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Refrigerant piping
8.2 REFRIGERANT PIPE CONNECTIONS
The DX-Interface unit is set up to be connected by Flare Nut (factory supplied). Perform the indicated pipe work by maintaining the
dimensions indicated in the following tables.
Size of pipes
units: mm (inch)
Units
Nominal diameters
EXV-2.0E1
(1/4)
EXV-(2.5-10.0)E1
(3/8)
N O T E
•
Flare nuts tightening torque
•
Always use two wrenches or fix spanners when tightening the
flare nuts on the refrigerant pipes.
•
If any failure occurs during this process the result could be
pipe damage or refrigerant leak.
8.3 BRAZING WORK
C A U T I O N
•
Use nitrogen gas for blowing during pipe brazing. If oxygen,
acetylene or fluorocarbon gas is used, it will cause an explo-
sion or poisonous gas.
•
A rust coating will appear inside of tubes if no nitrogen gas
blowing is performed during brazing work. This film will be
flecked off after operation and will circulate in the circuit, re-
sulting in clogged expansion valves, etc, and the compressor
will be affected.
8.4 REFRIGERANT CHARGE
D A N G E R
•
Do not charge OXYGEN, ACETYLENE, or other flammable
and poisonous gases into the refrigerant circuit, as an explo-
sion could occur. It is recommended that oxygen free nitrogen
be charged for these types of test cycles when performing
a leakage test or an airtight test. These types of gases are
extremely dangerous.
•
Insulate the unions and flare-nuts at the piping connection
part completely.
•
Insulate the liquid piping completely to avoid a decreased per-
formance; if not, it will cause sweating on the surface of the
pipe.
10
Outer
diameters
6.35
9.53
PMML0243A rev.3 - 12/2014
Flare pipe
Minimum thick-
dimensions
ness R410A
A
Ø +0/-0.4
9.1
0.5
13.2
0.6
After connecting the refrigerant piping seal the open space bet-
ween the knockout hole and refrigerant pipes by using insulation
material as shown below:
A. Insulation.
B. Field-supplied refrigeration
piping.
•
Use a reducer valve when nitrogen gas blowing is performed
during brazing. The gas pressure should be maintained within
0.03 to 0.05 Mpa. If excessively high pressure is applied to a
pipe, it will cause an explosion.
•
Charge refrigerant correctly. Overcharging or insufficient char-
ging could cause a compressor failure.
•
Check for refrigerant leakage in detail. If a large refrigerant
leakage occurred, it would cause difficulty with breathing or
harmful gases would occur if a fire were in the room.
•
If the flare nut is tightened too hard, it may crack over time and
cause refrigerant leakage.
N O T E
Please refer to Outdoor unit Installation Manual and Technical
Catalogue for the calculating method of additional refrigerant
charge according the piping length.
Flare nut dimen-
Tightening Torque
sions B
(Nm)
17
20
22
40
A
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