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
resistance
Working pressure 3.4 MPa (35 kgf/cm ) 5.1 MPa (52 kgf/cm )
Bursting pressure 17.2 MPa (175 kgf/cm ) 27.4 MPa (280 kgf/cm )
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
8. Electronic scale for refrigerant charging
·
Because of the high pressure and fast vaporizing speed of R410A,
the refrigerant cannot be held in a liquid phase inside the charging
cylinder when charging is done using the charging cylinder method,
causing bubbles to form in the measurement scale glass and
making it difficult to see the reading. (Naturally, the conventional
R22 charging cylinder cannot be used because of the differences in
the pressure resistance, scale gradation, connecting port size, etc.)
·
The electronic scale has been strengthened by using a structure in
which the weight detector for the refrigerant cylinder is held by four
supports. It is also equipped with two connection ports, one for R22
(7/16 UNF, 20 threads) and one for R410A (1/2 UNF, 20 threads),
so it can also be used for conventional refrigerant charging.
·
There are two types of electronic scales, one for 10-kg cylinders
and one for 20-kg cylinders. (The 10-kg cylinder is recommended.)
Refrigerant charging is done manually by opening and closing the
valve.
Fig. 7 Electronic scale for refrigerant charging
44
CS-MVG103KE / CU-MVG153KE
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