Mitsubishi Electric PUMY-P200YKM2 Technical & Service Manual page 4

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 times higher than that of R22, their sizes of flared sections and flare nuts are different.
1 Thickness 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 0.7 mm or below.)
Diagram below: Piping diameter and thickness
Nominal
dimensions (in)
1/4
3/8
1/2
5/8
3/4
7/8
* Use 1/2 H or H pipes.
2 Dimensions 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 refrig-
erants. Therefore, to enhance airtightness and strength, flare cutting dimension of copper pipe for R410A has been
specified separately from the dimensions for other refrigerants as shown below. The dimension B of flare nut for R410A
also has partly been changed to increase strength as shown below. Set copper pipe correctly referring to copper pipe
flaring dimensions for R410A below. For 1/2 and 5/8 inch pipes, the dimension B changes.
Use torque wrench corresponding to each dimension.
Dimension A
Flare cutting dimensions
Nominal Outside
dimensions (in) diameter (mm)
1/4
6.35
3/8 9.52
1/2 12.70
5/8 15.88
3/4
19.05
3 Tools 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 Weld the pipes
Refrigerant charging scale Refrigerant charge
Vacuum gauge or
thermistor 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.
OCH675D
Outside
diameter (mm)
6.35
9.52
12.70
15.88
19.05
22.2
+0
Dimension A (
-0.4
R410A
9.1
13.2
16.6
19.7
—
R410A tools
Use
Tool exclusive for R410A
Air purge, refrigerant charge
and operation check
Tool exclusive for R410A
Gas leak check
Tool for HFC refrigerant
Tool exclusive for R410A
Refrigerant recovery
Tool exclusive for R410A
Refrigerant charge
Ester oil, ether oil and
Apply to flared section alkylbenzene oil
(minimum amount)
Prevent compressor malfunction
when charging refrigerant by Tool exclusive for R410A
spraying liquid refrigerant
Prevent gas from blowing out
Tool exclusive for R410A
when detaching charge hose
Tools for other refrigerants
Vacuum drying and air
can be used if equipped with
purge
adopter for reverse flow check
Tools for other refrigerants can be
Flaring work of piping
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
Tools for other refrigerants can be used
Check the degree of vacuum. (Vacuum
Tools for other refrigerants
valve prevents back flow of oil and
can be used
refrigerant to thermistor vacuum gauge)
Tool exclusive for R410A
Refrigerant charge
Thickness (mm)
R410A
0.8
0.8
0.8
1.0
1.0*
1.0*
Flare nut dimensions
)(mm) Nominal
R22
dimensions (in)
1/4
9.0
13.0 3/8
16.2 1/2
19.4
5/8
3/4
23.3
Can R22 tools be used? Can R407C tools be used?
(Usable if equipped with
adapter for reverse flow)
(Usable by adjusting
flaring dimension)
4
R22
0.8
0.8
0.8
1.0
1.0
1.0
Dimension B
Outside Dimension B(mm)
R410A
diameter (mm)
6.35 17.0
9.52 22.0
12.70 26.0
15.88 29.0
19.05 —
Ester oil, ether oil:
Alkylbenzene oil: minimum amount
(Usable if equipped with
adapter for reverse flow)
(Usable by adjusting
flaring dimension)
R22
17.0
22.0
24.0
27.0
36.0
─