Qlima PES 7125 Instrucciones De Uso página 88

6 LEAK DETECTION METHODS
The following leak detection methods are deemed acceptable for systems containing flammable
refrigerants. Electronic leak detectors shall be used to detect flammable refrigerants, but the sensitivity
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 pipework.
lf a leak is suspected, all open flames shall be removed/extinguished.
lf 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 tor the vacuum pump is not close to any ignition sources and !here 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. lt 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. lt is essential that 4 GB electrical power is available before the task is commenced.
a)
b)
c)
GB
88
Become familiar with the equipment and its operation.
lsolate system electrically.
Before attempting the procedure ensure that: mechanical handling equipment is available, if