Midea MOAB30-09HFN8-QRD0GW Service Manual Download Page 10

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Safety Precautions

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• The refrigerant charge shall be recovered into the

correct recovery cylinders. The system shall be flushed
with OFN to render the unit safe. This process may
need to be repeated several times. Compressed air or
oxygen shall not be used for this task. Flushing shall
be achieved by breaking the vacuum in the system
with 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 pipe-work are to take place.

• Ensure that the outlet for the vacuum pump is not

close to any ignition sources and there is ventilation
available.

2.16 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.

2.17 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.

• Become familiar with the equipment and its operation.
• Isolate system electrically.

• 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.

• Pump down refrigerant system, if possible.
• If a vacuum is not possible, make a manifold so that

refrigerant can be removed from various parts of the
system.

• Make sure that cylinder is situated on the scales before

recovery takes place.

• Start the recovery machine and operate in accordance

with manufacturer’s instructions.

• Do not overfill cylinders. (No more than 80 % volume

liquid charge).

• Do not exceed the maximum working pressure of the

cylinder, even temporarily.

• 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.

• Recovered refrigerant shall not be charged into

another refrigeration system unless it has been cleaned
and checked.

2.18 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.

2.19 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 the correct numbers of
cylinders for holding the total system charge are
available. All cylinders to be used are designated
for the recovered refrigerant and labelled for that
refrigerant (i.e. special cylinders for the recovery of
refrigerant). Cylinders shall be complete with pressure
relief valve and associated shut-off valves in good
working order.