For appliances containing flammable refrigerants, the system must be flushed with OFN to make the unit safe. You
may need to repeat this process several times. Compressed air or oxygen must not be used for purging refrigerant
systems.
For appliances containing flammable refrigerants, flushing must be achieved by breaking the vacuum in the system
with OFN and continuing to fill until the operating pressure is reached, then discharging to the atmosphere and
finally lowering the vacuum. This process must be repeated until there is no more refrigerant in the system. When
the final OFN charge is used, the system must be vented to atmospheric pressure to allow the work to be carried
out. This operation is absolutely essential if you want to carry out brazing operations on the pipes.
Make sure that the vacuum pump outlet is not close to ignition sources and that ventilation is available.
Charging procedures
In addition to conventional charging procedures, the following requirements must be followed.
- Make sure that contamination of different refrigerants does not occur when using charging equipment. Hoses or
lines should be as short as possible to minimize the amount of refrigerant they contain.
- The cylinders must be kept upright.
- Make sure the refrigeration system is grounded before charging the system with refrigerant.
- Label the system when charging is complete (if not already done).
- Be very careful not to overfill the refrigeration system.
Before recharging the system, it must be pressure tested with the appropriate purge gas.
The system must undergo a leak test upon completion of the charge but prior to commissioning. A subsequent leak
test must be carried out before leaving the site.
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