Bimar DEU315 Notice D'instructions page 46

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.
Removal and evavuation. 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