Panasonic CU-E18CKR Service Manual page 52

stable, non-flammable refrigerants with low toxicity. / However,
just like R22, the specific gravity of R410A gasis heavier than
that of air. Because of this, it can cause an oxygen deficiency if
it leaks into a closed room since it collects in the lower area of
the room. It also generates toxic gas when it is directly exposed
to a flame, so it must be used ina well ventilated environment
where it will not collect.
Table 1 Physical comparison of R410A and R22
Composition (wt%)
Boiling point (°C)
Vaporizing pressure (25°C)
Saturated vapor density
Flammability
Ozone-destroying point (ODP)
Global-warming point (GWP)
B. Compositional change (pseudo-azeotropic characteristics) /
R410A is a pseudo-azeotropic mixture comprising the two
components R32 and R125. Multi-component refrigerants with
these chemical characteristics exhibit little compositional
changeeven from phase changes due to vaporization 9or
condensation), which means that there is little change in the
circulating refrigerant composition even when the refrigerant
leaks from the gaseous section of the piping. / Accordingly,
R410A can be handledin almost the same manner as the single-
component refrigerant R22. However, when charging, because
there is a slight change in composition between the gas phase
and the liquid phase inside a cylinder or other container,
charging should basically beginwith the liquid side.
C. Pressure characteristics / As seen in Table 2, the gas pressure
of R410A is approximately 1.6 times as high as that of R22 at
the same refrigerant temperature, which means that special
R410A tools and materials with high-pressure
specificationsmust be used for all refrigerant piping work and
servicing.
Table 2 Comparison of R410A and R22 saturated vapor density / Unit: MPa
R410A
R32/R125 (50/50)
-51.4
1.56 Mpa (15.9 kgf/cm
64.0 kg/m
3
Non-flammable
0
1730
R22 (100)
-40.8
) 0.94 Mpa (9.6 kgf/cm
2
44.4 kg/m
Non-flammable
0.005
R22
)
2
3
1700