INVENTOR CB-WUI-20L Manual De Usuario página 13

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.
8. 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 flammable atmosphere. The test apparatus shall be at the correct rating. Replace
components only with parts specified by the manufacturer. Other parts may result in the ignition
of refrigerant in the atmosphere from a leak.
9. 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 leaks. A halide torch (or any other detector using a naked flame)
shall not be used
10. 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.
11. 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 refrigerants, but the sensitivity
may not be adequate, or may need re-calibrated.(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 confirmed .
Leak detection fluids are suitable for use with most refrigerants but the use of detergents
containing chlorine shall be avoided as the 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 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 both before
and during the brazing process.
Oxygen free nitrogen (OFN) shall then be purged through the system both before and during
the brazing process.
12. 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 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 processing 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
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EN