90
5. Charging hose
• The pressure resistance of the charging hose has been
raised to match the higher pressure of R410A. The hose
material has also been changed to suit HFC use, and the
size of the fitting has been changed to match the
manifold ports.
Fig. 4 Manifold gauge charging hose
Table 8 Difference between R410A and conventional charging hoses
6. Vacuum pump adaptor
• When using a vacuum pump for R410A, it is necessary
to install an electromagnetic valve to prevent the vacuum
pump oil from flowing back into the charging hose. The
vacuum pump adaptor is installed for that purpose. If the
vacuum pump oil (mineral oil) becomes mixed with
R410A, it will damage the unit.
7. Electric gas leak detector for HFC refrigerant
• The leak detector and halide torch that were used with
CFC and HCFC cannot be used with R410A (because
there is no chlorine in the refrigerant).
• The present R134a leak detector can be used, but the
detection sensitivity will be lower (setting the sensitivity
for R134a at 1, the level for R410A will drop to 0.6).
• For detecting small amounts of gas leakage, use the
electric gas leak detector for HFC refrigerant. (Detection
sensitivity with R410A is about 23 g/year).
Fig. 5 Vacuum pump adaptor
Fig. 6 Electric gas leak detector for HFC refrigerant
Conventional hoses R410A hoses
Pressure
resistance
Working pressure
3.4 MPa (35 kgf/cm
3
) 5.1 MPa (52 kgf/cm
3
)
Bursting pressure
17.2 MPa (175 kgf/cm
3
) 27.4 MPa (280 kgf/cm
3
)
Material NBR rubber HNBR rubber Nylon coating inside
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