LG UU50WR2 Installation Manual page 11

Removal and evacuation (For R32)
When breaking into the refrigerant circuit to make repairs – or for any other purpose –
conventional procedures shall be used. However, for flammable refrigerants 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);
• Purge with inert gas (optional for A2L);
• Open the circuit by cutting or brazing
The refrigerant charge shall be recovered into the correct recovery cylinders. For appliances
containing flammable refrigerants other than A2L refrigerants, the system shall be purged with
oxygen-free nitrogen to render the appliance safe for flammable refrigerants. This process may
need to be repeated several times. Compressed air or oxygen shall not be used for purging
refrigerant systems.
For appliances 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.
Ensure that the outlet for the vacuum pump is not close to any potential ignition sources and that
ventilation is available.
Leak detection methods (For R32)
The following leak detection methods are deemed acceptable for systems containing flammable
refrigerants.
Electronic leak detectors shall be used to detect flammable refrigerants, but the sensitivity may
not be adequate, or may need re-calibration. (Detection equipment shall be calibrated in a
refrigerant-free area.)
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 confirmed.
Leak detection fluids are also 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.
NOTE
Examples of leak detection fluids are
- Bubble method
- Gluorescent method agents
SAFETY INSTRUCTIONS
11