Daikin R410A Technical Manual page 26

Piping Works And Flaring Technique
• Do not use contaminated or damaged copper tubing. If any pipings, evaporator or condenser had
been exposed or had been opened for 15 seconds or more, the system must be vacuumed.
Generally, do not remove plastic, rubber plugs and brass nuts from the valves, fittings, tubings and
coils until it is ready to connect suction or liquid line into valves or fittings.
• If any brazing work is required, ensure that the nitrogen gas is passed through coil and joints while
the brazing work is being done. This will eliminate soot formation on the inside walls of the copper
tubings.
• Cut the pipe stage by stage, advancing the blade
of the pipe cutter slowly. Extra force and deep
cut will cause more distortion on the pipe and
thus extra burr. See Figure I.
• Remove burrs from cut edges of the pipes with
remover as shown in Figure II. This will avoid
unevenness on the flare faces which will cause
gas leak. Hold the pipe on top position and burr
remover at lower position to prevent metal chips
from entering the pipe.
• Insert the flare nuts, mounted on the connection
parts of both the indoor unit and outdoor unit, into
the copper pipes.
• The exact length of pipe protruding from the top
surface of the swaging block is determined by
the flaring tool. Refer Figure III.
• Fix the pipe firmly on the swaging block. Match
the centers of both the swaging block and the
flaring punch, then tighten the flaring punch fully.
Piping Connection To The Units
• Align the center of the piping and tighten the flare
nut sufficiently with fingers. Refer Figure IV.
• Finally, tighten the flare nut with the torque
wrench until the wrench clicks.
• When tightening the flare nut with the torque
wrench, ensure that the tightening direction
follows the arrow indicated on the wrench.
• The refrigerant pipe connection are insulated by
closed cell polyurethane.
Pipe Size, mm/(in)
6.35 (1/4)
9.52 (3/8)
12.70 (1/2)
15.88 (5/8)
19.05 (3/4)
Ø Tube, D
Inch mm Imperial
(Wing-nut Type)
1/4" 6.35 1.3
3/8" 9.52 1.6
1/2" 12.70 1.9
5/8" 15.88 2.2
3/4" 19.05 2.5
Torque, Nm/(ft-lb)
18 (13.3)
42 (31.0)
55 (40.6)
65 (48.0)
78 (57.6)
A (mm)
Rigid
(Clutch Type)
0.7
1.0
1.3
1.7
2.0
Figure I
Cutting copper tube
1/4t
Figure II
Remove burr
Figure III
Copper tube
D
Swaging block
Figure IV
Flare joint
Flared tube
Indoor piping
Torque wrench
Spanner
Flare nut
24