e) If a vacuum is not possible, make a manifold so that refrigerant can be removed from
various parts of the system.
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.
Decommissionin
Charging procedures
g
a) Become familiar with the equipment and its operation.
b) Isolate system electrically.
c) Before attempting the procedure, ensure that:
Before carrying out this procedure, it is essential that the technician is completely
The refrigerant charge shall be recovered into the correct recovery cylinders.
For appliances containing flammable refrigerants, 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 purging refrigerant systems.
Ensure that the outlet for the vacuum pump is not close to any ignition sources and that
ventilation is available.
In addition to conventional charging procedures, the following requirements shall be followed.
Prior to recharging the system, it shall be pressure-tested with the appropriate purging gas.
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.
– 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.
For appliances containing flammable refrigerants, 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.
familiar with 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.
d) Pump down refrigerant system, if possible.
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Ensure that the apparatus is mounted securely.
Ensure that seals or sealing materials have not degraded to the 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.
Cabling
Removal and evacuation
Leak detection methods
NOTE : The use of silicon sealant can inhibit the effectiveness of some types of leak
detection equipment. Intrinsically safe components do not have to be isolated prior to
working on them.
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.
The following leak detection methods are deemed acceptable for all refrigerant systems.
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.
remove refrigerant;
purge the circuit with inert gas;
evacuate;
purge again with inert gas;
open the circuit by cutting or brazing.
If a leakage of refrigerant is found which requires brazing, all of the refrigerant shall be
When breaking into the refrigerant circuit to make repairs – or for any other purpose –
conventional procedures shall be used. However, for flammable refrigerants it is important
that best practice is followed since flammability is a consideration. The following procedure
shall be adhered to:
recovered from the system, or isolated (by means of shut off valves) in a part of the system
remote from the leak. For appliances containing flammable refrigerants, oxygen free
nitrogen (OFN) shall then be purged through the system both before and during the
brazing process
Electronic leak detectors may be used to detect refrigerant leaks but, in the case of
flammable refrigerants, 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.
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