ENGLISH
EN - 14
26. DETECTION OF FLAMMABLE REFRIGERANTS
Under no circumstances shall potential sources of ignition be used in the
searching for or detection of refrigerant leaks.
Ahalidetorch(oranyotherdetectorusinganakedame)shallnotbeused.
27. LEAK DETECTION METHODS
The following leak detection methods are deemed acceptable for systems
containingammablerefrigerants.
Electronicleakdetectorsshallbeusedtodetectammablerefrigerants,but
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
appropriatepercentageofgas(25%maximum)isconrmed.
Leakdetectionuidsaresuitableforusewithmostrefrigerantsbuttheuseof
detergents containing chlorine shall be avoided as the chlorine may react with
the refrigerant and corrode the copper pipe-work.
Ifaleakissuspected,allnakedamesshallberemoved/extinguished.
Ifaleakageofrefrigerantisfoundwhichrequiresbrazing,alloftherefrigerant
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
beforeandduringthebrazingprocess.
28. REMOVAL AND EVACUATION
When breaking into the refrigerant circuit to make repairs or for any other
purpose conventional procedures shall be used.
However,itisimportantthatbestpracticeisfollowedsinceammabilityisa
consideration.
The following procedure shall be adhered to:
• Removerefrigerant;
• Purgethecircuitwithinertgas;
• Evacuate;
• Purgeagainwithinertgas;
• Openthecircuitbycuttingorbrazing.
The refrigerant charge shall be recovered into the correct recovery cylinders.
ThesystemshallbeushedwithOFNtorendertheunitsafe.
This process may need to be repeated several times.
Compressed air or oxygen shall not be used for this task.
Flushing shall be achieved by breaking the vacuum in the system with OFN
andcontinuingtolluntiltheworkingpressureisachieved,thenventingto
atmosphere,andnallypullingdowntoavacuum.
This process shall be repeated until no refrigerant is within the system. When
thenalOFNchargeisused,thesystemshallbeventeddowntoatmospheric
pressure to enable work to take place.
Thisoperationisabsolutelyvitalifbrazingoperationsonthepipe-workareto
take place.
Ensure that the outlet for the vacuum pump is not close to any ignition sources
and there is ventilation available.