Ref. 07688
INSTRUCCIONES IMPORTANTES DE SEGURIDAD
INSTRUÇÕES IMPORTANTES DE SEGURANÇA / IMPORTANT SAFETY INSTRUCTIONS
rer’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
.
3. 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.
Intrinsically 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.
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. Com-
pressed 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
