Refrigerant Piping Work - Mitsubishi Electric American Standard NAXSKS18A112A Série Manuel D'installation

4. Refrigerant piping work
D
B
C
Fig. 4-1
A
ø1/2 (12.7)
ø5/8 (15.88)
Fig. 4-2
Copper
pipe
Burr
Flaring tool
Clutch type Wing nut type
Inside is shining
Smooth all around
without any
scratches.
Even length all
around
4
A
Indoor unit
D
Outdoor unit
E
E
Indoor unit
A
Outdoor unit
B
ø1/4 (6.35)
ø3/8 (9.52)
B
Good No good
90°
Tilted Uneven Burred
Copper pipe
Spare reamer
Pipe cutter
A
Copper pipe
Die
Flare nut
Fig. 4-3
4.1. Refrigerant pipe (Fig. 4-1, Fig. 4-2)
► Check that the difference between the heights of the indoor and outdoor
units, the length of refrigerant pipe, and the number of bends in the pipe are
within the limits shown below.
Pipe length
A
Models
(one way)
NAXSKS18A112A Max. 100 ft (30 m)
NAXSKS24A112A
NAXSKS30A112A Max. 100 ft (30 m) Max. 100 ft (30 m)
NAXSKS36A112A
• Height difference limitation is defined regardless of which unit, indoor or outdoor,
is positioned higher.
• Refrigerant adjustment ... If pipe length exceeds 25 ft. (7.5 m), additional refriger-
ant (R410A) charge is required.
(The outdoor unit is charged with refrigerant for pipe length up to 25 ft. (7.5 m).)
Up to 25 ft (7.5 m)
Pipe length
Exceeding 25 ft (7.5 m)
NAXSKS18A112A
Refrigerant to
NAXSKS24A112A
be added
NAXSKS30A112A
NAXSKS36A112A
• Table below shows the specifications of pipes commercially available.
Outside
diameter
Model Pipe
inch (mm)
For liquid 1/4 (6.35) 0.0315 (0.8)
NAXSKS18A112A
For gas 1/2 (12.7) 0.0315 (0.8)
For liquid 3/8 (9.52) 0.0315 (0.8)
NAXSKS24A112A
For gas 5/8 (15.88) 0.0315 (0.8)
For liquid 3/8 (9.52) 0.0315 (0.8)
NAXSKS30A112A
For gas 5/8 (15.88) 0.0315 (0.8)
For liquid 3/8 (9.52) 0.0315 (0.8)
NAXSKS36A112A
For gas 5/8 (15.88) 0.0315 (0.8)
• To prevent condensation, insulate the 2 refrigerant pipes.
• Refrigerant pipe bending radius must be 4 in. (100 mm) or more
Caution:
Be sure to use the insulation of specified thickness (table on the above). Excessive
insulation may cause incorrect installation of the indoor unit, and too little insulation
may cause condensate to form.
• The unit has flared connections on both indoor and outdoor sides.
• Remove the valve cover from the outdoor unit, then connect the pipe.
• Refrigerant pipes are used to connect the indoor and outdoor units.
• Be careful not to crush or over bend the pipe in pipe bending.
4.2. Flaring work (Fig. 4-3)
1) Cut the cooper pipe as straight as possible with a pipe cutter.
2) Remove all burrs from the cut section of pipe, ensuring that precautions are taken
to avoid getting metal shavings into the piping.
3) Remove flare nuts attached to indoor and outdoor units, then put them on pipe.
4) Flaring work. Firmly hold copper pipe in the dimension shown in the table. Select
A inch (mm) from the table according to the tool you use.
5) Check
• Compare the flared work.
• If flare is defective, cut off the section and repeat procedure.
A inch (mm)
Pipe diameter Nut
Clutch
inch (mm) inch (mm)
type tool
for R410A
1/4 (6.35) 1/4 (17)
3/8 (9.52) 3/8 (22)
0 to 0.02
(0 to 0.5)
(1.0 to 1.5)
1/2 (12.7) 1/2 (26)
5/8 (15.88) 5/8 (29)
Height Number of
B C
difference bends (one way)
Max. 50 ft (15 m) Max. 10
Max. 10
No additional charge is required.
Additional charge is required.
(Refer to the table below.)
1.08 oz each 5 ft. (20 g/m)
2.69 oz each 5 ft. (50 g/m)
Min. wall Insulation
Insulation
thickness thickness
inch (mm) inch (mm)
5/16 (8)
5/16 (8)
5/16 (8)
5/16 (8)
foam plas-
5/16 (8)
5/16 (8)
5/16 (8)
5/16 (8)
Tightening torque
Clutch Wing nut
type tool type tool N·m
(kgf·cm)
for R22 for R22
10 to 13
13.7 to 17.7
0.06 to
(140 to 180)
0.08
25 to 30
(1.5 to 2.0)
34.3 to 41.2
0.04 to
(350 to 420)
0.06
36 to 42
49.0 to 56.4
0.08 to
(500 to 575)
0.10
54 to 58
(2.0 to 2.5)
73.5 to 78.4
(750 to 800)
material
Heat
resisting
tic 0.045
specific
gravity
ft·lb