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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).