LG THERMA V HN0613M Installation Manual page 15

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.
• Removal and evacuation
When breaking into the refrigerant circuit to make repairs – or
for any other purpose - conventional procedures shall be used.
However, it is important that best practice is followed since
flammability is a consideration.
The following procedure shall be adhered to:
- Remove refrigerant
- Purge the circuit with inert gas
- Evacuate
- Purge again with inert gas
- Open the circuit by cutting or brazing.
The refrigerant charge shall be recovered into the correct
recovery cylinders. The system shall be "flushed" with OFN to
render the unit safe.
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 and continuing to fill until the working
pressure is achieved, then venting to atmosphere, and finally
pulling down to a vacuum.
This process shall be repeated until no refrigerant is within the
system. When the final OFN charge is used, the system shall
be vented down to atmospheric pressure to enable work to
take place. This operation is absolutely vital if brazing
operations on the pipe-work are to take place. Ensure that the
outlet for the vacuum pump is not close to any ignition
sources and there is ventilation available.
SAFETY INSTRUCTIONS
15