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4. Ventilated area
Ensure that the area is in the open or that it it adequately ventilated before breaking
into the system or conducting any hot work. A degree of ventilation shall continue
during the period that the work is carried out. The ventilation should safely disperse
any released refrigerant and preferably expel it externally into the atmosphere.
5. Cabling
Check that cabling will not be subject to wear, corrosion, excessive pressure,
vibration, sharp edges or any other adverse environmental e ects. The check shall
also take into account the e ects of aging or continual vibration from sources such
as compressors or fans.
6. 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.
The following leak detection methods are deemed acceptable for refrigerant
systems. Electronic leak detectors may be used to detect refrigerant leaks but, in
the case of FLAMMABLE 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 confirmed.
Leak detection fluids are also 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.
NOTE Examples of leak detection fluids are
- bubble method,
- fluorescent method agents.
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 o valves) in a part of
the system remote from the leak. See the following instructions of removal of
refrigerant.
7. Removal and evacuation
When breaking into the refrigerant circuit to make repairs - or for any other purpose
conventional procedures shall be used. However, for flammable refrigerants it is
important that best practice be followed, since flammability is a consideration.
The following procedure shall be adhered to:
safely remove refrigerant following local and national regulations;
evacuate;
purge the circuit with inert gas (optional for A2L);
evacuate (optional for A2L);
continuously flush or purge with inert gas when using flame to open circuit; and
open the circuit.
The refrigerant charge shall be recovered into the correct recovery cylinders if
venting is not allowed by local and national codes. For appliances containing
flammable refrigerants, the system shall be purged with oxygen-free nitrogen to
render the appliance safe for flammable refrigerants. This process might need to
be repeated several times. Compressed air or oxygen shall not be used for purging
refrigerant systems.
For appliances containing flammable refrigerants, refrigerants purging shall be
achieved by breaking the vacuum in the system with oxygen-free nitrogen and
continuing to fill until the working pressure is achieved, then venting to atmosphere,
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