Midea MAD22C3WMT Passeport Technique page 10

(optional for A2L). When the final oxygen-free nitrogen charge is used, the system shall be vented
down to atmospheric pressure to enable work to take place. Ensure that the outlet for the vacuum
pump is not close to any potential ignition sources and that ventilation is available.
12.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 in an appropriate position according to the instructions. 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.
13.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 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.
14.Labelling
Equipment shall be labelled stating that it has been de-commissioned and emptied of refrigerant. The
label shall be dated and signed.
Ensure that there are labels on the equipment stating the equipment contains flammable refrigerant.
15.Recovery
When removing refrigerant from a system, either for servicing or decommissioning, it is
recommended good practice that all refrigerants are removed safely. When transferring refrigerant
into cylinders, ensure that only appropriate refrigerant recovery cylinders are employed. Ensure that
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