Daikin FXCQ20MVE, Installation Manual

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6 English
• To prevent contamination or moisture from getting
into the piping, take measures such as pinching or
taping the pipings.
Do not mix substance other than the specified refriger-
ant such as air into the refrigeration circuit.
If the refrigerant leaks during the work, ventilate the
room.
• The refrigerant is pre-charged in the outdoor unit.
• When connecting the pipings to the air conditioner, make
sure to use a spanner and a torque wrench as shown in
Fig. 1 .
• For the dimension of flared part and the tightening torque,
refer to the Table 3.
• When making a flare connection, coat the flared inner sur-
face only with ether oil or ester oil.
(Refer to Fig. 2)
Then, turn the flare nut 3 to 4 times with your hand and screw
in the nut.
• Refer to Table 3 for tightening torque.
Table 3
NOTE
The flare nuts used must be those included with the main body.
CAUTION
Over-tightening may damage the flare and cause a refriger-
ant leakage.
Use “ Table 4 ” as a reference if a torque wrench is not available.
Once work is complete, make sure there is no gas leaking. As
the flare nut is tightened with the wrench, the torque will sud-
denly increase.
From that position, tighten the nut to the angle shown on “ Table 4 ”.
• Make absolutely sure to execute heat insulation works on the
pipe-connecting section after checking gas leakage by thor-
oughly studying the following figure and using the attached
heat insulating materials for fitting. (Fasten both ends with
the clamps (accessory).)
(Refer to Fig. 3)
• Wrap the sealing pad (accessory) only around the insulation
for the joints on the gas piping side.
CAUTION
Be sure to insulate any field piping all the way to the piping
connection inside the unit. Any exposed piping may cause
condensation or burns if touched.
CAUTION
CAUTION TO BE TAKEN WHEN BRAZING REFRIGER-
ANT PIPING
Do not use flux when brazing refrigerant piping. Therefore,
use the phosphor copper brazing filler metal (BCuP-2: JIS Z
3264/B-Cu93P-710/795: ISO 3677) which does not require
flux.
(Flux has extremely harmful influence on refrigerant piping
systems. For instance, if the chlorine based flux is used, it will
cause pipe corrosion or, in particular, if the flux contains flu-
orine, it will damage the refrigerant oil.)
• Before brazing local refrigerant piping, nitrogen gas shall be
blown through the piping to expel air from the piping.
If your brazing is done without nitrogen gas blowing, a large
amount of oxide film develops inside the piping, and could
cause system malfunction.
• When brazing the refrigerant piping, only begin brazing after
having carried out nitrogen substitution or while inserting
nitrogen into the refrigerant piping. Once this is done, con-
nect the indoor unit with a flared or a flanged connection.
• Nitrogen should be set to 0.02 MPa with a pressure-reducing
valve if brazing while inserting nitrogen into the piping.
Not recommendable but in case of emergency
You must use a torque wrench but if you are obliged to install
the unit without a torque wrench, you may follow the installa-
tion method mentioned below.
After the work is finished, make sure to check that there
is no gas leak.
When you keep on tightening the flare nut with a spanner,
there is a point where the tightening torque suddenly
increases. From that position, further tighten the flare nut the
angle shown below:
Pipe
gauge
Tightening torque
(N·m)
Flare
dimension A
(mm)
Flare shape

6.4
(1/4”)
15.7 ± 1.5 8.9 ± 0.2

9.5
(3/8”)
36.3 ± 3.6 13.0 ± 0.2

12.7
(1/2”)
54.9 ± 5.4 16.4 ± 0.2

15.9
(5/8”)
68.6 ± 6.8 19.5 ± 0.2
A
45
0
± 2
0
R0.4-0.8
90
0
± 2
0
Coat the flared inner surface only with
ether oil or ester oil.
Fig. 1
Torque wrench
Spanner
Piping union
Flare nut Fig. 2
Insulation for fi tting
(accessory)
Small sealing pad
Insulation for fi tting
(accessory)
(for gas line)
Clamp (×4)
(accessory)
(for liquid line)
Liquid pipe
Fig. 3
(accessory)
Gas pipe
Refrigerant
piping
Part to be
brazed
Taping
Pressure-
reducing
valve
hands valve
Nitrogen
Nitrogen
01_EN_3P258319-5K.fm Page 6 Thursday, October 15, 2015 11:03 AM