Inventum AC127W Mode D'emploi page 22

CAUTION: The use of silicone containing sealing agents could disrupt the operation of some types of leak detection
equipment. Intrinsically safe components do not have to be disconnected before working at them.
8. Repairs to intrinsically safe components (Appendix DD.5)
Do not connect permanently inductive or capacitive loads to the circuit without checking whether the allowed voltages and
currents for the equipment used are exceeded.
Intrinsically safe components are the only types of component at which you are allowed to work while they are live in the
presence of combustible ambient air. Only use test equipment with the correct certifications.
Only replace components by parts that correspond with the manufacturer's specifications. The use of deviating parts could
cause fire when refrigerant escapes to the ambient air as a result of a leak.
9. Cables (Appendix DD.6)
Check that the cables are not exposed to wear, corrosion, excessive pressure, vibrations, sharp edges or other negative
ambient influences. When checking, also consider the consequences of ageing and constant vibration of compressors or fans.
10. Detection of combustible refrigerants (Appendix DD.7)
Never use potential ignition sources when looking for or tracing refrigerant leaks. Do not use a halogen lam (or any other
detector with an open flame).
11. Leak detection methods (Appendix DD.8)
The following leak detection methods may be used for systems containing combustible refrigerants.
Preferably use electronic leak detectors to detect combustible refrigerants. Sometimes the sensitivity of such equipment
is not sufficient, or they must be recalibrated. (Always calibrate detection equipment in a room that is free from refrigerant.)
Check that the detector is not a potential ignition source and that it is suitable for the refrigerant used. Adjust the leak
detection equipment at a percentage of the refrigerant's LFL (lower flammable limit) and calibrate the equipment to the
refrigerant used and the correct gas percentage (maximum 25%).
Leak detection liquids are also suitable for use with most refrigerants, but avoid the use of chlorinated substances, as the
chlorine could also react with the refrigerant and affect the copper piping.
If a leak is suspected, all open flames must be extinguished or removed.
If a refrigerant leak is found that requires soldering, all refrigerant should first be drained from the system, or the refrigerant
should be isolated (by means of valves) in a section of the system away from the leak. Then flush the system with oxygen free
nitrogen (OFN), both prior to and during the soldering process.
12. Draining and emptying (Appendix DD.9)
When opening a cooling circuit in order to perform repairs - as well as for all other purposes - the correct regulations and
procedures should be observed at all times. In addition, always try to work as safely as possible, due to the flammability of the
refrigerants. For that reason, always use the following procedure:
• Remove the refrigerant;
• Flush the circuit with inert gas;
• Empty the system;
• Flush once more with inert gas;
• Open the circuit by sawing or soldering.
Collect the refrigerant in a suitable storage container. Flush the system with OFN (oxygen free nitrogen) to make the system
safe. It is possible that you must repeat this process a few times. Never use compressed air or oxygen to flush a system.
Flush the vacuum system by allowing OFN to flow into it and then fill the system with OFN until the operating pressure is
achieved. Then allow this to escape to the atmosphere and make the system vacuum again. Repeat this process until there is
no more refrigerant in the system. After the last OFN flush, the system must be de-aerated to atmospheric pressure to make
the work possible. This is an absolute condition when soldering work has to take place at the piping.
Ensure that the exhaust of the vacuum pump is not in the vicinity of ignition sources and that the surrounding area is
sufficiently ventilated.
13. Filling procedures (Appendix DD.10)
In addition to the standard procedures when filling, also observe the following requirements.
- When using the filling equipment, prevent different refrigerants from getting mixed. Hoses and pipes must be as short as
possible to minimise the amount of refrigerant that they contain.
- Always place cylinders upright.
- Earth the cooling system before filling the system with refrigerant.
- Mark the system when it is filled (if this has not yet been done).
- Ensure the cooling system is not excessively filled.
Perform a pressure test with OFN (oxygen free nitrogen) before filling the system. Check the system for leaks after filling,
but before commissioning. Always perform a final leak test before leaving the location.
14. Decommissioning (Appendix DD.11)
In order to perform this procedure, it is essential that the technician has fully familiarised himself with the equipment and all
its parts. It is always recommended to drain and dispose the refrigerants used safely. Prior to the work, always take an oil and
refrigerant sample when reuse of the drained refrigerant requires prior analysis. It is essential to check whether there is a power
supply present, before starting the work.
22 • English