Tabla de contenido
Idiomas disponibles
Idiomas disponibles
27. LEAK DETECTION METHODS
The following leak detection methods are deemed acceptable for systems containing flam-
mable refrigerants.
Electronic leak detectors shall be used to detect flammable refrigerants, but the sensitivity
may not be adequate, or may need re-calibration. (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 cor-
rode 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 re-
covered 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 dur-
ing the brazing process.
28. REMOVAL AND EVACUATION
When breaking into the refrigerant circuit to make repairs or for any other purpose conven-
tional 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 close to any ignition sources and there is
ventilation available.
29. CHARGING PROCEDURES
In addition to conventional charging procedures, the following requirements shall be fol-
lowed.
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 refriger-
ant 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).
EN - 9
DOLCECLIMA BREZZA
Tabla de contenido
