Haier 1U71S2SG1FA Service Manual page 60

Cabling
- Check that cabling will not be subject to wear, corrosion, excessive pressure, vibration, sharp edges or any other
adverse environmental effects. The check shall also take into account the effects of aging or continual vibration
from sources such as compressors or fans.
Detection of Flammable Refrigerants Removal and Evacuation
- The refrigerant charge shall be recovered into the correct recovery cylinders and 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.
- 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.
- The vacuum pump is not close to any ignition sources and that ventilation is available.
Charging Procedures
- 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 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 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.
- 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.
- Electrical power must be 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.
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