Nobu GR-10L User Manual page 12

SAFETY PRECAUTIONS
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.
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
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.
13. 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
equipment. Hoses or lines shall be as short as possible to minimize the amount of refrigerant
contained in them.
-Cylinders shall be kept upright.
-Ensure that the refrigeration system is earthed prior to charging the system with refrigerant.
-label the system when charging is complete (if not already)
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