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Installation, maintenance, repair, and decommissioning instructions
The refrigerant charge shall be recovered into the correct recovery
cylinders if venting is not allowed by local and national codes for
appliances containing flammable refrigerants. The system shall be purged
with oxygen-free nitrogen to render the appliance safe for flammable
refrigerants. This process might need to be repeated several times.
Compressed air or oxygen shall not be used for purging refrigerant
systems.
For appliances containing flammable refrigerants, refrigerants purging
shall be done by first breaking the vacuum in the system with oxygen-free
nitrogen, and then continuing to fill until the working pressure is achieved.
Then, vent to the atmosphere and finally pull down to a vacuum. This
process shall be repeated until no refrigerant remains in 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.
Ensure that the outlet for the vacuum pump is not close to any potential
ignition sources and that ventilation is available.
Charging procedures
In addition to conventional charging procedures, the following
requirements shall be followed:
a) 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.
b) Cylinders shall be kept in an appropriate position according to the
instructions.
c) Ensure that the refrigerating system is earthed prior to charging
the system with refrigerant.
d) Label the system when charging is complete (if not already).
e) 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 upon completion
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