carried out, an oil and refrigerant
sample shall be taken, in the event that 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) Electrically isolate the system.
c) Before attempting this procedure please
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.
15. Labelling
Equipment must be labelled stating that it
has been de- commissioned and emptied of
EN