Gree GWH09AVCXB-K6DNA1B/I Owner's Manual page 31

Specialist's Manual
most refrigerants but the use of detergents contain-
ing 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 re-
moved/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. For appliances containing flammable refriger-
ants, 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 pro-
cedures shall be used. However, for flammable
refrigerants 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 with inert gas;
●
open the circuit by cutting or brazing.
●
The refrigerant charge shall be recovered into the
correct recovery cylinders. For appliances contain-
ing flammable refrigerants, 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
purging refrigerant systems.
For appliances containing flammable refrigerants,
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 atmo-
spheric pressure to enable work to take place.
This operation is absolutely vital if brazing opera-
tions on the pipe-work are to take place.
Ensure that the outlet for the vacuum pump is not
close to any ignition sources and that ventilation is
available.
● Charging procedures
In addition to conventional charging procedures, the
following requirements shall be followed.
Ensure that contamination of different refrigerants
●
does not occur when using charging equipment.
Hoses or lines shall be as short as possible to
minimise the amount of refrigerant contained in
them.
Cylinders shall be kept in an appropriate position
●
according to the instructions.
Ensure that the refrigerating system is earthed
●
prior to charging the system with refrigerant.
Label the system when charging is complete (if
●
not already).
Extreme care shall be taken not to overfill the re-
●
frigerating system.
Prior to recharging the system, it shall be pres-
sure-tested with the appropriate purging gas. The
system shall be leak-tested on completion of charg-
ing but prior to commissioning. A follow up leak test
shall be carried out prior to leaving the site.
● Decommissioning
Before carrying out this procedure, it is essential that
the technician is completely familiar with the equip-
ment and all its detail. It is recommended good pr-
actice that all refrigerants are recovered safely.
Prior to the task being carried out, an oil and refri-
gerant sample shall be taken in case analysis is re-
quired prior to re-use of recovered refrigerant. It is
essential that electrical power is available before
the task is commenced.
a) Become familiar with the equipment and its opera-
tion.
b) Isolate system electrically.
c) Before attempting the procedure, ensure that:
– mechanical handling equipment is available, if re-
quired, for handling refrigerant cylinders;
– all personal protective equipment is available and
being used correctly;
– the recovery process is supervised at all times by
a competent person;
– recovery equipment and cylinders conform to the
appropriate standards.
d) Pump down refrigerant system, if possible.
e) If a vacuum is not possible, make a manifold so
that refrigerant can be removed from various parts
of the system.
f) Make sure that cylinder is situated on the scales
before recovery takes place.
g) Start the recovery machine and operate in accor-
dance with manufacturer's instructions.
h) Do not overfill cylinders. (No more than 80% vo-
lume liquid charge).
i) Do not exceed the maximum working pressure of
26