04
WARNINGWARNING
Sealed electrical components shall be replaced.
Intrinsically safe components must be replaced.
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.
Under no circumstances shall potential sources
of ignition be used while searching for or
detecting of refrigerant leaks. A halide torch (or
any other detector using a naked flame) shall not
be used.
Electronic leak detectors may be used to detect
refrigerant leaks but, in the case of flammable
refrigerants, the sensitivity may not be adequate,
or may need re-calibration. (Detection equipment
shall be calibrated in a refrigerant-free area.)
Ensure that the detector is not a potential source
of ignition and is suitable for the refrigerant used.
Leak detection equipment shall be set at a
percentage of the LFL of the refrigerant and shall
be calibrated for the refrigerant employed, and
the appropriate percentage of gas (25 %
maximum) is confirmed.
If a leak is suspected, all naked flames shall be
removed/extinguished.
If a leakage of refrigerant which requires brazing
is found, all of the refrigerant shall be recovered
from the system, or isolated(by means of shut off
valves) in a part of the system remote from the
leak.
Refrigerant pipe or components are installed in a
position where they are unlikely to be exposed to
any substances which may corrode refrigerant
containing components, unless the components
are constructed of materials that are inherently
resistant to corrosion or are suitably protected
against corrosion.
Repair and maintenance of electrical components
shall include initial safety checks and component
inspection procedures. If a fault exists that could
compromise safety, then no electrical supply
shall be connected to the circuit until the fault
has been dealt with satisfactorily.
If the fault cannot be corrected immediately but it
is necessary to continue operation, an adequate
temporary solution shall be used. This shall be
reported to the owner of the equipment so that
all parties are advised. Initial safety checks shall
include:
– That capacitors are discharged: this shall be
done in a safe manner to avoid the possibility of
sparking;
– That no live electrical components and wiring
are exposed while charging, recovering or
purging the system;
– That there is continuity of grounding.
Leak detection fluids are also suitable for use
with most refrigerants but the use of detergents
containing chlorine shall be avoided as the
chlorine may react with the refrigerant and
corrode the copper pipe-work.
NOTE：Examples of leak detection fluids are
-bubble method,
-A2L Compliant Leak Detector.
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 be followed, since
flammability is a consideration. The following
procedure shall be adhered to:
- safely remove refrigerant following local and
national regulations
- evacuate
-purge the circuit with inert gas
- evacuate
- continuously flush or purge with inert gas when
using flame to open circuit, and
- open the circuit
The refrigerant charge shall be recovered into
the correct recovery cylinders if venting is not
allowed by local and national codes. For
appliances containing flammable refrigerants,
the system shall be purged with oxygen-free
nitrogen to render the appliance safe for
flammable refrigerants. This process might need
to be repeated several times. Compressed air or
oxygen shall not be used for purging refrigerant
systems.
For appliances containing flammable
refrigerants, refrigerant purging shall be
accomplished by breaking the vacuum in the
system with oxygen-free nitrogen and continuing
to fill it until the desired working pressure is
reached. Afterwards, the system should be
vented to the atmosphere and then pulled 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.
The outlet for the vacuum pump shall not be
close to any potential ignition sources, and
ventilation shall be available.
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
they contain.
When use a refrigerant tank with siphon to add
refrigerant, the refrigerant tank should be placed
upright. When use a refrigerant tank without
siphon to add refrigerant, the refrigerant tank
should be placed upside down. Ensure that the
refrigeration system is grounded prior to charging
the system with refrigerant.
Label the system when charging is complete (if it
is not already labeled).
Take extreme care not to overfill the refrigeration
system.
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