INFORMATION SERVICING
15. Removal and evacuation
When breaking into the refrigerant circuit to make repairs of for any other purpose conventional procedures shall be used, How-
ever, 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 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 closed to any ignition sources and there is ventilation available.
16. 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 minimize 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.
17. Decommissioning
Before carrying out this procedure, it is essential that the technician is completely familiar with the equipment and all its detail.
All refrigerants should be collected and handled in accordance with applicable laws and regulations. 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 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 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).
i) Do not exceed the maximum working pressure of the cylinder, even temporarily.
j) 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.
k) Recovered refrigerant shall not be charged into another refrigeration system unless it has been cleaned and checked.
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Summary of Contents for 20-046
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