8
Ducted Air Conditioners
Installation Manual
•
Be sure to use both a spanner and torque wrench together, as shown in the diagram, when connecting or
disconnecting pipes to/from the unit. (Fig. 7)
•
Use only a flaring block suitable for R410A tube. Refer to Table 2 for the specifications of the flare work.
•
When connecting the flare nut, coat the flare both inside and outside with ether oil and initially tighten
by hand 3 or 4 turns before tightening firmly. (Fig. 8)
•
Use the flare nuts included with the indoor unit.
•
Refer to Table 2 to determine the proper tightening torque.
CAUTION
•
Over tightening the flare nuts may cause the flare nuts or copper tube to fail and allow the refrigerant to leak.
• Caution to be taken when brazing refrigerant piping. (Where applicable).
Do not use flux when brazing refrigerant piping. Use the phosphor copper brazing filler metal (BCuP)
which does not require flux. (Flux has an extremely harmful influence refrigerant piping systems. For
instance, if chlorine based flux is used, it will cause pipe corrosion, particularly if the flux contains fluorine, it will
damage the refrigerant oil).
During any brazing of the refrigerant piping, you must continually blow dry nitrogen gas through the piping to
expel air from the piping. (Fig. 9) If you braze the piping without doing so a large amount of oxide film
develops inside the piping and could cause system failure.
Ensure that you use a pressure reducing valve on the dry nitrogen bottle to prevent pinholes caused by
excessively high pressure. (Set the pressure of nitrogen gas to about 0.2 kg/cm
2
[19.6 kPa])
Table 2
Torque wrench
Spanner
Flare nut
Piping union
Coat here with ether oil
Nitrogen
Refrigerant piping
Tape the pipe
Valve
Nitrogen
Reducing valve
Pipe size
Tightening torque
Flare dimensions A (mm)
Flare
9.5 (3/8")
32.7 - 39.9 N m (333 - 407 kgf cm)
12.8 -13.2
15.9 (5/8")
61.8 - 75.4 N m (630 - 770 kgf cm)
19.3 - 19.7
R0.4 ~ 0.8
A
45
o
±
2
o
90
o
±
2
o
Fig. 7
Fig. 8
Fig. 9
