10
7. Connecting refrigerant pipes and drain pipes
7.1. Refrigerant piping work
This piping work must be done in accordance with the installation manuals for both
outdoor unit.
• For constraints on pipe length and allowable difference of elevation, refer to the
outdoor unit manual.
Caution:
• Install the refrigerant piping for the indoor unit in accordance with the fol-
lowing.
7.2. Flaring work
• Main cause of gas leakage is defect in flaring work.
Carry out correct flaring work in the following procedure.
7.2.1. Pipe cutting
[Fig. 7.2.1] (P.3)
• Using a pipe cutter cut the copper tube correctly.
7.2.2. Burrs removal
[Fig. 7.2.2] (P.3)
• Completely remove all burrs from the cut cross section of pipe/tube.
• Put the end of the copper tube/pipe to downward direction as you remove burrs in
order to avoid burrs drop in the tubing.
7.2.3. Putting nut on
[Fig. 7.2.3] (P.3)
• Remove flare nuts attached to indoor and outdoor unit, then put them on pipe/tube
having completed burr removal.
(not possible to put them on after flaring work)
7.2.4. Flaring work
[Fig. 7.2.4] (P.3)
• Carry out flaring work using flaring tool as shown below.
Firmly hold copper tube in a die in the dimension shown in the table at above.
7.2.5. Check
[Fig. 7.2.5] (P.3)
• Compare the flared work with a figure in right side hand.
• If flare is noted to be defective, cut off the flared section and do flaring work again.
7.3. Pipe connection
[Fig. 7.3.1] (P.3)
• Apply a thin coat of refrigeration oil on the seat surface of pipe.
• For connection first align the center, then tighten the first 3 to 4 turns of flare nut.
• Use tightening torque table below as a guideline for indoor unit side union joint
section, and tighten using two wrenches. Excessive tightening damages the flare
section.
Warning:
Be careful of flying flare nut! (Internally pressurized)
Remove the flare nut as follows:
1. Loosen the nut until you hear a hissing noise.
2. Do not remove the nut until the gas has been completely released (i.e., hiss-
ing noise stops).
3. Check that the gas has been completely released, and then remove the nut.
Outdoor unit connection
Connect pipes to stop valve pipe joint of the outdoor unit in the same manner applied
for indoor unit.
• For tightening use a torque wrench or spanner, and use the same tightening
torque applied for indoor unit.
Refrigerant pipe insulation
• After connecting refrigerant piping, insulate the joints (flared joints) with thermal
insulation tubing as shown below.
[Fig. 7.3.2] (P.3)
1. Remove and discard the rubber bung which is inserted in the end of the unit pip-
ing.
2. Flare the end of the site refrigerant piping.
3. Pull out the thermal insulation on the site refrigerant piping and replace the insu-
lation in its original position.
Cautions On Refrigerant Piping
Be sure to use non-oxidative brazing for brazing to ensure that no
foreign matter or moisture enter into the pipe.
Be sure to apply refrigerating machine oil over the flare connec-
tion seating surface and tighten the connection using a double
spanner.
Provide a metal brace to support the refrigerant pipe so that no
load is imparted to the indoor unit end pipe. This metal brace
should be provided 50 cm away from the indoor unit’s flare con-
nection.
a
Copper tubes
b
Good
c
No good
d
Tilted
e
Uneven
f
Burred
a
Burr
b
Copper tube/pipe
c
Spare reamer
d
Pipe cutter
a
Flare nut
b
Copper tube
a
Flaring tool
b
Die
c
Copper tube
d
Flare nut
e
Yoke
Pipe diameter
(mm)
Dimension
A (mm)
B
(mm)
When the tool for R410A is used
Clutch type
6.35
0 - 0.5
9.1
9.52
0 - 0.5
13.2
12.7
0 - 0.5
16.6
15.88
0 - 0.5
19.7
a
Smooth all around
b
Inside is shining without any scratches
c
Even length all around
d
Too much
e
Tilted
f
Scratch on flared plane
g
Cracked
h
Uneven
i
Bad examples
+0
-0.4
Copper pipe O.D.
(mm)
Flare nut O.D.
(mm)
Tightening torque
(N·m)
ø 6.35
17
14 - 18
ø 9.52
22
34 - 42
ø 12.7
26
49 - 61
ø 15.88
29
68 - 82
A
Pipe cover (small) (accessory)
B
Caution:
Pull out the thermal insulation on the refrigerant piping at the site, insert the flare nut
to flare the end, and replace the insulation in its original position.
Take care to ensure that condensation does not form on exposed copper piping.
C
Liquid end of refrigerant piping
D
Gas end of refrigerant piping
E
Site refrigerant piping
F
Main body
G
Pipe cover (large) (accessory)
H
Thermal insulation (field supply)
I
Pull
J
Flare nut
K
Return to original position
L
Ensure that there is no gap here
M
Plate on main body
N
Band (accessory)
O
Ensure that there is no gap here. Place join upwards.
WT08744X01.book 10 ページ ２０１７年９月１１日 月曜日 午前１０時５１分