O96 SPECIFIC FREON REGULATIONS
(1) Outline
The Freon which is used for the refrigeration system and heat insulation of refrigerators is incombustible and
harmless to men directly, and has many outstanding features and has contributed to the development of civilization
as one of important useful substances. Nevertheless, as it has been revealed that some of them (specific Freon)
which was used for cleaning agent, blowing agent and refrigerators deplete the ozone layer, and it has been
decided to discontinue production of Freon till the end of 1995 and to use other substances less affecting the ozone
layer in place of Freon in the worldwide scale.
SHARP Corporation has decided to disuse Freon, use of which is regulated by the Montreal Protocol, and to use
the alternative Freon HFC-134a as a refrigerant and the nonfreon heat insulator as a heat insulation.
(2) Features of HFC-134a cycle and cautions
1. Cautions when changing the refrigerant (from CFC-12 to HFC-134a)
1) Use of any refrigerant and cleaning agent, containing chlorine, is absolutely prohibited.
2) Since the dryer for CFC-12 cannot be used, only the dryer for HFC-134a is used.
Because the refrigerant has smaller molecules, different desiccant is needed.
3) The gas leakage sensors (for CFC-12 and HFC-22) which are used at present cannot be used.
(The former leakage sensors are designed to detect the chlorine contained in Freon. But HFC-134a does
not contain the chlorine.)
4) The repair tools should be for the use of HFC-134a only.
The rubber-based material (sealing material) which is used for the tools at present expands and its tension
reduces. Therefore the specified tools must be used (the rubber-based material has been modified).
2. Change of compressor oil
Change from naphtene-based mineral oil or a-olefin-based synthetic oil to ester-based oil.
1) The compressor and dryer need vacuum evacuation within 15 minutes after the cap is opened.
The quantity of saturated water in the ester-based oil is 200 ppm, namely 40 times higher than that of
conventional oils.
(Since the ester-based oil reacts with water, forming acids. These acids react with the metals, forming metal
salts which cause clogging of capillary tube. Therefore the time must be strictly controlled after the plugs of
compressor and dryer are opened.)
2) The tools only for HFC-134a cycle must be used. The new materials and parts must be cleaned.
The solubility of ester-based oil for HFC-134a and the conventional oils (compressor oil for CFC-12,
anticorrosive oil for couplers and pressure gauges) is extremely low (10 to 20 ppm) . If a small quantity of
conventional oil enters into the cycle, the capillary tube outlet may be clogged. Therefore the use of the tools
which are used at present (for R-12, R-22, R502) must be absolutely prohibited, and the new tools only for
HFC-134a must be used instead.(All the tools which may cause entry of the conventional oil into the cycle)
(such as refrigerant containers, charging cylinders, couplers, pressure gauges, hoses, valves, gauge manifolds,
vacuum pumps, pipe cutters, etc.) and the new tools must be cleaned with ethyl alcohol. Even when several
mg of oil enters into the cycle, the performance is degraded.
3) The use of flux for welding is prohibited.
Although, in principle, there is no weld joint of iron pipes and copper pipes, the flux dissolved in the water
may cause the entry of water into the cycle. Therefore it is forbidden to use the welding flux.
The use of flux for welding for the models SJ-24F,SJ-42F,SJ-45F,SJ-48F type.
Flux shall be melted with pure water so as not to enter the chlorine (in the water supply) into the
system.And flux shall not be into the system.
3. Vacuum level (improvement of vacuum level)
1) The work is executed according to the vacuum evacuation and gas charge procedure shown in the attached
document.
The air in the cycle, especially the oxygen, causes oxidation of ester-based oil. The oxidized oil reacts with
the metal, forming the metal salt which causes clogging of capillary tube. Therefore high vacuum level is
required.
4. Execution of nitrogen replacement in case of brazing
1) Since the oxide scale in the piping which is formed as a result of brazing causes clogging of capillary tube,
the nitrogen replacement of piping is required when welding is performed.
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ACEC
SHARP
