15.Air evacuation
When breaking into the refrigerant circuit to make repairs of 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 should be recovered in the correct recovery cylinder. OFN should be used to flush
the system to ensure the safety of the equipment. This process may need to be repeated several
times. Compressed air or oxygen cannot be used for this task.
The refrigerant should be recovered in the correct recovery cylinder. OFN should be used to flush
the system to ensure the safety of the equipment. This process may need to be repeated several
times. Compressed air or oxygen cannot be used for this task. Flushing should be achieved by
using OFN to break the vacuum in the system and continue to fill until the working pressure is
reached, then evacuate to atmosphere and finally drop to vacuum. This process should be repea-
ted until there is no refrigerant in the system. When using the final OFN charge, the system should
be vented to atmospheric pressure for operation. If you want to braze the pipe, this operation is
very important. Ensure that the outlet of the vacuum pump does not turn off any ignition source,
and there is a ventilation device.
16. Refrigerant charging
In addition to following the normal charging procedure, the following requirements should also
be followed:
When using refrigerant charging equipment, please ensure that different refrigerants will
not be contaminated. The hose or pipeline should be as short as possible to minimize the
refrigerant content.
Refrigerant tank should be kept upright.
Before charging the refrigerant system, make sure it is grounded.
Mark the system when the charge is complete.
Be extra careful to avoid overfilling the refrigeration system.
Prior to recharging the system it shall be pressure tested with OFN. The system shall be leak
tested on completion of charging but prior to commissioning. A follow up leak test shall be ca-
rried out prior to leaving the site.
.
17. About air conditioner removal
Before performing this step, please confirm that the technician is fully familiar with the equipment
and has relevant qualifications. It is recommended to safely recycle all refrigerants. Before comp-
leting the task, oil and refrigerant samples should be collected. Before the task begins, the power
must be disconnected.
a) Become familiar with the equipment and its operation.
b) Isolate system electrically
c) Before attempting the procedure ensure that
mechanical handling equipment is available, if required, for handling refrigerant cylinders
all personal protetive 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 fromvarious
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 accordance with manufacturer s instructions.
h) Do not overfill cylinders. (No more than 80% volume liquid charge).
