Translation from original instructions
Packaged Rooftop
20
We reserve the right to make changes without any prior notice.
UATYA
4P645202-1
(Annex DD.9) 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 flammability is a consideration.
The following procedure shall be adhered to:
• remove refrigerant;
•
purge the circuit with inert gas (optional for A2L);
•
evacuate (optional for A2L);
• open the circuit by cutting or brazing.
The refrigerant charge shall be recovered into the correct recovery cylinders. For units containing flammable
refrigerants other than A2L 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 purging refrigerant systems.
For units 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.
(Annex DD.10) 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 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.
(Annex DD.11) Decommissioning
Before carrying out this procedure, it is essential that the technician is completely familiar with the unit 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.
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;
•
Label the system when charging is complete (if not already).
•
recovery equipment and cylinders conform to the appropriate standards.
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