5
• 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 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.
• Before carrying out this
procedure, it is essential that
the technician is completely
familiar with the equipment and
all its detail. It is recommended
good practice that all
refrigerants are recovered
safely. Prior to the task being
carried out, an oil and
refrigerant sample shall be
taken in case analysis is
required prior to re-use of
reclaimed refrigerant. It is
essential that electrical power
is available before the task is
commenced.
• Become familiar with the
equipment and its operation.
• Isolate system electrically.
• Before attempting the
procedure ensure that:
– mechanical handling
equipment is available, if
required, for handling
refrigerant cylinders.
– all personal protective
equipment is available and
being used correctly.
– the recovery process is
supervised at all times by a
competent person.
– recovery equipment and
cylinders conform to the
appropriate standards.
• Pump down refrigerant system,
if possible.
• If a vacuum is not possible,
make a manifold so that
refrigerant can be removed
from various parts of the
system.
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