Refrigerant Piping Work; Piping Materials; Piping Connection - Hitachi DXF-2.0A1 Operation Installation Maintenance Manual

4 Refrigerant Piping Work
♦ Connect the Expansion Valve Box to the liquid
pipe as shown in Fig. 2.1.
♦ Refer to Section 2.4 System Overview on page 6
for the limitation of installation.
4.1

Piping Materials

(1) Prepare locally-supplied refrigerant pipes.
(2) Select clean copper pipes. Make sure there
is no dust and moisture inside of the pipes.
Blow the inside of the pipes with nitrogen
or dry air to remove any dust or foreign
materials before connecting pipes.
Do not use any tools such as a saw or a
grinder, which produce a lot of swarf.
● Cautions for Refrigerant Pipe Ends
When installing pipe through the
wall, make sure to cover the end
of the pipe with a plastic bag.
Correct Incorrect
Hole Hole
Attach a cap or cover with
a plastic bag.
Correct Incorrect
Rain can enter
Attach a cap or a
plastic bag with
rubber band.
(3) Select pipe size from the following table.
Pipe Size
Capacity
2HP
4-10HP
12-30HP
4.2

Piping Connection

(1) Refer to Section 3.3 for position of piping
connection.
(2) When tightening the flare nut, use 2
spanners as shown in the figure. Ensure that
no refrigerant leakage occurs.
(3) Support the pipes with clearance towards
the axis to avoid thermal stress.
(4) Ceiling material should be strong enough.
Abnormal noise may be heard due to piping
vibration.
(5) After connecting the refrigerant piping, seal
the refrigerant pipes by using the insulation
material as shown in the figure (field-
supplied).
P5417151-rev.1
Do not place the pipe
directly on the ground.
Correct Incorrect
Attach a cap or cover with
a plastic bag.
inch(mm)
Liquid
1/4 (6.35)
3/8 (9.52)
1/2 (12.7)
Do not apply excessive force to the flare nut
when tightening. It may cause breakage with
aged deterioration and refrigerant leakage. Use
correct torque specification.
Refer to the outdoor unit "Installation &
Maintenance Manual" for refrigerant piping work,
vacuum pumping work and additional refrigerant
charge.
• Flare Nut Dimension
+ 2
90
o o
Diameter
A
1/4 (6.35)
3/8 (9.52)
R0.4 ~ R0.8
1/2 (12.7)
5/8 (15.88)
d
• Required Torque
Pipe Size
1/4 inch (6.35 mm) 10.3 - 13.3 ft·lbs (14 - 18 N·m)
3/8 inch (9.52 mm) 25.1 - 31.0 ft·lbs (34 - 42 N·m)
1/2 inch (12.7 mm) 36.1 - 45.0 ft·lbs (49 - 61 N·m)
5/8 inch (15.88 mm) 50.2 - 60.5 ft·lbs (68 - 82 N·m)
• 2 Spanner Work
• Insulation on Pipes
Unit
side
Insulation material
Cord clamp (3 places)
Use refrigerant R410A in the refrigerant cycle.
Do not charge oxygen, acetylene or other
flammable and poisonous gases into the
refrigerant cycle when performing a leakage
test or an air-tight test. These types of gases
are extremely dangerous and may cause an
explosion. Use compressed air, nitrogen or
refrigerant for these types of tests.
inch (mm)
+0
A
-0.02 (-0.4)
(d)
R410A
0.36 (9.1)
0.52 (13.2)
0.65 (16.6)
0.78 (19.7)
(JIS B 8607)
Tightening Torque
Refrigerant pipe
Insulation for
refrigerant pipe
Insulation for refrigerant pipe
19