Trane ProSpace PTEG0701GAA Installation, Operation And Maintenance Manual page 38

T T r r o o u u b b l l e e s s h h o o o o t t i i n n g g a a n n d d R R e e s s o o u u r r c c e e s s
N N o o t t e e s s : : Examples of leak detection fluids are:
• bubble method,
• fluorescent method agents.
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. Removal of
refrigerant shall be according to Clause Removal and
evacuation.
R R e e m m o o v v a a l l a a n n d d e e v v a a c c u u a a t t i i o o n n
When breaking into the refrigerant circuit to make
repairs – or for any other purpose –conventional
procedures shall be used. However, for flammable
refrigerants it is important that best practice be
followed, since flammability is a consideration. The
following procedure shall be adhered to:
1. safely remove refrigerant following local and
national regulations;
2. purge the circuit with inert gas;
3. evacuate (optional for A2L);
4. purge with inert gas (optional for A2L);
5. open the circuit by cutting or brazing.
The refrigerant charge shall be recovered into the
correct recovery cylinders if venting is not allowed by
local and national codes. For appliances containing
flammable refrigerants, the system shall be purged
with oxygen-free nitrogen to render the appliance safe
for flammable refrigerants. This process might need to
be repeated several times. Compressed air or oxygen
shall not be used for purging refrigerant systems.
For appliances containing flammable refrigerants,
refrigerants purging shall be achieved by breaking the
vacuum in the system with oxygen-free nitrogen and
continuing to fill until the working pressure is achieved,
then venting to atmosphere, and finally pulling down
to a vacuum (optional for A2L). This process shall be
repeated until no refrigerant is within the system
(optional for A2L). When the final oxygen-free nitrogen
charge is used, the system shall be vented down to
atmospheric pressure to enable work to take place.
Ensure that the outlet for the vacuum pump is not close
to any potential ignition sources and that ventilation is
available.
C C h h a a r r g g i i n n g g p p r r o o c c e e d d u u r r e e s s
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.
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• Cylinders shall be kept in an appropriate position
according to the instructions.
• Ensure that the refrigeration 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
refrigeration system.
Prior to recharging the system, it shall be pressure
tested with the appropriate purging gas.
The system shall be leak-tested on completion of
charging but prior to commissioning. A follow up leak
test shall be carried out prior to leaving the site.
D D e e c c o o m m m m i i s s s s i i o o n n i i n n g g
Before carrying out this procedure, it is essential that
the technician is completely familiar with the
equipment and all its detail. It is recommended good
practice that all refrigerants are recovered safely. Prior
to the task being carried out, an oil and refrigerant
sample shall be taken in case analysis is required prior
to reuse of reclaimed refrigerant. It is essential that
electrical power is available before the task is
commenced.
1. Become familiar with the equipment and its
operation.
2. Isolate system electrically.
3. Before attempting the procedure, ensure that:
• mechanical handling equipment is available, if
required, 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.
4. Pump down refrigerant system, if possible.
5. If a vacuum is not possible, make a manifold so that
refrigerant can be removed from various parts of
the system.
6. Make sure that cylinder is situated on the scales
before recovery takes place.
7. Start the recovery machine and operate in
accordance with manufacturer's instructions.
8. Do not overfill cylinders. (No more than 80 %
volume liquid charge).
9. Do not exceed the maximum working pressure of
the cylinder, even temporarily.
10. When the cylinders have been filled correctly and
the process completed, make sure that the cylinders
and the equipment are removed from site promptly
and all isolation valves on the equipment are closed
off.
PTAC-SVX004A-EN