Black & Decker BXDH12E Original Instructions Manual page 8

ENGLISH
(Original instructions)
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. (Detec-
tion equipment shall be calibrated in a refrigerantfree 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. 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 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.
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 cylin-
ders. 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 absolute-
ly vital if brazing operations on the pipework are to take place.
♦ Ensure that the outlet for the vacuum pump is not close to any ignition sources and
there is ventilation available.
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.
DECOMMISSIONING
♦ Before carrying out this procedure, it is essential that the 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 carried out, an oil and
refrigerant sample shall
♦ be taken in case analysis is required prior to reuse of reclaimed refrigerant. It is essen-
tial that electrical power is available before the task is commenced.
♦ a) Become familiar with the equipment and its operation.
♦ b) Isolate system electrically.
♦ c) Before attempting the procedure ensure that: mechanical handling equipment
is available, if required, for handling refrigerant cylinders; all personal protective
equipment is available and being used correctly; the recovery process is supervised
at all times by a competent person; recovery equipment and cylinders conform to the
appropriate standards.
♦ d) Pump down refrigerant system, if possible.
♦ e) If a vacuum is not possible, make a manifold so that refrigerant can be removed
from various parts of the system.
♦ f) Make sure that cylinder is situated on the scales before recovery takes place.
♦ g) Start the recovery machine and operate in accordance with manufacturer's instruc-
tions.
♦ h) Do not overfill cylinders. (No more than 80 % volume liquid charge).
♦ i) Do not exceed the maximum working pressure of the cylinder, even temporarily.
♦ j) When the cylinders have been filled correctly and the process completed, make sure
that the cylinders and the equipment are removed from site promptly and all isolation
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valves on the equipment are closed off.
♦ k) Recovered refrigerant shall not be charged into another refrigeration system unless
it has been cleaned and checked.
LABELLING
♦ Equipment shall be labelled stating that it has been decommissioned and emptied of
refrigerant. The label shall be dated and signed.
♦ Ensure that there are labels on the equipment stating the equipment contains flam-
mable refrigerant.
RECOVERY
♦ When removing refrigerant from a system, either for servicing or decommissioning, it is
recommended good practice that all refrigerants are removed safely. When transferring
refrigerant into cylinders, ensure that only appropriate refrigerant recovery cylinders
are employed. Ensure that the correct number of cylinders for holding the total system
charge are available. All cylinders to be used are designated for the recovered
refrigerant and labelled for that refrigerant (i.e. special cylinders for the recovery of re-
frigerant). Cylinders shall be complete with pressure relief valve and associated shutoff
valves in good working order. Empty recovery cylinders are evacuated and, if possible,
cooled before recovery occurs.
♦ The recovery equipment shall be in good working order with a set of instructions
concerning the equipment that is at hand and shall be suitable for the recovery of flam-
mable refrigerants. In addition, a set of calibrated weighing scales shall be available
and in good working order. Hoses shall be complete with leakfree disconnect couplings
and in good condition. Before using the recovery machine, check that it is in satisfac-
tory working order, has been properly maintained and that any associated electrical
components are sealed to prevent ignition in the event of a refrigerant release. Consult
manufacturer if in doubt.
♦ The recovered refrigerant shall be returned to the refrigerant supplier in the correct
recovery cylinder, and the relevant Waste Transfer Note arranged. Do not mix refrige-
rants in recovery units and especially not in cylinders. If compressors or compressor
oils are to be removed, ensure that they have been evacuated to an acceptable level to
make certain that flammable refrigerant does not remain within the lubricant. The eva-
cuation process shall be carried out prior to returning the compressor to the suppliers.
Only electric heating to the compressor body shall be employed to accelerate this
process. When oil is drained from a system, it shall be carried out safely.
Competence of service personnel
General
♦ Special training additional to usual refrigerating equipment repair procedures is requi-
red when equipment with flammable refrigerants is affected.
♦ In many countries, this training is carried out by national training organisations that
are accredited to teach the relevant national competency standards that may be set in
legislation.
♦ The achieved competence should be documented by a certificate.
Training
♦ The training should include the substance of the following:
♦ Information about the explosion potential of flammable refrigerants to show that flam-
mables may be dangerous when handled without care.
♦ Information about potential ignition sources, especially those that are not obvious, such
as lighters, light switches, vacuum cleaners, electric heaters.
♦ Information about the different safety concepts:
♦ Unventilated – (see Clause GG.2) Safety of the appli-ance does not depend on
ventilation of the housing. Switching off the appliance or opening of the housing has no
significant effect on the safety. Nevertheless, it is possible that leaking refrigerant may
accumulate inside the enclosure and flammable atmosphere will be released when the
enclosure is opened.
♦ Ventilated enclosure – (see Clause GG.4) Safety of the appliance depends on
ventilation of the housing. Switching off the appliance or opening of the enclosure has
a significant effect on the safety. Care should be taken to ensure a sufficient ventilation
before.
♦ Ventilated room – (see Clause GG.5) Safety of the appliance depends on the
ventilation of the room. Switching off the appliance or opening of the housing has no
significant effect on the safety. The ventilation of the room shall not be switched off
during repair procedures.
♦ Information about the concept of sealed components and sealed enclosures according
to IEC 6007915:2010.
♦ Information about the correct working procedures:
Commissioning
♦ Ensure that the floor area is sufficient for the refrigerant charge or that the ventilation
duct is assembled in a correct manner.