30
atmosphere. The test apparatus must have correct nominal values. Replace components
only with parts specified by the manufacturer. Other parts can cause the refrigerant to
ignite in the atmosphere from a leak.
4. WIRING
Verify that the wiring is not subject to wear, corrosion, excessive pressure, vibration,
sharp edges, or other adverse environmental effects. The control must also take into
account the effects of aging or continuous vibrations from sources such as compressors
or fans.
5. DETECTION OF FLAMMABLE REFRIGERANTS
Under no circumstances should potential ignition sources be used in searching for or
detecting refrigerant leaks. Do not use a halide torch (or any other detector that uses
a naked flame).
6. LEAK DETECTION METHODS
The following leak detection methods are considered acceptable for systems containing
flammable refrigerants. Electronic leak detectors must be used to detect flammable
refrigerants, but sensitivity may not be adequate or may require recalibration. (The
detection equipment must be calibrated in an area free of refrigerant.) Make sure
that the detector is not a potential source of ignition and is suitable for the refrigerant
used. The leak detection equipment must be set to a percentage of the LFL of the
refrigerant and calibrated to the refrigerant used and the appropriate percentage
of gas confirmed (25% maximum). Fluid leak detectors are suitable for use with most
refrigerant fluids but the use of detergents that contain bleach must be avoided as
they can react with the refrigerant and corrode the copper piping network. If a leak
is suspected, all naked flames must be removed / extinguished. If a refrigerant leak
that requires brazing is detected, all refrigerant must be recovered from the system or
isolated (via shut-off valves) in a part of the system away from the leak. Oxygen Free
Nitrogen (OFN) must therefore be purged through the system both before and during
the brazing process.
GB
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