Kaisai KMK-100RY1, Installation Manual

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14 INFORMATION SERVICING
1) Checks to the area
Prior to beginning work on systems containing flammable refrigerants, safety checks are necessary to ensure that the risk of
ignition is minmised. For repair to the refrigerating system, the following precautions shall be complied with prior to conducting
work on the system.
2) Work procedure
Works shall be undertaken under a controlled procedure so as to minimise the risk of a flammable gas or vapour being present
while the work is being performed.
3) General work area
All mintenance staff and others working in the local area shall be instructed on the nature of work being carried out, work in
confined sapces shall be avoided. The area around the work space shall be sectioned off. Ensure that the conditions within the
area have been made safe by control of flammable material.
4) Checking for presence of refrigerant
The area shall be checked with an appropriate refrigerant detector prior to and during work, to ensure the technician is aware
of potentially flammable atmospheres. Ensure that the leak detection equipment being used is suitable for use with flammable
refrigerants, i.e. no sparking, adequately sealed or intrinsically safe.
5) Presence of fire extinguisher
If any hot work is to be conducted on the refrigeration equipment or any associated parts, appropriate fire extinguishing
equipment shall be available to hand. Have a dry power or CO
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fire extinguisher adjacent to the charging area.
6) No ignition sources
No person carrying out work in relation to a refrigeration system which involves exposing any pipe work that contains or has
contained flammable refrigerant shall use any sources of ignition in such a manner that it may lead to the risk of fire or explosion.
All possible ignition sources, including cigarette smoking, should be kept sufficiently far away from the site of installation,
repairing, removing and disposal, during which flammable refrigerant can possibly be released to the surrounding space. Prior
to work taking place, the area around the equipment is to be surveyed to make sure that there are no flammable hazards or
ignition risks. NO SMOKING signs shall be displayed.
7) Ventilated area
Ensure that the area is in the open or that it it adequately ventilated before breaking into the system or conducting any hot work.
A degree of ventilation shall continue during the period that the work is carried out. The ventilation should safely disperse any
released refrigerant and preferably expel it externally into the atmosphere.
8) Checks to the refrigeration equipment
Where electrical components are being changed, they shall be fit for the purpose and to the correct specification. At all times
the manufacturer s maintenance and service guidelines shall be followed. If in doubt consult the manufacturer s technical
department for assistance. The following checks shall be applied to installations using flammable refrigerants:
9) Checks to electrical devices
Repair and maintenance to electrical components shall include initial safety checks and component inspection procedures. If a
fault exists that could compromise safety, then no electrical supply shall be connected to the circuit until it is satisfactorily dealt
with. If the fault cannot be corrected immediately but it is necessary to continue operation, and adequate temporary solution
shall be used. This shall be reported to the owner of the equipment so all parties are advised.
Initial safety checks shall include:
The charge size is in accordance with the room size within which the refrigerant containing parts are installed;
The ventilation machinery and outlets are operating adequately and are not obstructed;
If an indirect refrigerating circuit is being used, the secondary circuits shall be checked for the presence of refrigerant;
marking to the equipment continues to be visible and legible.
Marking and signs that are illegible shall be corrected;
Refrigeration pipe or components are installed in a position where they are unlikely to be exposed to any substance which
may corrode refrigerant containing components, unless the components are constructed of materials which are inherently
resistant to being corroded or are suitably protected against being so corroded.
That capacitors are discharged: this shall be done in a safe manner to avoid possibility of sparking;
That there no live electrical components and wiring are exposed while charging, recovering or purging the system;
That there is continuity of earth bonding.
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a) During repairs to sealed components, all electrical supplies shall be disconnected from the equipment being worked upon
prior to any removal of sealed covers, etc. If it is absolutely necessary to have an electrical supply to equipment during servicing,
then a permanently operating form of leak detection shall be located at the most critical point to warn of a potentially hazardous
situation.
b) Particular attention shall be paid to the following to ensure that by working on electrical components, the casing is not altered
in such a way that the level of protection is affected. This shall include damage to cables, excessive number of connections,
terminals not made to original specification, damage to seals, incorrect fitting of glands, etc.
10) Repairs to sealed components
Ensure that apparatus is mounted securely.
Ensure that seals or sealing materials have not degraded such that they no longer serve the purpose of preventing the
ingress of flammable atmospheres. Replacement parts shall be in accordance with the manufacturer s specifications.
11) Repair to intrinsically safe components
Do not apply any permanent inductive or capacitance loads to the circuit without ensuring that this will not exceed the
permissible voltage and current permitted for the equipment in use. Intrinscially safe components are the only types that can be
worked on while live in the presence of a flammable atmosphere. The test apparatus shall be at the correct rating. Replace
components only with parts specified by the manufacturer. Other parts may result in the ignition of refrigerant in the atmosphere
from a leak.
12) 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.
13) 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.
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.
Ensure that the outlet for the vacuum pump is not closed to any ignition sources and there is ventilation available.
16) Charging procedures
In addition to conventional charging procedures, the following requirements shall be followed:
14) 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. 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 or extinguished. If a leakage of refrigernat 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.
15) Removal and evacuation
When breaking into the refrigerant circuit to make repairs of 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 use of silicon sealant may inhibit the effectiveness of some types of leak detection equipment. Instrinsically safe
components do not have to be isolated prior to working on them.
NOTE
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