conventional procedures must be used. However, it is important to follow best
practice as flammability is a concern. The following procedure must be followed:
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remove the refrigerant;
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purge the circuit with an inert gas;
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evacuate;
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purge again with an inert gas;
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open the circuit by cutting or soldering.
The refrigerant charge must be collected in correct recovery bottles. The system must
be drained with oxygen-free nitrogen to make the element safe. This process may
have to be repeated several times. Do not use compressed air or oxygen for this task.
Drainage must be achieved by cutting the vacuum in the system with oxygen-free
nitrogen and continuing to fill until the operating pressure is reached, then venting
into the atmosphere and finally creating the vacuum. This process must be repeated
until there is no refrigerant left in the system. When the final oxygen-free nitrogen
charge is used, the system must be returned to atmospheric pressure to allow
operations to proceed. This operation is absolutely vital if brazing operations are to
take place on the pipes.
Make sure that the outlet of the exhaust pump is not close to an ignition source and
that there is ventilation.
Loading procedures
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In addition to conventional loading procedures, the following requirements must be
met.
Ensure that no contamination of different refrigerants occurs during the use of the
loading equipment. The pipes or ducts should be as short as possible to minimize the
amount of refrigerant they contain.
The bottles must be kept in an upright position.
Ensure that the refrigeration system is grounded before charging the system with the
refrigerant.
Label the system when loading is complete (if not already done).
Be careful not to allow the refrigeration system to overflow.
Before recharging the system, its pressure must be tested with oxygen-free nitrogen.
The system shall be leak tested at the end of loading but before commissioning. A
leak test must be performed before leaving the site.
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Decommissioning of the plant
Before performing this procedure, it is essential that the technician is fully familiar