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Replace components only with parts specified by manufacturer. Other parts may result in the ignition of
refrigerant in the atmosphere from a leak.
11.Cabling
C
heck that cabling will not be subject to wear, corrosion, excessive pressure, vibration, sharp edges or
any other adverse environmental effects. The check shall also take into account the effects of aging or
continual vibration from sources such as compressors or fans.
12.Leakage detection for flammable refrigerants
Under no circumstances shall potential sources of ignition be used in the searching for or detection of
refrigerant leaks. A halide torch (or any other detector using a naked flame) shall not be used.
13.Leak detection methods
The following leak detection methods are acceptable for systems containing flammable refrigerant.
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 detector is not a potential source of ignition and is suitable for the refrigerant used.
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 leak of refrigerant is found which requires brazing, all of the refrigerant shall be recovered from the
system. Oxygen free nitrogen (OFN) shall then be purged through the system both before and during the
brazing process.
14.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 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.
15.Refrigerant 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 commissioning. A follow up leak test shall be carried out prior to leaving the
site.
16.Decommissioning
Before carrying out this procedure, it is essential that 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
