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When the final OFN charge is used, the system shall be vented down to atmospheric pressure to en-
able 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 closed to any ignition sources and there is ventila-
tion available.
16. 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 minimize 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.
17. Decommissioning
Before carrying out this procedure, it is essential that the technician is completely 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.
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 protetive 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 cylin-
ders 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.
