Hitachi MC-20AN Installation Manual page 4

INSTALLATION MANUAL
FOR MULTI-KITS
4.4. PIPIng connectIon
1. Use clean copper pipes without any moisture or foreign
materials on inner surface of pipes. When connecting
refrigerant pipe, cut the copper pipes with a pipe cutter as
shown below.
Also blow the pipes with nitrogen or air to remain no dust
inside the pipe.
Do NOT use a saw, a grindstone or others which causes a
large amount of cutting powder.
B
A
C
D
2. When cutting the pipe, secure the adequate depth for brazing
as shown in the following table.
A: Outer Diameter
Over 5, Below 8
Over 8, Below 12
Over 12, Below 16
Over 16, Below 25
Over 25, Below 35
Over 35, Below 45
¡
Caution for Refrigerant Piping
Cover the end of the pipe appropriately when it is to be
−
inserted through holes in walls and roofs, etc.
Keep the ends of the pipes covered while other installation
−
work is being carried out to avoid the entry of dampness or
dirt.
Do not place the pipes directly on the ground without
−
appropriate protection or adhesive vinyl tape to cover the
ends.
−
Where the pipe installation is not completed for a certain
amount of time, weld the ends of the pipe to seal. Then fill
with oxygen-free nitrogen gas through a Schrader valve to
avoid the accumulation of damp and/or contamination due to
dirt.
A Pipe
B Pipe Cutter
C Connection part
D Burring
(mm)
B: Minimum Depth
6
7
8
10
12
14
B
3. Make sure that all stop valves of the outdoor unit are closed
completely.
4. Blow the inside of the pipes with nitrogen gas when brazing.

DANGER
Check for the refrigerant leakage carefully.
If large amount of refrigerant leakage occurs, it will cause to
breathe with difficulty or to generate harmful gas due to the
fire.
5. The air tight test pressure of this product is 4.15MPa.
6. Apply the insulation supplied with this multi-kits to each
branch (liquid side and gas side) with a tape. Also apply the
field-supplied insulation to the field-supplied pipes.

NOTE:
When polyethylene foam is applied, a thickness of 10mm
for liquid piping and 15mm to 20mm for gas piping is
recommended. (Use the insulation with heat resistance of
100 º C for gas piping.)
A
A
B
C
D

CAUTION:
−
Perform the insulation work when the pipe surface
temperature decreases to the room temperature.
If insulation work is performed immediately after brazing,
insulation may melt.
−
If the ends of pipe are open to the atmosphere for a while
after performing piping work, securely put caps or plastic
bags over the pipe ends for avoiding moisture or dust.
After installation, it is recommended to keep this manual by a
customer.
P5414715, PMML0206A-rev.2 - 01/2011
A Insulation
(Field-Supplied)
B Insulation for Gas and
Liquid Line (Accessory)
C Do not leave a gap
between the insulation
Fix the insulation with tape
D
(accessory) completely
after taping temporary
4