HTW HTWDO16A3 Manual De Usuario E Instalacion página 58

If compressors or compressor oils are to be removed, ensure that
they have been evacuated to an acceptable level to make certain
that flammable refrigerant does not remain within the lubricant.
The evacuation process shall be carried out prior to returning the
compressor to the suppliers. Only electric heating to the
compressor body shall be employed to accelerate this process.
When oil is drained from a system, it shall be carried out safely.
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.
23