Blaupunkt Moby Blue S 0709E - Refrigerant Handling and System Procedures

MBS0709E, MBS12E
www.blaupunkt.com
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5. Detection of 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 ame)
shall not be used.
6. Leak detection methods
The following leak detection methods are deemed acceptable for systems containing
ammable refrigerants. Electronic leak detectors shall be used to detect ammable 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 conrmed. Leak detection 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 ames
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 o 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 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 “ushed” 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 ll until the
working pressure is achieved, then venting to atmosphere, and nally pulling down to
a vacuum. This process shall be repeated until no refrigerant is within the system. When
the nal 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.