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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 pipework are to take place.
Ensure that the outlet for the vacuum pump is not close to any ignition sources and there is
ventilation available.
8 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.
9 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 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.
10 LABELLING
Equipment shall be labelled stating that it has been de-commissioned and emptied of refri-
gerant.The label shall be dated and signed.
Ensure that there are labels on the equipment stating the equipment contains flammable
refrigerant.
11 RECOVERY