Emerson DFR29 Manuel De L'utilisateur page 34

SAFETY PRECAUTIONS
preventing the ingress of flammable atmospheres. Replacement parts shall be in accordance
with the manufacturer's specifications.
NOTE: The use of silicon sealant may inhibit the effectiveness of some types of leak detection
equipment. Intrinsically safe components do not have to be isolated prior to working on them.
8.Repair to intrinsically safe components
Do not apply any permanent inductive or capacitance loads to the circuit without ensuring tha t
this will not exceed the permissible voltage and current permitted for the equipment in u se.
Intrinsically safe components are the only types that can be worked on while live in th e
presence of a flammable atmosphere. The test apparatus shall be at the correct rating .
Replace components only with parts specified by the manufacturer. Other parts may result in
the ignition of refrigerant in the atmosphere from a leak.
9.Cabling
Check that cabling will not be subject to wear, corrosion, excessive pressure, vibration, shar p
edges or any other adverse environmental effects. The check shall also take into account th e
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) sh all
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 t he
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 appropria te
percentage of gas (25 % maximum) is confirmed. Leak detection fluids are suitable for use w ith
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 require s
brazing, all of the refrigerant shall be recovered from the system, or isolated (by means of shu t
off valves) in a part of the system remote from the leak. Oxygen free nitrogen (OFN) shall th en
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 conventiona l
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:
Re move refrigerant ;
Pu rge the circuit with inert ga s;
Ev acuate ;
Pu rge again with inert g as;
Op en the circuit by cutting or brazing .
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