Panasonic S-160PE1R5B Technical Data & Service Manual page 62

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6. Detection of fl ammable refrigerants
• Under no circumstances shall potential sources of ignition be used in the searching for or detection
of refrigerant leaks.
• A halide torch (or any other detector using a naked fl ame) shall not be used.
7. Leak detection methods
• Electronic leak detectors may be used to detect refrigerant leaks but, in the case of fl ammable
refrigerants, 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 lower flammable limit (LFL) of the refrigerant
and shall be calibrated to the refrigerant employed, and the appropriate percentage of gas (25 % maximum)
is confirmed.
• Leak detection fl uids are suitable for use with most refrigerants but 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.
For appliances containing fl ammable refrigerants, Oxygen free nitrogen (OFN) shall then be purged through
the system both before and during the brazing process.
8. 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:
• 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 "fl ushed" 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 purging refrigerant systems.
• Flushing shall be achieved by breaking the vacuum in the system with Oxygen free nitrogen (OFN)
and continuing to fi ll until the working pressure is achieved, then venting to atmosphere, and fi nally
pulling down to a vacuum.
• This process shall be repeated until no refrigerant is within the system.
• When the fi nal Oxygen free nitrogen (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 ignition sources and that ventilation
is available.
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