Midea CP012IU-PD Owner's Manual page 28

• 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
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 pipe-work are to take place.
Ensure that the outlet for the vacuum pump is not close to any ignition sources and there
is ventilation available.
13. 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 upright.
– 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 OFN. 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.
14. Decommissioning
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 re-use of reclaimed refrigerant. It is
essential that electrical power is available before the task is commenced.
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 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 accordance with manufacturer's instructions.
h) Do not overfill cylinders. (No more than 80 % volume liquid charge).