mundoclima MH-20-V9 Manual De Instalación Y Usuario página 29

LFL of the refrigerant and shall be calibrated to the refrigerant employed and the appropriate
percentage of gas (25% maximum) is confirmed. Leak detection fluids are suitable for use with
most refrigerants but the use of detergents containing chlorine shall be avoided as the chlorine
may react with the refrigerant and corrode the copper pipe-work.
If a leak is suspected ,all naked flames shall be removed or extinguished. If a leakage of refrigernat
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 . Oxygen free
nitrogen(OFN) shall then be purged through the system both before and during the brazing process.
15. Removal and 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 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. 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.
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