Beko BBVHO 090 User Manual page 31

6 Instructions for servicing (R32)
19. Cabling
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.
20. Detection of 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.
21. 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 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 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
Split type air conditioner / User Manual
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.
22. 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 inflammability 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.
31 / 120 EN