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
|
| Conventional hoses |
| R410A hoses | |
Pressure | Working pressure | 3.4 | MPa (35 kgf/cm3) | 5.1 | MPa (52 kgf/cm3) |
resistance | Bursting pressure | 17.2 | MPa (175 kgf/cm3) | 27.4 | MPa (280 kgf/cm3) |
Material |
|
| NBR rubber | HNBR rubber Nylon coating inside | |
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.
Fig. 5 Vacuum pump adaptor
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. 6 Electric gas leak detector for HFC refrigerant |
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