Nordic Home AC-511 Manual Del Usuario página 37

• Discharge of capacitors: this must be done in a safe manner to prevent sparking;
• Ensuring that there are no live electrical components or wiring exposed while charging, recovering or purging the
system;
• That there is continuity of earth bonding.
7. Repairs to sealed components
1) When repairing sealed components, all power supplies must be disconnected from the equipment being worked
upon before any removal of sealed covers, etc. If it is absolutely necessary to maintain a power supply to equip-
ment during servicing, a permanently operating form of leak detection must be located at the most critical point to
provide a prior warning of any potentially hazardous situation.
2) Particular attention must be paid to the following to ensure that working on electrical components does not result
in alteration of the casing is in such a way that the level of protection is affected.
This must include damage to cables, excessive number of connections, terminals not made to original specification,
damage to seals, incorrect fitting of cable glands, etc.
Ensure that apparatus is mounted securely.
Ensure that seals or sealing materials have not degraded such that they no longer prevent the ingress of flammable
atmospheres. Replacement parts must 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. Intrinsi-
cally safe components do not have to be isolated prior to working on them.
8. Repairing intrinsically safe components
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 must be at the correct rating.
Replace components only with parts specified by the manufacturer. Other parts may result in the ignition of leaked
refrigerant in the atmosphere.
9. Cabling
Check that cabling will not be subject to wear, corrosion, excessive pressure, vibration, sharp edges, or any other
adverse environmental effects. The check must also take into account the effects of aging or constant vibration
from sources such as compressors or fans.
10. Detection of flammable refrigerants
Under no circumstances should potential sources of ignition be used when searching for or detecting refrigerant
leaks. Halide torches (or any other detector use naked flames) must not be used.
11. Leak detection methods
The following leak detection methods are deemed acceptable for systems containing flammable refrigerants.
Electronic leak detectors may be used to detect flammable refrigerants, but the sensitivity may not be adequate,
or may need re-calibration. (Detection equipment must be calibrated in a refrigerant-free area.) Ensure that the de-
tector 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 must be calibrated to the refrigerant used and the appropriate
percentage of gas (25 % maximum) must be confirmed.
Leak detection fluids are suitable for use with most refrigerants, but the use of detergents containing chlorine must
be avoided as the chlorine may react with the refrigerant and corrode the copper pipework.
If a leak is suspected, all naked flames must be removed / extinguished.
If a leakage of refrigerant is found which requires brazing, all of the refrigerant must be recovered from the system
or isolated (by means of shut-off valves) in a part of the system not affected by the leak. Oxygen- free-nitrogen
(OFN) must then be passed through the system both before and during the brazing process.
12. Removal and evacuation
Conventional procedures must be used when accessing the refrigerant circuit for repairs or any other purpose.
However, it is important that best practice is followed since flammability must be considered. The following procedu-
re must be adhered to:
• Remove the refrigerant;
• Purge the circuit with inert gas;
• Evacuate the circuit;
• Purge again with inert gas;
• Open the circuit by cutting or brazing.
The refrigerant charge must be recovered into the correct recovery cylinders. The system must be flushed with
OFN to render the unit safe. This process may need to be repeated several times. Compressed air or oxygen must
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