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4.3. Flare connection (pipe connection)
Tighten the flare nuts with a torque wrench using the specified tightening method. Oth-
erwise, the flare nuts could break after a prolonged period, causing refrigerant to leak
and generate a hazardous gas if the refrigerant comes into contact with a flame.
4.3.1. Flaring
Use special flare tool exclusive for R410A.
(1) Cut the connection pipe to the necessary length with a pipe cutter.
(2) Hold the pipe downward so that cuttings will not enter the pipe and remove any burrs.
(3) Insert the flare nut (always use the flare nut attached to the indoor and outdoor units
(or RB unit) respectively) onto the pipe and perform the flare processing with a flare
tool. Use the special R410A flare tool. Leakage of refrigerant may result if other flare
nuts are used.
(4) Protect the pipes by pinching them or with tape to prevent dust, dirt, or water from
entering the pipes.
Die
Pipe
Pipe outside diameter
[in (mm)]
1/4 (6.35)
3/8 (9.52)
1/2 (12.70)
5/8 (15.88)
3/4 (19.05)
When using conventional (R22) flare tools to flare R410A pipes, the dimension A should
be approximately 0.020 in (0.5 mm) more than indicated in the table (for flaring with
R410A flare tools) to achieve the specified flaring. Use a thickness gauge to measure the
dimension A. It is recommended that a R410A flaring tool is used.
Pipe outside diameter
Width across
flats
4.3.2. Bending pipes
• The pipes are shaped by your hands or pipe bender. Be careful not to collapse them.
• Do not bend the pipes in an angle more than 90°.
• When pipes are repeatedly bend or stretched, the material will harden, making it difficult
to bend or stretch them anymore. Do not bend or stretch the pipes more than 3 times.
To prevent breaking of the pipe, avoid sharp bends.
If the pipe is bent repeatedly at the same place, it will break.
4.3.3. Pipe connection
Be sure to install the pipe against the port on the indoor unit and the outdoor unit cor-
rectly. If the centering is improper, the flare nut cannot tighten smoothly. If the flare nut is
forced to turn, the threads will be damaged.
Do not remove the flare nut from the indoor unit pipe until immediately before connect-
ing the connection pipe.
Do not use mineral oil on flared part. Prevent mineral oil from getting into the system as
this would reduce the lifetime of the units.
Connect the silencer pipe to the small
(liquid) pipe.
Centering the pipe against port on
the indoor unit, turn the flare nut with
your hand.
Be sure that the small pipe is com-
pletely installed before connecting the
large pipe.
En-5
WARNING
Check if [L] is flared uniformly and
is not cracked or scratched.
Dimension A [in (mm)]
Dimension B
Flare tool for R410A,
clutch type
0 to 0.020 (0 to 0.5)
Width across flats of Flare
[in (mm)]
nut [in (mm)]
1/4 (6.35)
11/16 (17)
3/8 (9.52)
7/8 (22)
1/2 (12.70)
5/8 (15.88)
1-1/8 (29)
3/4 (19.05)
1-7/16 (36)
CAUTION
CAUTION
Indoor unit side
Silencer pipe
(accessories)
If necessary, cut the silencer pipe
and use it.
When the flare nut is tightened
properly by your hand, hold the
body side coupling with a separate
spanner, then tighten with a torque
wrench. (See the table below for the
flare nut tightening torques.)
Hold the torque wrench at its grip,
keeping it at a right angle with the
pipe, in order to tighten the flare
nut correctly.
Flare nut [in (mm)]
1/4 (6.35) dia.
3/8 (9.52) dia.
1/2 (12.70) dia.
0 (0)
5/8 (15.88) dia.
-0.015 (-0.4)
[in (mm)]
3/4 (19.05) dia.
3/8 (9.1)
1/2 (13.2)
4.4. Installing heat insulation
5/8 (16.6)
3/4 (19.7)
15/16 (24.0)
After checking for gas leaks (refer to the Installation Manual of the outdoor unit), per-
form this section.
Install heat insulation around both the large (gas) and small (liquid) pipes. Failure to do
so may cause water leaks.
After checking for gas leaks,
insulate by wrapping insula-
tion around the 2 parts (gas
and liquid) of the indoor unit
coupling, using the coupler
heat insulation.
After installing the coupler
1 (26)
heat insulation, wrap both
ends with vinyl tape so that
there is no gap.
Secure both ends of the
heat insulation material us-
ing Cable tie (large).
And finally fix connection
pipe (liquid) to connection
pipe (gas) by rolling vinyl
tape over coupler heat
insulation (gas) and coupler
heat insulation (liquid).
Silencer pipe
There should be no gaps between the insulation and the unit.
Torque wrench
CAUTION
Indoor unit pipe
(body side)
Tightening torque [lbf·ft (N·m)]
11.8 to 13.3 (16 to 18)
23.6 to 31.0 (32 to 42)
36.1 to 45.0 (49 to 61)
46.5 to 55.3 (63 to 75)
66.4 to 81.1 (90 to 110)
CAUTION
No gap
Coupler heat
insulator
(accessories)
Gas pipe
Small pipe
Insulation (pipe)
(accessories)
CAUTION
Silencer pipe
(accessories)
Tighten with 2
wrenches.
Holding
wrench
Flare nut
Connection pipe
Indoor unit
Cable tie (large)
(accessories)
Coupler heat
insulator (ac-
cessories)
Be sure to
overlap the
insulation
Cable tie (large)
(accessories)
Liquid pipe
No gap
Coupler heat insulation
No gap
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