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.
2. REPAIRS TO SEALED COMPONENTS
1) During repairs to sealed components, all electri-
cal supplies shall be disconnected from the
equipment being worked upon prior to any removal
of sealed covers, etc. If it isabsolutely. 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.
2) Particular attention shall be paid to the follow-
ing to ensure that by working on electrical compo-
nents, 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. 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 flamma-
ble atmospheres. Replacement parts shall be in
accordance with the manufacturer’s specifica-
tions.
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.
3. REPAIR TO INTRINSICALLY SAFE COMPO-
NENTS
Do not apply any permanent inductive or capaci-
tance loads to the circuit without ensuring that this
will not exceed the permissible voltage and current
permitted for the equipment in use. Intrinsically
safe components are the only types that can be
worked on while live in the presence of a flamma-
ble 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.
4. 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.
5. 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.
6. 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 pipe-work. If a leak is suspected, all naked
flames shall be removed/ extinguished. If a leakage
of refrigerant 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.
7. 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 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 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
5
5
EN
Ref. 636134
DEHUMIDIFIER
DESHUMIFICADOR
