Table of Contents
Advertisement
4. PIPE INSTALLATION
Be more careful that foreign matter (oil, water, etc.) does not enter the piping than with
refrigerant R410A models. Also, when storing the piping, securely seal the openings by
pinching, taping, etc.
While welding the pipes, be sure to blow dry nitrogen gas through them.
4.1. Selecting the pipe material
Do not use existing pipes from another refrigeration system or refrigerant.
Use pipes that have clean external and internal sides without any contamination which
may cause trouble during use, such as sulfur, oxide, dust, cutting waste, oil, or water.
It is necessary to use seamless copper pipes.
Material: Phosphor deoxidized seamless copper pipes
It is desirable that the amount of residual oil is less than 0.004 oz./100 ft. (40 mg/10 m).
Do not use copper pipes that have a collapsed, deformed, or discolored portion (es-
pecially on the interior surface). Otherwise, the expansion valve or capillary tube may
become blocked with contaminants.
Improper pipe selection will degrade performance. As an air conditioner using R410A
incurs pressure higher than when using conventional (R22) refrigerant, it is necessary to
choose adequate materials.
• Thicknesses of copper pipes used with R410A are as shown in the table.
• Never use copper pipes thinner than those indicated in the table even if they are avail-
able on the market.
Thicknesses of Annealed Copper Pipes (R410A)
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)
7/8 (22.22)
4.2. Pipe requirement
Refer to the Installation Manual of the outdoor unit for description of the length of con-
necting pipe or for difference of its elevation.
• Use pipe with water-resistant heat insulation.
Install heat insulation around both the gas and liquid pipes. Failure to do so may cause
water leaks.
Use heat insulation with heat resistance above 248 °F (120 °C). (Reverse cycle model
only) In addition, if the humidity level at the installation location of the refrigerant piping
is expected to exceed 70 %, install heat insulation around the refrigerant piping. If the
expected humidity level is 70 to 80 %, use heat insulation that is 9/16 in (15 mm)
or thicker and if the expected humidity exceeds 80 %, use heat insulation that is 13/16
in (20 mm) or thicker. If heat insulation is used that is not as thick as specified, conden-
sation may form on the surface of the insulation. In addition, use heat insulation with
heat conductivity of 0.045 W/(m·K) or less (at 68 °F (20 °C)).
4.3. Flare connection (pipe connection) (ARUH72)
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 respectively)
onto the pipe and perform the flare processing with a flare tool. Use the outdoor units
(or RB unit) 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
En-5
CAUTION
CAUTION
Thickness [in (mm)]
Material
0.032 (0.80)
0.032 (0.80)
COPPER
0.032 (0.80)
JIS H3300 C1220T-O
or equivalent
0.039 (1.00)
0.047 (1.20)
COPPER
0.039 (1.00)
JIS H3300 C1220T-H
or equivalent
CAUTION
CAUTION
WARNING
Check if [L] is flared uniformly and
is not cracked or scratched.
Dimension A [in (mm)]
Pipe outside diameter
Flare tool for R410A,
[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
[in (mm)]
flats
1/4 (6.35)
3/8 (9.52)
1/2 (12.70)
5/8 (15.88)
3/4 (19.05)
4.3.2. Bending pipes
• If pipes are shaped by hand, be careful not to collapse them.
• Do not bend the pipes in an angle more than 90°.
• When pipes are repeatedly bent 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
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.)
CAUTION
Hold the torque wrench at its grip, keep-
ing 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.
5/8 (15.88) dia.
3/4 (19.05) dia.
4.4. Brazing connection (pipe connection) (ARUH96)
4.4.1. 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.
4.4.2. Pipe connection
• The gas and liquid pipes connections must be brazed.
• Be sure to braze them before performing any wiring work or installing the drain pipe.
Connection pipe (liquid)
Connection pipe (gas)
Dimension B
[in (mm)]
clutch type
3/8 (9.1)
1/2 (13.2)
0 to 0.020
5/8 (16.6)
(0 to 0.5)
3/4 (19.7)
15/16 (24.0)
Width across flats of Flare
nut [in (mm)]
11/16 (17)
7/8 (22)
1 (26)
1-1/8 (29)
1-7/16 (36)
CAUTION
Tighten with 2
wrenches.
Torque
wrench
Connection pipe
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
Outer diameter of pipe
3/8 in (9.52 mm)
7/8 in (22.22 mm)
0 (0)
-0.015 (-0.4)
Holding
wrench
Flare nut
Advertisement
Table of Contents
