Gree GUD35ZD/A-T Owner's Manual page 62

DC Inverter U-match Series Floor Ceiling Type Unit
5.4.4 Cabling
Check that cabling will not be subject to wear, corrosion, excessive pressure,
vibration, sharp edges or any other adverse environmental effects. The check
shall also take into account the effects of ageing or continual vibration from
sources such as compressors or fans.
5.4.5 Detection of Flammable Refrigerants
Under no circumstances shall potential sources of ignition be used in the
searching for or detection of refrigerant leaks. A halide torch (or any other
detector using a naked flame) shall not be used.
5.4.6 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：
(1) Remove refrigerant;
(2) Purge the circuit with inert gas;
(3) Evacuate;
(4) Purge again with inert gas;
(5) 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
pipework are to take place.
Ensure that the outlet for the vacuum pump is not close to any ignition
sources and there is ventilation available.
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