INVENTOR U5MRSL322-18 Installationshandbuch Seite 31

12. 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.
13. 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.
14. 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 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. 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 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 or extinguished. If a leakage of refrigernat
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 . Oxygen free
nitrogen(OFN) shall then be purged through the system both before and during the brazing process.
15. Removal and evacuation
When breaking into the refrigerant circuit to make repairs of for any other purpose
conventional 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 closed to any ignition sources and there
is ventilation available.
16. Charging procedures
In addition to conventional charging procedures, the following requirements shall be followed:
Ensure that contamination of different refrigerants does not occur when using charging
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