
or explosion, including cigarette smoking, must be kept
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may be released to the surrounding space. The area around
the equipment shall be checked before beginning the work
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Smoking” signs shall be displayed.
The area must be adequately ventilated before beginning the
work, and a degree of ventilation must be ensured while the
work is being carried out. Ventilation should safely disperse
any released refrigerant and preferably expel it externally
into the atmosphere.
Repair and maintenance of electrical components shall
include initial safety checks and component inspection
procedures. If a fault compromises safety, then the circuit
shall not be connected to the power supply until the fault has
been solved satisfactorily. If the fault cannot be addressed
immediately, but it is necessary to resume operation, an
adequate temporary solution shall be applied. This shall be
reported to the owner of the equipment so all parties are
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&DSDFLWRUGLVFKDUJH7KLVVKDOOEHGRQHLQDVDIHPDQQHU
to avoid sparks
Exposure of live electrical components and wiring while
the system is being charged, recovered or purged
Continuity of earth bonding
During repair works, all the power supply connections must
be disconnected from the equipment before removing any
part such as a sealed cover. If it is absolutely necessary to
keep the power supply of the equipment during servicing,
then a permanently operating form of leak detection shall
be located at the most critical point to warn of a potentially
hazardous situation.
Particular attention shall be paid not to alter the casing when
working on electrical components, in such a way that the
level of protection is affected. This includes the damage
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connections, etc. The unit shall be mounted securely, and
the seals or sealing materials must not have been degraded
such that they no longer serve the purpose of preventing the
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NOTE
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Do not apply any permanent inductive or capacitive load
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exceed the permissible voltage and current permitted for the
equipment in use.
Intrinsically safe components do not have to be isolated
before working on them. They are the only type which can
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atmosphere. The test apparatus shall be at the correct
rating.
Check that wiring is not subject to wear, corrosion, excessive
pressure, vibration, sharp edges or any other cause of
damage. The check shall also take into account the effect
of ageing or continual vibration from sources such as
compressors of fans.
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refrigerants, but the sensitivity may not be adequate, or may
need recalibration. (Detection equipment shall be calibrated
in a refrigerant-free area)
Under no circumstance shall potential sources of ignition be
used for searching or detecting refrigerant leaks. A halide
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be used.
It must be ensured that the detector is not a potential source
of ignition while being suitable for the refrigerant used. Leak
detection equipment shall be set to a percentage of the LFL
(0.307 kg/m3) of the refrigerant and shall be calibrated to the
refrigerant employed and the appropriate percentage of gas
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chlorine shall be avoided as the chlorine may react with the
refrigerant and corrode the copper pipework.
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extinguished. If a leakage of refrigerant is found which
requires brazing, the refrigerant shall be either entirely
recovered from the system, or isolated in a part of the
system remote from the leak by means of shut off valves.
Oxygen-free nitrogen (OFN) shall then be purged through
the system, both before and during the brazing process.
The procedure below shall be followed when breaking
into the refrigerant circuit to make repairs or for any other
SXUSRVH
remove refrigerant;
purge the circuit with inert gas;
evacuate;
purge again with inert gas;
open the circuit by cutting or brazing.
The refrigerant charge shall be recovered into the correct
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Oxygen free nitrogen (OFN) to render the unit safe.
This process may need to be repeated several times.
Compressed air or oxygen shall not be used for this task.
Flushing shall be achieved by breaking the vacuum in the
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pressure is achieved, then venting to atmosphere, and
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repeated until no refrigerant is within the system. When the
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to atmospheric pressure to enable work to take place. This
operation is absolutely vital if brazing operations on the
pipework are to take place.
Ensure that the outlet for the vacuum pump is not close to
any ignition sources and there is ventilation available.
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
IMPORTANT NOTICE
PMML0515 rev.0 - 03/20194