Orbegozo ADR 122 Manual De Instrucciones página 31

ADR 122 ADR 128 ADRW 120 ADRW 125
may not be adequate, or may need recalibration. (Detection equipment shall be calibrated in a
refrigerant-free area.) Ensure that the detector is not a potential source of ignition and is suitable for
the refrigerant used. Leak detection equipment shall be set at a percentage of the 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/extinguished. If
a leakage of refrigerant 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.
7 REMOVAL AND EVACUATION
When breaking into the refrigerant circuit to make repairs – or 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 pipework are
to take place.
Ensure that the outlet for the vacuum pump is not close to any ignition sources and there is ventilation
available.
8 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.
9 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.
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