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5. PIPE INSTALLATION-1
5.1. Opening a knock out hole
CAUTION
Be careful not to deform or scratch the panel while opening the knock out holes.
To protect the piping insulation after opening a knock out hole, remove any burrs from
the edge of the hole. It is recommended to apply rust prevention paint to the edge of the
hole.
•
Pipes can be connected from 4 directions, front, lateral side, rear side and bottom.
(Fig. A)
•
When connecting at the bottom, remove the service panel and piping cover on the
front of the outdoor unit, and open the knock out hole provided at the bottom corner of
the piping outlet.
•
It can be installed as shown on “Fig. B” cutting out the 2 slits as indicated on “Fig. C”.
(When cutting slits, use a steel saw.)
Fig. A
Service panel
Front
connection
Bottom
connection
(No. 1)
Lateral
connection
Rear
connection
Fig. B
Fig. C
Slit
Slit
Bottom
connection
(No. 2)
5.2. Brazing
CAUTION
If air or another type of refrigerant enters the refrigeration cycle, the internal pressure in
the refrigeration cycle will become abnormally high and prevent the unit from exerting its
full performance.
Apply nitrogen gas while brazing the pipes. If a pipe is brazed without applying nitrogen
gas, an oxidation film will be created.
This can degrade performance or damage the
parts in the unit (such as the compressor or
valves).
Pressure regulating valve
Cap
Brazing area
Nitrogen gas
Nitrogen gas pressure: 0.02 MPa
(= pressure felt sufficiently on
the back of the hand)
For brazing material, use phosphor copper that does not require flux. Do not use flux to
braze pipes. If the flux is the chlorine type, it will cause the pipes to corrode.
Furthermore, if the flux contains fluoride, it will adversely affect the refrigerant pipe
system such as by degrading the refrigerant.
If fluoride is contained, quality of refrigerant deteriorates and affects the refrigerant
piping system.
5.3. Flare connection (pipe connection)
CAUTION
Do not use mineral oil on a flared part. Prevent mineral oil from getting into the system
as this would reduce the lifetime of the units.
While brazing the pipes, be sure to blow dry nitrogen gas through them.
The maximum lengths of this product are shown in the table. If the units are further apart
than this, correct operation cannot be guaranteed.
5.3.1. Flaring
Use special pipe cutter and 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 the 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 respectively) onto the pipe and perform the flare processing with a 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.
Check if [L] is flared uniformly
and is not cracked or scratched.
B
L
Pipe
A
Die
Pipe outside diameter
[in. (mm)]
Dimension A [in. (mm)]
Dimension B [in. (mm)]
Flare tool for R410A,
clutch type
1/4 (6.35)
0 to 0.020
(0 to 0.5)
3/8 (9.1)
3/8 (9.52)
1/2 (13.2)
1/2 (12.70)
5/8 (16.6)
5/8 (15.88)
3/4 (19.7)
3/4 (19.05)
15/16 (24.0)
When using conventional 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.
Width across
flats
Width across
flats
Pipe outside
diameter [in. (mm)]
Width across flats of
Flare nut [in. (mm)]
1/4 (6.35)
11/16 (17)
3/8 (9.52)
7/8 (22)
1/2 (12.70)
1 (26)
5/8 (15.88)
1-1/8 (29)
3/4 (19.05)
1-7/16 (36)
5.3.2. Bending pipes
CAUTION
To prevent breaking of the pipe, avoid sharp bends. Bend the pipe with a radius of
curvature of 3-15/16in. (100mm) to 5-14/16in. (150mm).
If the pipe is bent repeatedly at the same place, it will break.
•
If pipes are shaped by hand, be careful not to collapse them.
•
Do not bend the pipes at an angle of more than 90°.
• When pipes are repeatedly bent or stretched, the material will harden, making it difficult
to bend or stretch them any more.
•
Do not bend or stretch the pipes more than three times.
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