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7
MAINTENANCE
This chiller must be maintained by qualified technicians. Before beginning any work on the system, the personnel
shall assure that all security precautions have been taken.
Personel working on the electrical or the refrigeration components must be authorized, trained and fully qualified.
Maintenance and repair requiring the assistance of other skilled personnel should be carried out under the supervision of
the person competent in the use of flammable refrigerants. Any person conducting servicing or maintenance on a system
or associated parts of the equipment should be competent according to EN 13313.
People working on refrigerating systems with flammable refrigerants should have know-how of safety aspects of
flammable refrigerant handling, supported by evidence of appropriate training.
Always protect the operating personnel with personal protective equipment appropriate for the tasks to be performed.
Common individual devices are: helmet, goggles, gloves, caps, safety shoes. Additional individual and group protective
equipment should be adopted after an adequate analysis of the specific risks in the area of relevance, according to the
activities to be performed.
Electrical
Never work on any electrical components until the general supply to the unit has been cut using
components
the disconnect switch(es) in the control box. The frequency variators are equipped with capacitor
batteries with a discharge time of 20 minutes; after disconnecting power, wait 20 minutes before
opening the control box.
Refrigerating
Following precautions should be taken before working on the refrigerant circuit:
— Obtain permit for hot work (if required);
system
— Ensure that no flammable materials are stored in the work area and that no ignition sources
are present anywhere in the work area;
— Ensure that suitable fire extinguishing equipment is available;
— Ensure that the work area is properly ventilated before working on the refrigerant circuit or
before welding, brazing or soldering work;
— Ensure that the leak detection equipment being used is non-sparking, adequately sealed or
intrinsically safe;
— Ensure that all maintenance staff have been instructed.
The following procedure should be followed before working on the refrigerant circuit:
The area should be checked with an appropriate refrigerant detector prior to and during any hot
work to make the technician aware of a potentially flammable atmosphere.
If compressors or compressor oils are to be removed, it should be ensured that it has been
evacuated to an acceptable level to ensure that there is no flammable refrigerant remaining within
the lubricant.
Only refrigerant recovery equipment designed for use with flammable refrigerants should
be employed.
If the national rules or regulations permit the refrigerant to be drained, this should be done safely,
using a hose, for example, through which the refrigerant is discharged into the outside
atmosphere in a safe area. It should be ensured that an inflammable explosive refrigerant
concentration cannot occur in the vicinity of an ignition source or penetrate into a building under
any circumstance.
In the case of refrigerating systems with an indirect system, the heat -transfer fluid should be
checked for the possible presence of refrigerant.
After any repair work, the safety devices, for example refrigerant detectors and mechanical
ventilation systems, should be checked and the results recorded.
It should be ensured that any missing or illegible label on components of the refrigerant circuit is
replaced.
Sources of ignition should not be used when searching for a refrigerant leak.
7.1
Routine maintenance
This chiller must be maintained by qualified technicians. Before beginning any work on the system the personnel shall
assure that all security precautions have been taken.
Neglecting unit maintenance, could degrade all parts of the units (coils, compressors, frames, pipes, etc..) with negative
effect on performances and functionality.
There are two different levels of maintenance, which can be chosen according to the type of application (critical/non
critical) or to the installation environment (highly aggressive or not).
Examples of critical applications are process cooling, data centres, etc.
Highly Aggressive Environments can be defined as the follows:
•
Industrial environment (with possible concentration of fumes result of combustion and chemical process)
Table 17– General maintenance table
1.
Remove refrigerant (specify the residual pressure);
2.
Purge circuit with inert gas (e.g. nitrogen);
3.
evacuate to a pressure of 0,3 (abs.) bar (or 0,03 MPa);
4.
Purge again with inert gas (e.g. nitrogen);
5.
Open the circuit
D–EIMAC01905-23_00EN - 43/53
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