5
Wiring
•
Check 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.
Detection of flammable refrigerant
•
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.
•
The following leak detection methods are deemed acceptable for all refrigerant
systems.
•
Electronic leak detectors may be used to detect refrigerant leaks but, in the ease
of flammable refrigerants, the sensitivity may not be adequate, or may need re-
calibration. (Detection equipment shall be calibrated in a refrigerant-tree 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 also 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 names 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.
Removal and discharge
•
When breaking into the refrigerant circuit to make repairs - or for any other purpose
- conventional procedures shall be used. However, for flammable refrigerants 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 (optional for A2L);
-
evacuate (optional for A2L);
-
purge with inert gas (optional for A2L);
-
open the circuit by cutting or brazing.
• The refrigerant charge shall be recovered into the correct recovery cylinders. For
appliances containing flammable refrigerants other than A2L refrigerants, the
system shall be purged with oxygen-free nitrogen to render the appliance safe
for flammable refrigerants. This process may need to be repeated several times.
Compressed air or oxygen shall not be used for purging refrigerant systems.
Loading procedures
•
Ensure that the outlet tor the vacuum pump is not close to any potential ignition
sources and that ventilation is available.
•
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 in an appropriate position according to the instructions.
-
Ensure that the refrigerating 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 refrigerating system.
•
Prior to recharging the system, it shall be pressure-tested with the appropriate
purging gas. 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.
Dismantling
•
Before carrying out this procedure, it is essential that the technician is completely
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