Sharp UD-T10A Gebruikershandleiding pagina 8
Beschikbare talen
Beschikbare talen
8
Engineer information
1. Cabling
Ensure that any cabling is not subject to wear, corrosion, excessive
pressure, vibration, sharp edges or any other adverse environmental
eff ects. Also be aware of any eff ects cause by aging or continual leaks. A
halide torch (or any other detector using a naked fl ame) must not be used.
2. Detection of fl ammable refrigerants
DO NOT use any possible sources of ignition to search for refrigerant leaks.
A halide torch (or any other detector using a naked fl ame) must not be
used.
3. Leak detection methods
The following leak detection methods are deemed acceptable for systems
containing fl ammable refrigerants.
Electronic leak detectors can be used to detect fl ammable 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
confi rmed.
Leak detection fl uids are suitable for use with most refrigerants but the use
of detergents containing chlorine must be avoided as the chlorine may
react with the refrigerant and corrode the copper pipework.
If a leak is suspected, all naked fl ames must be removed/extinguished.
If a leakage of refrigerant is found which requires brazing, all of the
refrigerant gas must be recovered from the system, or isolated (by means
of shut off valves) in a part of the system both before and during the
brazing process.
4. 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 fl ammability 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 "fl ushed' 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 fi ll until the working pressure is achieved, then venting
to atmosphere, and fi nally pulling down to a vacuum. This processing shall
be repeated until no refrigerant is within the system. When the fi nal OFN
charge is used, the system shall be vented down to atmospheric pressure
to enable work to take place. This operation is 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.
5. Charging procedures
In addition to conventional charging procedures, the following
requirements shall be followed.
Ensure that contamination of diff erent refrigerants does not occur when
using charging equipment.
Hoses or lines shall be as short as possible to minimize the amount of
refrigerant contained in them.
Cylinders must 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 must be taken not to overfi ll the refrigeration system.
Prior to recharging the system is must be pressure tested with OFN.
The system must be leak tested on completion of charging but prior to
commissioning. A follow up leak test must be carried out prior to leaving
the site.
6. Decommissioning
Before carrying out this procedure, it is essential that the engineer
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 must be taken
is case analysis is required prior to re-use of reclaimed refrigerant. It is
essential that electrical power is available before the task is commenced.
Become familiar with the equipment and its operation.
Isolate system electrically.
Before attempting the procedure ensure that:
Mechanical handling equipment is available and being used correctly the
recovery process is always supervised by a competent person recovery
equipment and cylinders conform to the appropriate standards.
a) Pump down refrigerant system, if possible.
b) If a vacuum is not possible, make a manifold so that refrigerant can
be removed from various parts of the system.
c) Make sure that cylinder is situated on the scales before recovery
takes place.
d) Start the recovery machine and operate in accordance with
manufacturer's instructions.
e) Do not overfi ll cylinders. (No more than 80% volume liquid charge).
f ) Do not exceed the maximum working pressure of the cylinder, even
temporarily.
g) When the cylinders have been fi lled correctly and the process
completed, make sure that the cylinders and the equipment
are removed from site promptly and all isolation valves on the
equipment are closed off .
h) Recovered refrigerant shall not be charged into another
refrigeration system unless it has been cleaned and checked.
7. Labelling
Equipment shall be labeled stating that it has been de-commissioned
and emptied of refrigerant. The label shall be dated and signed. Ensure
that there are labels on the equipment stating the equipment contains
fl ammable refrigerant.
8. Recovery
When removing refrigerant from a system, either for servicing or
decommissioning, it is recommended good practice that all 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 labeled for that refrigerant, i.e. special
cylinders for the recovery of refrigerant. Cylinders shall be complete with
pressure relief valve and associated shut-off 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 with a
set of instructions concerning the equipment that is at hand and shall be
suitable for the recovery of fl ammable refrigerants.
In addition, a set of calibrated weighing scales shall be available and in
good working order. Hoses shall be complete with leak-free disconnect
couplings and good condition. Before using the recovery machine, check
that it is in satisfactory 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 of 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 refrigerants 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 fl ammable
refrigerant does not remain within the lubricant. The evacuation process
