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4. PIPE INSTALLATION
CAUTION
Be careful that foreign matter (oil, water, etc.) does not enter the piping with refrigerant
R410A models. Also, when storing the piping, securely seal the openings by pinching,
taping, etc.
While brazing the pipes, be sure to purge with dry nitrogen gas.
4.1. Selecting the pipe material
CAUTION
Do not use existing pipes.
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 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 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 available
•
on the market.
Thicknesses of Annealed Copper Pipes (R410A)
Pipe outside diameter [mm (in.)]
Thickness [mm]
6.35 (1/4)
0.80
9.52 (3/8)
0.80
12.70 (1/2)
0.80
15.88 (5/8)
1.00
19.05 (3/4)
1.20
4.2. Pipe requirement
CAUTION
Refer to the Installation Manual of the outdoor unit for description of the length and the
diameter of connecting pipe or for difference of its elevation.
Use pipe with water-resistant heat insulation.
•
CAUTION
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 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 70-80%, use heat insulation that is 15 mm or thicker and if
the expected humidity exceeds 80%, use heat insulation that is 20 mm or thicker. If
heat insulation is used that is not as thick as specifi ed, condensation may form on the
surface of the insulation.
In addition, use heat insulation with heat conductivity of 0.045W/(m·K) or less (at 20 °C).
4.3. Flare connection (pipe connection)
4.3.1. Flaring
Use special pipe cutter and fl are 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 fl are nut (always use the fl are nut attached to the indoor and outdoor units
respectively) onto the pipe and perform the fl are processing with a fl are tool. Leakage
of refrigerant may result if other fl are nuts are used.
(4) Protect the pipes by pinching them or with tape to prevent dust, dirt, or water from
entering the pipes.
B
A
L
Check if [L] is fl ared uniformly
and is not cracked or scratched.
Die
Pipe
Pipe outside diameter
[mm (in.)]
Dimension A [mm]
Dimension B
-
0
0.4
[mm]
Flare tool for R410A,
clutch type
6.35 (1/4)
0 to 0.5
9.1
9.52 (3/8)
13.2
12.70 (1/2)
16.6
15.88 (5/8)
19.7
19.05 (3/4)
24.0
When using conventional fl are tools to fl are R410A pipes, the dimension A should be ap-
proximately 0.5 mm more than indicated in the table (for fl aring with R410A fl are tools) to
achieve the specifi ed fl aring. Use a thickness gauge to measure the dimension A.
Width across
fl ats
Pipe outside diameter
[mm (in.)]
Width across fl ats of
Flare nut [mm]
6.35 (1/4)
17
9.52 (3/8)
22
12.70 (1/2)
26
15.88 (5/8)
29
19.05 (3/4)
36
4.3.2 Bending pipes
If pipes are shaped by hand, be careful not to collapse them.
•
Do not bend the pipes at an angle more than 90°.
•
When pipes are repeatedly bend or stretched, the material will harden, making it diffi cult
•
to bend or stretch them any more.
Do not bend or stretch the pipes more than 3 times.
•
CAUTION
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
CAUTION
Be sure to connect the pipe against the port on the indoor unit and the outdoor unit cor-
rectly. If the centering is improper, the fl are nut cannot tightened smoothly. If the fl are nut
is forced to turn, the threads will be damaged.
Do not remove the fl are nut from the indoor unit pipe until immediately before connecting
the connection pipe.
Do not use mineral oil on fl ared part. Prevent mineral oil from getting into the system as
this would reduce the lifetime of the units.
(1) Detach the caps and plugs from the pipes.
(2) Center the pipe against the port on the indoor unit, and then turn the fl are nut by hand.
Connection pipe
(Gas)
Connection pipe
(Liquid)
Indoor unit
(3) When the fl are 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
fl are nut tightening torques.
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8/31/2012 10:43:20 AM
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AMP Air Conditioning
www.ampair.co.uk | [email protected]
