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A. IMPORTANT SAFETY AND GENERAL INFORMATION
corroded or are suitably protected against being so corroded.
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, an 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:
a. That capacitors are discharged: this shall be done in a safe manner
to avoid possibility of sparking;
b. That there no live electrical components and wiring are exposed
while charging, recovering or purging the system;
c. That there is continuity of earth bonding.
7. 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.
8. 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.
9. 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.
10. 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.
11. 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
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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 close to any ignition sources and there is
ventilation available.
12. Charging procedures:
In addition to conventional charging procedures, the following
requirements shall be followed. Ensure that contamination of different
refrigerants does not occur when using charging equipment. Hoses
or lines shall be as short as possible to minimise the amount of
refrigerant contained in them. Cylinders shall be kept upright. Ensure
that the refrigeration system is earthed prior to charging the system
with refrigerant. Label the system when charging is complete (if not
already). Extreme care shall be taken not to overfill the refrigeration
system. Prior to recharging the system it shall be pressure tested
with OFN. The system shall be leak tested on completion of charging
but prior to commissioning. A follow up leak test shall be carried out
prior to leaving the site.
13. Decommissioning:
Before carrying out this procedure, it is essential that the technician
is completely familiarwith the equipment and all its detail. It is
recommended good practice that all refrigerants are recovered safely.
Prior to the task being carried out, an oil and refrigerant sample shall
be taken in case analysis is required prior to re-use of reclaimed
refrigerant. It is essential that electrical power is available before the
task is commenced.
a. Become familiar with the equipment and its operation.
b. Isolate system electrically.
c. Before attempting the procedure ensure that: Mechanical handling
equipment is available, if required, for handling refrigerant cylinders;
All personal protective equipment is available and being used
correctly; The recovery process is supervised at all times by a
competent person; Recovery equipment and cylinders conform to the
appropriate standards.
d. Pump down refrigerant system, if possible.
e. If a vacuum is not possible, make a manifold so that refrigerant can
be removed from various parts of the system.
f. Make sure that cylinder is situated on the scales before recovery
takes place.
g. Start the recovery machine and operate in accordance with
manufacturer's instructions.
h. Do not overfill cylinders. (No more than 80 % volume liquid charge).
i. Do not exceed the maximum working pressure of the cylinder, even
temporarily.
j. When the cylinders have been filled correctly and the process
completed, make sure that the cylinders and the equipment are
removed from site promptly and all isolation valves on the equipment
are closed off.
k. Recovered refrigerant shall not be charged into another
refrigeration system unless it has been cleaned and checked.
14. Labeling:
Equipment shall be labelled stating that it has been de-commissioned
and emptied of refrigerant. The label shall be dated and signed.
Ensure that there are labels on the equipment stating the equipment
contains flammable refrigerant.
15. Recovery:
When removing refrigerant from a system, either for servicing
or decommissioning, it is recommended good practice that all
refrigerants are removed safely. When transferring refrigerant
into cylinders, ensure that only appropriate refrigerant recovery
cylinders are employed. Ensure that the correct number of cylinders
A. IMPORTANT SAFETY AND GENERAL INFORMATION
for holding the total system charge is available. All cylinders to be
used are designated for the recovered refrigerant and labeled for that
refrigerant (i.e. special cylinders for the recovery of refrigerant).
Cylinders shall be complete with pressure relief valve and associated
shut-off valves in good working order. Empty recovery cylinders
are evacuated and, if possible, cooled before recovery occurs. The
recovery equipment shall be in good working order with a set of
instructions concerning the equipment that is at hand and shall be
suitable for the recovery of flammable refrigerants. In addition, a set
of calibrated weighing scales shall be available and in good working
order. Hoses shall be complete with leak-free disconnect couplings
and in good condition. Before using the recovery machine, check
that it is in satisfactory working order, has been properly maintained
and that any associated electrical components are sealed to prevent
ignition in the event of a refrigerant release. Consult manufacturer
if in doubt. The recovered refrigerant shall be returned to the
refrigerant supplier in the correct recovery cylinder, and the relevant
Waste Transfer Note arranged. Do not mix refrigerants in recovery
units and especially not in cylinders. If compressors or compressor
oils are to be removed, ensure that they have been evacuated to an
acceptable level to make certain that flammable refrigerant does not
remain within the lubricant. The evacuation process shall be carried
out prior to returning the compressor to the suppliers. Only electric
heating to the compressor body shall be employed to accelerate this
process. When oil is drained from a system, it shall be carried out
safely.
NOTE: Check the appliance regularly and refer to TROUBLESHOOTING
or contact our customer support if it shows any of the following signs:
- Power cord or plug is damaged.
- Loud noise, unusual smell or excessive heat.
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