Blaupunkt Moby Blue S 0709E Bedienungsanleitung Seite 21

MBS0709E, MBS12E
5. Detection of flammable 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 flame)
shall not be used.
6. Leak detection methods
The following leak detection methods are deemed acceptable for systems containing
flammable refrigerants. Electronic leak detectors shall be used to detect flammable re-
frigerants, but the sensitivity may not be adequate, or may need re-calibration. (Detec-
tion 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 calibrat-
ed to the refrigerant employed and the appropriate percentage of gas (25 % maximum)
is confirmed. Leak detection fluids 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 flames
shall be removed/ extinguished. If a leakage of refrigerant is found which requires braz-
ing, 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. Oxygen free nitrogen (OFN)
shall then be purged through the system both before and during the brazing process.
7. Removal and evacuation
When breaking into the refrigerant circuit to make repairs – or for any other purpose – con-
ventional 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 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 ignition sources and there is ventilation available.
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