Panasonic S-3650PU3E Technical Data & Service Manual page 155

3. Repairs to sealed components
• 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.
• If it is absolutely necessary to have an electrical supply to 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 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 specifi cation, damage to seals, incorrect fi tting 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 fl ammable atmospheres.
• Replacement parts shall be in accordance with the
manufacturer's specifi cations.
4. Repair to 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 fl ammable atmosphere.
• The test apparatus shall be at the correct rating.
• Replace components only with parts specifi ed by the manufacturer. Unspecifi ed parts by manufacturer may result
ignition of refrigerant in the atmosphere from a leak.
5. Cabling
• 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.
6. Detection of fl ammable refrigerants
• Under no circumstances shall potential sources of ignition be used in the searching or detection of refrigerant leaks.
• A halide torch (or any other detector using a naked fl ame) shall not be used.
• The following leak detection methods are deemed acceptable for all refrigerant systems.
- No leaks shall be detected when using detection equipment with a sensitivity of 5 grams per year of refrigerant
or better under a pressure of at least 0,25 times the maximum allowable pressure (>1.04MPa, max 4.15MPa) for
example, a universal sniffer.
- Electronic leak detectors may be used to detect fl ammable refrigerants, but 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 to the
refrigerant employed and the appropriate percentage of gas (25 % maximum) is confi rmed.
- Leak detection fl uids are also suitable for use with most refrigerants, for example, bubble method and fl uorescent
method agents. The use of detergents containing chlorine shall be avoided as the chlorine may react with the
refrigerant and corrode the copper pipe-work.
- If a leak is suspected, all naked fl ames shall be removed/extinguished.
- If a leakage of refrigerant is found which requires brazing, 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. The precautions in #7 must
be followed to remove the refrigerant.
7. Removal and evacuation
• 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 fl ammability is a consideration.
The following procedure shall be adhered to:
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.
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