Idiomas disponibles
Idiomas disponibles
ENGLISH
3. Repair of intrinsically safe components
-
Do not apply any permanent inductive or capacitive load to the circuit without ensuring
that it will not exceed the permissible voltage and current rating for the equipment in use.
-
Intrinsically safe components are the only type of components that can be worked on
in a flammable atmosphere. The test instrumentation must have the correct assigned
features.
-
Replace components only with parts specified by the manufacturer. Other parts can ignite
the refrigerant in the atmosphere from a leak.
4. Wiring
Verify that the wiring is not subject to wear, corrosion, excessive pressure, vibration, sharp
edges, or any other environmental effects. The verification should also take into account the
effects of ageing or continuous vibration from sources such as compressors or fans.
5. Detection of flammable refrigerants
Under no circumstances should potential ignition sources be used in the search for or detection
of refrigerant leaks. Do not use a halide lamp or any other detector using a naked flame.
6. Leak-detection methods
-
The following leak-detection methods are considered acceptable for systems containing
flammable refrigerants.
-
Electronic leak detectors should be used to detect flammable refrigerants, but the
sensitivity may not be adequate, or may need recalibration (the detection equipment should
be calibrated in a refrigerant-free area). Ensure that the detector is not a potential ignition
source and that it is suitable for the refrigerant used. The leak-detection equipment must
be set to a percentage of the lower flammability limit of the refrigerant and calibrated for
the refrigerant used with the appropriate percentage of gas (maximum 25%) confirmed.
-
Leak-detection fluids are suitable for use with most refrigerants, but the use of detergents
containing chlorine must be avoided, as chlorine can react with the refrigerant and corrode
copper pipes.
-
If a leak is suspected, all naked flames must be eliminated/extinguished.
-
If a refrigerant leak is found and requires brazing, all refrigerant must be recovered from
the system, or isolated (by means of shut-off valves) in a part of the system far away from
the leak. Oxygen-free nitrogen must then be purged through the system both before and
during the brazing process.
7. Removal and evacuation
When intervening in the cooling circuit for repairs or any other purpose, conventional
procedures must be followed. However, it is important that best practices are followed, as
flammability is a matter to be taken seriously. The following procedure is to be followed:
1.
Remove the refrigerant.
72
FORCECLIMA 12600 SOUNDLESS HEATING
2.
Purge the circuit with inert gas.
3.
Evacuate.
4.
Purge again with inert gas.
Open the circuit by cutting or brazing.
5.
-
The refrigerant charge must be recovered from the correct recovery cylinders. The system
must be flushed with oxygen-free nitrogen to render the unit safe. This process may need
to be repeated several times. Oxygen or compressed air must not be used for the task.
-
Cleanliness must be achieved by breaking the vacuum in the system with oxygen-
free nitrogen and continuing to fill until working pressure is reached, then venting to
atmosphere, and finally pushing to a vacuum. This process must be repeated until there
is no refrigerant left in the system. When using the oxygen-free nitrogen end-charge,
the system must be vented to atmospheric pressure to allow for work. This operation is
absolutely vital if brazing operations are to take place on pipes.
-
Ensure that the vacuum pump outlet is not near any source of ignition and that ventilation
is available.
8. Loading procedure
In addition to conventional loading procedures, the following requirements must be followed.
-
Ensure that no contamination of different refrigerants occurs when using the loading
equipment. Hoses or lines should be kept as short as possible to minimise the amount of
refrigerant contained in them.
-
Cylinders must be kept in an upright position.
-
Ensure that the refrigeration system is grounded before loading the system with
refrigerant.
-
Tag the system when charging is complete (if not already).
-
Extreme care must be taken to avoid overfilling the cooling system.
Before reloading, the system must be pressure-tested with oxygen-free nitrogen. The system
shall be leak-tested upon completion of loading, but prior to commissioning. A subsequent
leakage test must be carried out before leaving the site.
9. Commissioning
Before performing this procedure, it is essential that the technician is thoroughly familiar with
the equipment and all its details. It is recommended good practice that all refrigerants are
safely recovered. Before the task is carried out, a sample of oil and refrigerant should be taken
in case an analysis is required before the recovered coolant is reused. It is essential for there to
be power before starting with the task.
A. It is important to get familiar with the equipment and its operation.
B. Electrically isolate the system.
C. Before attempting the procedure, ensure that:
-
the mechanical-handling equipment is available, if required, for the handling of refrigerant
cylinders;
ENGLISH
FORCECLIMA 12600 SOUNDLESS HEATING
73
