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permissible voltage and current permitted for
the equipment in use.
♦
Intrinsically safe components are the only
types that can be worked on while live in the
presence of a flammable atmosphere. The test
apparatus shall be at the correct rating.
♦
Replace components only with parts specified
by the manufacturer. Other parts may result
in the ignition of refrigerant in the atmosphere
from a leak.
12. Cabling
♦
Check that cabling will not be subject to wear,
corrosion, excessive pressure, vibration, sharp
edges or any other adverse environmental
effects. The check shall also take into account
the effects of aging or continual vibration from
sources such as compressors or fans.
13. Detection of flammable refrigerants
♦
Under no circumstances shall potential sources
of ignition be used in the searching for or
detection of refrigerant leaks. A halide torch (or
any other detector using a naked flame) shall
not be used.
♦
Removal and evacuation
♦
When breaking into the refrigerant circuit
to make repairs – or for any other purpose
– conventional procedures shall be used.
However, for flammable refrigerants 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 with inert gas;
♦
Open the circuit by cutting or brazing.
♦
The refrigerant charge shall be recovered
into the correct recovery cylinders.
For appliances containing flammable
refrigerants the system shall be purged
with oxygen-free nitrogen to render the
appliance safe for flammable refrigerants.
This process may need to be repeated
several times.
♦
Compressed air or oxygen shall not be used for
purging refrigerant systems.
(Original instructions)
♦
For appliances containing flammable
refrigerants, refrigerants purging shall be
achieved by breaking the vacuum in the system
with oxygen-free nitrogen 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 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
that ventilation is available.
♦
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 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 overfill the
refrigerating system.
♦
Prior to recharging the system, it shall
be pressure-tested with the appropriate
purging gas. 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.
14. 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.
ENGLISH
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