Panasonic Inverter R32 Series Technical Data & Service Manual page 120

• Ensure that the detector is not a potential source of ignition and is suitable for the refrigerant used.
• Leak detection equipment shall be set at a percentage of the LFL of the refrigerant and shall be calibrated
to the refrigerant employed, and the appropriate percentage of gas (25 % maximum) is confi rmed.
• Leak detection fl uids are suitable for use with most refrigerants but the use of detergents containing
chlorine shall be avoided as the chlorine may react with the refrigerant and corrode the copper pipe-work.
• If a leak is suspected, all naked fl ames shall be removed/extinguished.
• If a leakage of refrigerant is found which requires brazing, all of the refrigerant shall be recovered from the
system, or isolated (by means of shut off valves) in a part of the system remote from the leak.
For appliances containing fl ammable refrigerants, oxygen free nitrogen (OFN) shall then be purged through
the system both before and during the brazing process.
8. 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 fl ammability is a consideration. 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 "fl 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 purging refrigerant systems.
• Flushing shall be achieved by breaking the vacuum in the system with OFN and continuing to fi ll
until the working pressure is achieved, then venting to atmosphere, and fi nally pulling down to a
vacuum.
• This process shall be repeated until no refrigerant is within the system.
• When the fi 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 that ventilation
is available.
9. 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 over fi ll the refrigeration system.
• Prior to recharging the system it shall be pressure tested with OFN (refer to " 7. Leak detection
methods " on page 1-11-18).
• 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.
• Electrostatic charge may accumulate and create a hazardous condition when charging and
discharging the refrigerant.
To avoid fi re or explosion, dissipate static electricity during transfer by grounding and bonding
containers and equipment before charging/discharging.
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