47
Duct Type Split Air Conditioner
Service Manual
3 REFRIGERATION PIPING WORK 
3.1 Refrigeration Piping Work Procedures 
1).  Align the ared end of the copper pipe with the center of the thread joint. Manually tighten the ared 
end nut.
2).  Use torque spanner to tighten the ared end nut until the spanner clatters.    
Fitting Pipe for
Indoor unit
Flaring Nuts
Fitting Pipe
Spanner
Torque Spanner 
 
3.2 Caution in Connecting Pipes
Note: Do not loosen the cap of the pipes when connecting the pipes between the indoor unit 
and the outdoor unit. Connecting the pipes as soon as possible after loosening the cap of the pipes 
to avoid the entering of water and dust. A metal pipe should be utilized if a pipe should be installed 
through a wall.
1).  The connection of the pipes should conrm to the following principles: 
2).  Make sure to lessen the length of connecting pipe, the height difference between the 
indoor and outdoor unit, and the number of bends, and enlarge the diameter of bends.
The permitted maximum value of each case
Height difference between the indoor and outdoor unit
<
30m
90
0
 Number of bends
<
12
Length of connecting pipes
<
50m
The pipe meld type could be employed for the connection of the pipes between the indoor and outdoor 
units.
The pipe joint should be tightly connected when a pipe joint is employed between two pipes. It is better to 
use only one connecting pipe if the distance is not far.
The pipes should not be shriveled when the pipes are connecting. The bend diameter should be longer 
than 200 millimeter. The connecting pipes should not be extended or curved frequently and the curving process 
should not be larger than 3 times in the same bending position.
3.3 Specication of Connection Pipe 
Model
External Diameter
Maximum Length
of  Connection Pipe
(m)
Maximum Difference in 
Height between Outdoor 
and Indoor Unit (m)
Max.No. of 
elbows. (90
o
)
Additional 
Charge of 
Refrigerant (g/m)
Gas Pipe
(Inch)
Liquid Pipe
(Inch)
FG20/BNa-M
3/4″ 3/8″ 50 30 12 60
FGR20/BNa-M
FG25/CNa-M
1″ 3/8″ 50 30 12 60
FGR25/CNa-M
FG30/BNa-M
9/8″ 1/2″ 50 30 12 120
FGR30/BNa-M
FG40/BNa-M
9/8″ 5/8″ 50 30 12 170
FGR40/BNa-M