Saneo A010A-12C Manual page 59

Intrinsically safe components are the only types that can be worked on when they are
energised in a flammable atmosphere. The test equipment must have the correct rated
characteristics.
Replace components only with parts specified by the manufacturer. Other parts can cause
the refrigerant to ignite in the atmosphere as a result of a leak.
- Cabling
Check that the wiring will not be subjected to wear, corrosion, excessive pressure,
vibration, sharp edges or any other adverse environmental effects. The verification must
also take into account the effects of aging or continuous vibration from sources such as
compressors or fans.
- Detection of flammable refrigerants
Under no circumstances should potential ignition sources be used to search for or detect
refrigerant leaks. A haloid lamp (or any other detector using an open flame) must not be
used.
- 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 their
sensitivity may not be adequate or may require recalibration. (Detection equipment must
be calibrated in an area without refrigerant.) Ensure 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 LFL of the refrigerant and must be calibrated to the fluid used
and the appropriate percentage of gas (maximum 25%) is confirmed.
Leak detection fluids are suitable for use with most refrigerants, but the use of detergents
containing chlorine should be avoided as chlorine can react with the refrigerant and
corrode the copper piping.
In the event of a suspected leak, all open flames must be eliminated/extinguished.
If a refrigerant leak is found and brazing is required, all the refrigerant in the system must
be recovered or isolated (by means of shut-off valves) in a part of the system remote from
the leak. The oxygen-free nitrogen must then be purged through the system both before
and during the brazing process.
- Removal and evacuation
When working on the refrigerant circuit for repairs - or for any other purpose - conventional
procedures must be used. However, it is important to follow best practice as flammability
is a concern. The following procedure must be followed:
- remove the refrigerant;
- purge the circuit with an inert gas;
- proceed with the evacuation;
- purge again with an inert gas;
- open the circuit by cutting or soldering.