
96
GB
DEHUMIDIFIER / AIR PURIFIER
can be worked on while live in the presence of a
fl
ammable atmosphere. The
test apparatus shall be at the correct rating. Replace components only with
parts speci
fi
ed by the manufacturer. Other parts may result in the ignition of
refrigerant in the atmosphere from a leak.
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.
Detection of
fl
ammable refrigerants
Under no circumstances shall potentially sources of ignition be used in the
searching for or detection of refrigerant leaks. A halide torch (or any other
detector using a naked
fl
ame) shall not be used.
Leak detection methods
The following leak detection methods are deemed acceptable for all refrigerant
systems.
Electronic leak detectors may be used to detect refrigerant leaks but, in the
case of
fl
ammable refrigerants, 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 con
fi
rmed.
Leak detection
fl
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
fl
ames shall be removed/extinguished.
If a leakage of refrigerant is found which requires brazing, all of the refrigerants
shall be recovered from the system, or isolated (by means of shut off valves) in
a part of the system remote from the leak. For appliances containing
fl
ammable
refrigerants, oxygen free nitrogen (OFN) shall then be purged through the
system both before and during the brazing process.