Whirlpool 20K Manual Del Usuario página 43

adverse environmental effects.The
check shall also take into account the
effects of aging or continual vibration
from sources such as compressors or
fans.
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-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 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 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
remote from the leak.
- 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
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 charge is used, the system
shall be vented down to atmospheric
pressure to enable work. 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 the vacuum in
the system with OFN and continuing
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.
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