DC Inverter U-match Series Floor Ceiling Type Unit 
28 
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 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. 
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 off valves) in a part of the 
system remote from the leak. Oxygen free nitrogen (OFN) shall then be purged 
through the system both before and during the brazing process. 
3.2.5 Refrigerant Adding 
Before and during operation, use an appropriate refrigerant leak detector to monitor 
the  operation  area  and  make  sure  the  technicians  can  be  well  aware  of  any 
potential or actual leakage of inflammable gas. Make sure the leak detecting device 
is applicable to inflammable refrigerant. For example, it should be free of sparks, 
completely sealed and safe in nature.