Indoor/Outdoor Unit Connection Finishing And Test Run; Flaring Work; Pipe Connection - Mitsubishi Electric MS-GA60VB Series Installation Manual

Be sure to fi x the indoor/outdoor unit
connecting wire A and power supply
cord K using this cord clamp.
K
A
Be sure to attach the service panel of the outdoor unit securely. If it is not attached
correctly, it could result in a fi re or an electric shock due to dust, water, etc.
6. INDOOR/OUTDOOR UNIT CONNECTION
FINISHING AND TEST RUN
INSTALLATION INFORMATION FOR THE AIR
CONDITIONER WITH R410A REFRIGERANT
•
This room air conditioner adopts an HFC refrigerant (R410A) which will never destroy
the ozone layer.
•
Pay particular attention to the following points, though the basic installation
procedure is same as that for R22 air conditioners.
1 As R410A has a working pressure approx. 1.6 times as high as that of R22, some
special tools and piping parts / materials are required. (Refer to the table below.)
2 Take suffi cient care not to allow water and other contaminations to enter the
R410A refrigerant during storage and installation, since it is more susceptible to
contaminations than R22.
3 For refrigerant piping, use clean, pressure-proof parts / materials specifi cally
designed for R410A. (Refer to 2. Refrigerant piping.)
4 Composition change may occur in R410A since it is a mixed refrigerant. When
charging, charge liquid refrigerant to prevent composition change.
6-1 Tools dedicated for the air conditioner with R410A
refrigerant
The following tools are required for R410A refrigerant. Some R22 tools can be
substituted for R410A tools.
The diameter of the service port on the stop valve in outdoor unit has been changed to
prevent any other refrigerant being charged into the unit. (Cap size has been changed
from 7/16 UNF with 20 threads to 1/2 UNF with 20 threads.)
Can R22 tools
R410A tools
be used?
Gauge manifold No
Charge hose No
Gas leak detector No
Yes
Torque wrench
No
Flare tool Yes
Flare gauge New
Vacuum pump
New
adaptor
Electronic scale
for refrigerant New
charging
No: Not substitutable for R410A Yes: Substitutable for R410A
Be sure to put the left
portion into the square
hole of the service panel.
Service panel
Fixing screws
Remove the fi xing
screw to open the
Valve cover
service panel.
WARNING
Description
R410A has high pressures beyond the
measurement range of existing gauges. Port
diameters have been changed to prevent any
other refrigerant from being charged into the
unit.
Hose material and cap size have been changed
to improve the pressure resistance.
Dedicated for HFC refrigerant.
1/4
1/2 and 5/8
Clamp bar hole has been enlarged to reinforce
the spring strength in the tool.
Provided for fl aring work (to be used with R22
fl are tool).
Provided to prevent the back fl ow of oil. This
adapter enables you to use existing vacuum
pumps.
It is diffi cult to measure R410A with a charging
cylinder because the refrigerant bubbles due to
high pressure and high-speed vaporization.

6-2 FLARING WORK

•
Main cause of gas leakage is defect in fl aring work.
Carry out correct fl aring work in the following procedure.
1 Pipe cutting
• Cut the copper pipe correctly with pipe cutter.
Copper pipe
2 Burrs removal
• Completely remove all burrs from the cut cross section of pipe.
• Put the end of the copper pipe to downward direction as you remove burrs in order to
avoid to let burrs drop in the piping.
Copper pipe
Burr
3 Putting nut on
• Remove fl are nuts attached to indoor and outdoor
units, then put them on pipe having completed
burr removal.
(not possible to put them on after fl aring work)
• Flare nut for R410A pipe differs from R22 pipe.
Refer to the following table for detail.
mm Inch
ø6.35 1/4
ø9.52 3/8
ø15.88 5/8
4 Flaring work
• Carry out fl aring work using fl aring tool as shown below.
Flaring tool
Clutch type
Wing nut type
Outside diameter
Flare tool for R410A
clutch type
ø6.35 mm 0 to 0.5
ø9.52 mm 0 to 0.5
ø15.88 mm 0 to 0.5
• Firmly hold copper pipe in a die in the dimension shown in the table above.
5 Check
• Compare the fl ared work with fi gure below.
• If fl are is noted to be defective, cut off the fl ared section and do fl aring work again.
Smooth all around
Even length
all around

6-3 PIPE CONNECTION

Note:
Fasten a fl are nut with a torque wrench as specifi ed in the table below.
When fastened too tight, a fl are nut may broken after a long period and cause a leakage
of refrigerant.
1 Indoor unit connection
Connect both liquid and gas pipings to indoor unit.
•
Apply a thin coat of refrigeration oil J on the seat surface of pipe.
•
For connection fi rst align the center, then tighten the fi rst 3 to 4 turns of fl are nut.
•
Use tightening torque table below as a guideline for indoor unit side union joint
section, and tighten using two wrenches. Excessive tightening damages the fl are
section.
No good
Good
Uneven Burred
Tilted
90°
Spare
reamer
Pipe
cutter
Flare nut
Copper pipe
R410A
17
22
29
A
York
Die
Die
Copper pipe
Copper pipe
Flare nut
A (mm)
Conventional fl are tool
Clutch type Wing nut type
1.0 to 1.5 1.5 to 2.0
1.0 to 1.5 1.5 to 2.0
1.0 to 1.5 2.0 to 2.5
Inside is shining without any scratches.
R22
17
22
27