Toshiba Super Modular Unit MMU-AP0091H Installation Manual page 8

New refrigerant (R-410A)
This air conditioner features a new HFC type refrigerant (R-410A) which does not deplete the ozone layer.
1. Safety caution concerned with new refrigerant
The pressure of R-410A is 1.6 times higher than that of former refrigerant R-22. The refrigerating oil has also
been changed. Therefore be sure that the former refrigerant, refrigerant oil and other contaminants are not mixed
into the refrigerating cycle of the air conditioner with the new refrigerant during installation or service work. If
incorrect work is performed, there is a possibility of serious accident. Use tools and materials exclusive to R-
410A.
2. Cautions on installation/service
• Do not mix other refrigerants or other refrigeration oil with R-410A
• The types of tools and joints, including the service port differ from those of the former refrigerant in order to
prevent mistakes.
• The operational pressure of R-410A is high, always use pipes with the correct wall thickness and which are
specified for R-410A.
• During installation, ensure pipes are clean and ensure contaminants do not enter the pipes as the system is
affected by impurities such as water, oxide scales, dirt, oil, etc.
• Ensure brazing is completed using .owing OFN (Oxygen Free Nitrogen) gas.
• Use a vacuum pump for air purge, not refrigerant.
• R-410A refrigerant is an azeotropic mixture type refrigerant. Therefore use liquid to charge the refrigerant. If gas
is used, the composition of refrigerant will change which affects the performance characteristics of the air
conditioner.
3. Materials
• For the refrigerant pipes, use copper pipes and keep the number of joints to a minimum.
• When using long copper pipe for R-410A, it is recommended to use seamless copper material which includes
bonded oil, of amount 40 mg/10 ml or less.
• Do not use crushed, deformed or discoloured pipes.
• Use material in which the amount of contaminates inside the pipe or joint are kept to an absolute minimum.
• The use of flared joints for joining refrigeration pipes should not be used, except where fitted to the indoor/
outdoor units by the factory.
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