Midea MP72SQWBA2RCM Owner's Manual page 10

WARNINGS (for using R32 refrigerant only)
Removal and evacuation
When breaking into the refrigerant circuit to make repairs or for any other purpose
conventional procedures shall be used. However, it is important that best practice is
followed since ammability is a consideration. Opening of the refrigeration systems
shall not be done by brazing.
The following procedure shall be adhered to:
Remove refrigerant;
Purge the circuit with inert gas;
Evacuate;
Purge again with inert gas;
Open the circuit by cutting or brazing.
The refrigerant charge shall be recovered into the correct recovery cylinders. The
system shall be ushed 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 ll until the working pressure is achieved, then venting to
atmosphere, and nally pulling down to a vacuum. This process shall be repeated
until no refrigerant is within the system. When the nal 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.
• Charging procedures
In addition to conventional charging procedures, the following requirements shall be
followed. Ensure that contamination of di erent 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 over ll 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.
• 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.
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