viii
(3) The area shall be checked with an appropriate refrigerant detector prior to and
during work, to ensure the technician is aware of potentially toxic or flammable
atmospheres. Ensure that the leak detection equipment being used is suitable
for use with all applicable refrigerants, i.e. non-sparking, adequately sealed or
intrinsically safe.
(4) If any hot work is to be conducted on the refrigerating equipment or any
associated parts, appropriate fire extinguishing equipment shall be available to
hand. Have a dry powder or CO
2
fire extinguisher adjacent to the charging area.
(5) No person carrying out work in relation to a refrigerating system which involves
exposing any pipe work shall use any sources of ignition in such a manner
that it may lead to the risk of fire or explosion. All possible ignition sources,
including cigarette smoking, should be kept sufficiently far away from the site
of installation, repairing, removing and disposal, during which refrigerant can
possibly be released to the surrounding space. Prior to work taking place, the
area around the equipment is to be surveyed to make sure that there are no
flammable hazards or ignition risks. “No Smoking” signs shall be displayed.
(6) Ensure that the area is in the open or that it is adequately ventilated before
breaking into the system or conducting any hot work. A degree of ventilation shall
continue during the period that the work is carried out. The ventilation should
safely disperse any released refrigerant and preferably expel it externally into the
atmosphere.
(7) Where electrical components are being changed, they shall be fit for the purpose
and to the correct specification. At all times the manufacturer’s maintenance
and service guidelines shall be followed. If in doubt, consult the manufacturer’s
technical department for assistance.
•
The actual refrigerant charge is in accordance with the room size within which
the refrigerant containing parts are installed.
•
The ventilation machinery and outlets are operating adequately and are not
obstructed.
•
Marking to the equipment continues to be visible and legible. Markings and
signs that are illegible shall be corrected.
•
Refrigerating pipe or components are installed in a position where they are
unlikely to be exposed to any substance which may corrode refrigerant
containing components, unless the components are constructed of materials
which are inherently resistant to being corroded or are suitably protected
against being so corroded.
(8) Repair and maintenance to 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 it is satisfactorily dealt with. 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 all parties are
advised.
Initial safety checks shall include:
•
That capacitors are discharged. This shall be done in a safe manner to avoid
possibility of sparking.
•
That no live electrical components and wiring are exposed while charging,
recovering or purging the system.
•
That there is continuity of earth bonding.
• During repairs to sealed components, all electrical supplies shall be disconnected
from the equipment being worked upon prior to any removal of sealed covers, etc.
00_330344_2WAY_Eng.indb 7 2020/12/21 11:26:34
• Particular attention shall be paid to the following to ensure that by working on
electrical components, the casing is not altered in such a way that the level of
protection is affected. This shall include damage to cables, excessive number of
connections, terminals not made to original specification, damage to seals,
incorrect fitting of glands, etc.
• Ensure that apparatus is mounted securely.
• Ensure that seals or sealing materials have not degraded such that they no longer
serve the purpose of preventing the ingress of flammable atmospheres.
• Replacement parts shall be in accordance with the manufacturer’s specifications.
NOTE:
The use of silicon sealant may inhibit the effectiveness of some types of leak
detection equipment. Intrinsically safe components do not have to be isolated prior
to working on them.
• Do not apply any permanent inductive or capacitance loads to the circuit without
ensuring that this will not exceed the 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. Unspecified parts
by manufacturer may result ignition of refrigerant in the atmosphere from a leak.
REMOVAL AND EVACUATION
CAUTION
• 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 flammability is a
consideration.
The following procedure shall be adhered to:
•
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 recovery cylinders.
•
The system shall be “flushed” with 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 system with OFN 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 OFN 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.
00_330344_2WAY_Eng.indb 8 2020/12/21 11:26:34
SM830289-01_欧州向け R32 mini VRF 8,10HP SM&TRSM.indb 8SM830289-01_欧州向け R32 mini VRF 8,10HP SM&TRSM.indb 8 2021/05/07 10:08:282021/05/07 10:08:28
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