EN
with oxygen-free nitrogen to render the appliance safe for flammable refrigerants. This
process may need to be repeated several times. Compressed air or oxygen shall not be used
for purging refrigerant systems.
For appliances containing flammable refrigerants, other than A2L refrigerants, refrigerants
purging shall be achieved by breaking the vacuum in the system with oxygen-free nitrogen
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 oxygen-free nitrogen 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 potential ignition sources
and that ventilation is available.
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 6inimize the amount of
refrigerant contained in them.
•Cylinders shall be kept in an appropriate position according to the instructions.
•Ensure that the refrigerating 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 refrigerating system.
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.
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 recovered 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 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 refrigerating system unless it
has been cleaned and checked.
