Panasonic U-4LZ2E5 Manual Del Usuario página 8

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.
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