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6. 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 ammability is a consideration.
The following procedure shall be adhered to:
• Remove refrigerant;
• Purge the circuit with inert gas (optional for
A2L);
• Evacuate (optional for A2L);
• Purge with inert gas (optional for A2L);
• Open the circuit by cutting or brazing.
The refrigerant charge shall be recovered into
the correct recovery cylinders. For appliances
containing ammable refrigerants other than
A2L refrigerants, the system shall be purged with
oxygen-free nitrogen to render the appliance
safe for ammable refrigerants. This process may
need to be repeated several times. Compressed
air or oxygen shall not be used for purging
refrigerant systems.
For appliances containing ammable
refrigerants, other than A2L refrigerants,
refrigerants purging shall be achieved by
breaking the vacuum in the system with
oxygen-free nitrogen and continuing to ll until
the working pressure is achieved, then venting
to atmosphere, and nally pulling down to a
vacuum. This process shall be repeated until no
refrigerant is within the system. When the nal
oxygen-free nitrogen 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 potential ignition sources and
there is ventilation available.
7. 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 in an appropriate
position according to the instructions.
– Ensure that the refrigerating 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 overll the
refrigerating 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.
8. 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 recovered
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.
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