Mitsubishi Electric PUHZ-P200YHA Service Manual page 5

Cautions for refrigerant piping work
New refrigerant R410A is adopted for replacement inverter series. Although the refrigerant piping work for R410A is same as
for R22, exclusive tools are necessary so as not to mix with different kind of refrigerant. Furthermore as the working pressure
of R410A is 1.6 time higher than that of R22, their sizes of flared sections and flare nuts are different.
1Thickness of pipes
Because the working pressure of R410A is higher compared to R22, be sure to use refrigerant piping with thickness
shown below. (Never use pipes of 0.7mm or below.)
Diagram below: Piping diameter and thickness
Nominal
diameter (mm)
dimensions(inch)
1/4
3/8
1/2
5/8
3/4
2Dimensions of flare cutting and flare nut
The component molecules in HFC refrigerant are smaller compared to conventional refrigerants. In addition to that,
R410A is a refrigerant, which has higher risk of leakage because its working pressure is higher than that of other refriger-
ants. Therefore, to enhance airtightness and intensity, flare cutting dimension of copper pipe for R410A have been speci-
fied separately from the dimensions for other refrigerants as shown below. The dimension B of flare nut for R410A also
have partly been changed to increase intensity as shown below. Set copper pipe correctly referring to copper pipe flaring
dimensions for R410A below. For 1/2 and 5/8 inch, the dimension B changes.
Use torque wrench corresponding to each dimension.
Dimension A
Flare cutting dimensions
Nominal Outside
dimensions(inch) diameter
1/4 6.35
3/8 9.52
1/2 12.70
5/8 15.88
3/4 19.05
3Tools for R410A (The following table shows whether conventional tools can be used or not.)
Tools and materials
Gauge manifold
Charge hose
Gas leak detector
Refrigerant recovery equipment
Refrigerant cylinder
Applied oil
Safety charger
Charge valve
Vacuum pump
Flare tool
Bender
Pipe cutter
Welder and nitrogen gas cylinder
Refrigerant charging scale
Vacuum gauge or thermis-
tor vacuum gauge and
vacuum valve
Charging cylinder
: Prepare a new tool. (Use the new tool as the tool exclusive for R410A.)
: Tools for other refrigerants can be used under certain conditions.
: Tools for other refrigerants can be used.
Thickness (mm)
Outside
R410A
6.35 0.8
9.52 0.8
12.70 0.8
15.88 1.0
—
19.05
(mm)
Dimension A ( +0
-0.4
R410A R22
9.1 9.0
13.2 13.0
16.6 16.2
19.7 19.4
24.0 23.3
Use R410A tools
Air purge, refrigerant charge and
Tool exclusive for R410A
Operation check
Tool exclusive for R410A
Tool for HFC refrigerant
Gas leak check
Refrigerant recovery
Tool exclusive for R410A
Refrigerant charge
Tool exclusive for R410A
Apply to flared section
Ester oil, ether oil and
alkylbenzene oil(minimum amount)
Prevent compressor malfunction Tool exclusive for R410A
when charging refrigerant by
spraying liquid refrigerant
Prevent gas from blowing out Tool exclusive for R410A
when detaching charge hose
Vacuum drying and air Tools for other refrigerants can
purge be used if equipped with adop-
ter for reverse flow check
Flaring work of piping Tools for other refrigerants
can be used by adjusting
flaring dimension
Bend the pipes Tools for other refrigerants can be used
Cut the pipes Tools for other refrigerants can be used
Tools for other refrigerants can be used
Weld the pipes
Charge refrigerant Tools for other refrigerants can be used
Check the degree of vacuum. (Vacuum Tools for other refrigerants
valve prevents back flow of oil and refri-
can be used
gerant to thermistor vacuum gauge)
Refrigerant charge
Tool exclusive for R410A
R22
0.8
0.8
0.8
1.0
1.0
Flare nut dimensions
)
Nominal
dimensions(inch)
1/4
3/8
1/2
5/8
3/4
Can R22 tools be used?
(Usable if equipped
with adopter for rever-
se flow)
(Usable by adjusting
flaring dimension)
5
Dimension B
Dimension B
Outside
diameter R410A
6.35 17.0
9.52 22.0
12.70 26.0
15.88 29.0
19.05 36.0
Can R407C tools be used?
Ester oil, ether oil:
Alkylbenzene oil: minimum amount
(Usable if equipped
with adopter for rever-
se flow)
(Usable by adjusting
flaring dimension)
(mm)
R22
17.0
22.0
24.0
27.0
36.0