Loading ...
Loading ...
Loading ...
10 11
5. Information on Servicing
Service should only be performed by a qualified technician.
1) Inspect the area
Before working on systems containing flammable refrigerants, it is necessary to ensure that the
risk of ignition is minimized. Comply with the following precautions before working on
or repairing the refrigerating system.
2) Work procedure
Work shall be undertaken under a controlled procedure to minimize the risk of a flammable
gas or vapor being present while the work is being performed.
3) General work area
All maintenance staff and other people working in the local area shall be instructed on the
nature of work being carried out. Work in confined spaces shall be avoided. The area around the
workspace shall be sectioned off. Ensure that the conditions within the area have been made
safe through control of the flammable material.
4) Checking for the presence of refrigerants
The area shall be checked with an appropriate refrigerant detector prior to and during work to
ensure that 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., non-sparking, adequately sealed, or intrinsically safe.
5) Presence of a fire extinguisher
If any hot work is to be conducted on the refrigeration equipment or any associated parts,
appropriate fire extinguishing equipment shall be on hand. Be sure to have a dry powder or CO
2
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 used to contain flammable refrigerant shall use any sources of ignition
in such a manner that may lead to the risk of fire or an explosion. All possible ignition sources
including cigarette smoking should be kept at a sufficient distance from the site of installation,
repair, removal, 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 an open space or that it is adequately ventilated before breaking into the
system or conducting any hot work. There should be a degree of continuous ventilation while
the work is being 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. When in doubt, consult Customer Service for assistance. The following checks shall
be applied to installations using flammable refrigerants:
The charge size is in accordance with the room size within which the parts containing
refrigerants are installed.
The ventilation machinery and outlets should operate adequately and should not obstructed;
ifan indirect refrigerating circuit is being used, the secondary circuit shall be checked for the
presence of refrigerants.
Any marking to the equipment should continue to be visible and legible. Markings and signs that
are illegible shall be corrected.
Refrigeration pipes 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 corroded.
9) Checks to electrical devices
Repair and maintenance to electrical components shall include initial safety checks and Initial
safety checks shall include:
Ensuring that capacitors are discharged: this shall be done in a safe manner to avoid possible
sparking;
Ensuring that no live electrical components and wiring are exposed while charging, recovering,
or purging the system; Ensuring that there is continuity of earth bonding;
7. Repairs to Sealed Components
1) During repairs to sealed components, all electrical supplies shall be disconnected from the unit
being worked on prior to the removal of sealed covers and other parts (if any). If it is necessary
to have an electrical supply connected to the unit 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.
2) Particular attention shall be paid to the following to ensure that when 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 the cables, an excessive number of connections, terminals not made to
the original specification, damage to seals, incorrect fitting of glands, etc.
Ensure that the unit is mounted securely.
Ensure that the seals or sealing materials have not been degraded to a point 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.
NOTE: The use of silicon sealant may inhibit the effectiveness of some types of leak detection
equipment. Intrinsically safe components do not have to be isolated prior to working on them.
8. Repair to Intrinsically Safe Components
Do not apply any permanent inductive or capacitive loads to the circuit without ensuring that this will
not exceed the permissible voltage and current for the unit in use. Intrinsically safe components are
the only types that can be worked on while live and in the presence of a flammable atmosphere. The
test apparatus shall be at the correct rating. Replace the components only with parts specified by the
manufacturer. Other parts may result in the ignition of refrigerant in the atmosphere from a leak.
9. Cabling
Check that the cabling will not be subject to wear, corrosion, excessive pressure, vibration, sharp edges,
or any other adverse environmental effects. The check shall also consider the effects of aging or continual
vibration from sources such as compressors or fans.
10. Detection of Flammable Refrigerants
Under no circumstances shall potential sources of ignition be used in searching for or detecting refrigerant
leaks. A halide torch (or any other detector using a naked flame) shall not be used.
11. 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 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 refrigerant leak is
found (which requires brazing), all refrigerants shall be recovered from the system, or isolated (by means
of shut off valves) in a part of the system that is situated remotely from the leak. Oxygen free nitrogen
(OFN) shall then be purged from the system both before and during the brazing process.
Loading ...
Loading ...
Loading ...