Mitsubishi Electric PUHZ-FRP71VHA2R1, Руководство по обслуживанию

Страница: 6 / 90

6
OCH665B
(2) 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(inch)
Outside
diameter (mm)
Thickness (mm)
R410A R22
1/4 6.35 0.8 0.8
3/8 9.52 0.8 0.8
1/2 12.70 0.8 0.8
5/8 15.88 1.0 1.0
3/4 19.05 — 1.0
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 refriger-
ants. Therefore, to enhance airtightness and strength, flare cutting dimension of copper pipe for R410A has been speci-
fied 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
Dimension B
Flare cutting dimensions Flare nut dimensions
Nominal
dimensions
(in)
Outside
diameter (mm)
Dimension A
(
+0
-0.4
)
(mm)
Nominal
dimensions (in) Outside
diameter (mm)
Dimension A (mm)
R410A R22 R410A R22
1/4 6.35 9.1 9.0 1/4 6.35 17.0 17.0
3/8 9.52 13.2 13.0 3/8 9.52 22.0 22.0
1/2 12.70 16.6 16.2 1/2 12.70 26.0 24.0
5/8 15.88 19.7 19.4 5/8 15.88 29.0 27.0
3/4 19.05 — 23.3 3/4 19.05 — 36.0
3
Tools for R410A (The following table shows whether conventional tools can be used or not.)
Tools and materials Use R410A tools
Can R22 tools be
used?
Can R407C tools be used?
Gauge manifold Air purge, refrigerant charge
and operation check Tool exclusive for R410A × ×
Charge hose Tool exclusive for R410A × ×
Gas leak detector Gas leak check Tool for HFC refrigerant ×
○
Refrigerant recovery equipment Refrigerant recovery Tool exclusive for R410A × ×
Refrigerant cylinder Refrigerant charge Tool exclusive for R410A × ×
Applied oil
Apply to flared section
Ester oil, ether oil and alkylbenzene oil
(minimum amount)
×
Ester oil, ether oil: ○
Alkylbenzene oil: minimum
amount
Safety charger
Prevent compressor malfunction
when charging refrigerant by
spraying liquid refrigerant
Tool exclusive for R410A × ×
Charge valve
Prevent gas from blowing out
when detaching charge hose
Tool exclusive for R410A × ×
Vacuum pump Vacuum drying and air purge
Tools for other refrigerants
can be used if equipped with
adapter for reverse flow check
Δ(Usable if equipped
with adapter for
reverse flow)
Δ(Usable if equipped with
adapter for reverse flow)
Flare tool Flaring work of piping
Tools for other refrigerants can be
used by adjusting flaring dimen
-
sion
Δ(Usable by adjusting
flaring dimension)
Δ(Usable by adjusting flar
-
ing dimension)
Bender Bend the pipes Tools for other refrigerants can be used
○ ○
Pipe cutter Cut the pipes Tools for other refrigerants can be used
○ ○
Welder and nitrogen gas
cylinder
Weld the pipes Tools for other refrigerants can be used
○ ○
Refrigerant charging scale Refrigerant charge Tools for other refrigerants can be used
○ ○
Vacuum gauge or thermistor
vacuum gauge and vacuum
valve
Check the degree of vacuum. (Vacuum
valve prevents back flow of oil and re
-
frigerant to thermistor vacuum gauge)
Tools for other refrigerants can be used
○ ○
Charging cylinder Refrigerant charge Tool exclusive for R410A × -
×
: Prepare a new tool. (Use the new tool as the tool exclusive for R410A.)
Δ
: Tools for other refrigerants can be used under certain conditions.
○
: Tools for other refrigerants can be used.