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12
Appendix
Work instructions
The existing R22 and R410A piping can be reused for
inverter R32 product installations.
WARNING
Confirming the existence of scratches or dents on
the existing pipes and confirming the reliability of
the pipe strength are conventionally referred to the
local site.
If the specified conditions can be cleared, it is
possible to update existing R22 and R410A pipes
to those for R32 models.
Basic conditions needed to reuse existing
pipes
Check and observe the presence of three conditions in
the refrigerant piping works.
1. Dry (There is no moisture inside of the pipes.)
2. Clean (There is no dust inside of the pipes.)
3. Tight (There are no refrigerant leaks.)
Restrictions for use of existing pipes
In the following cases, the existing pipes should
not be reused as they are. Clean the existing pipes
or exchange them with new pipes.
1. When a scratch or dent is heavy, be sure to use new
pipes for the refrigerant piping works.
2. When the existing pipe thickness is thinner than the
specified "Pipe diameter and thickness," be sure to
use new pipes for the refrigerant piping works.
The operating pressure of refrigerant is high. If there
is a scratch or dent on the pipe or a thinner pipe is
used, the pressure strength may be inadequate,
which may cause the pipe to break in the worst case.
* Pipe diameter and thickness (mm)
Pipe outer diameter
Ø6.4
Ø9.5
Ø12.7 Ø15.9
R32, R410A
Thickness
0.8
0.8
R22
3. When the outdoor unit was left with the pipes
disconnected, or the gas leaked from the pipes and
the pipes were not repaired and refilled.
There is the possibility of rain water or air, including
moisture, entering the pipe.
4. When refrigerant cannot be recovered using a
refrigerant recovery unit.
There is the possibility that a large quantity of dirty
oil or moisture remains inside the pipes.
51-EN
5. When a commercially available dryer is attached to the
existing pipes.
There is the possibility that copper green rust has
been generated.
6. When the existing air conditioner is removed after
refrigerant has been recovered.
Check if the oil is judged to be clearly different from
normal oil.
The refrigerator oil is copper rust green in color:
There is the possibility that moisture has mixed with
the oil and rust has been generated inside the pipe.
There is discolored oil, a large quantity of residue,
or a bad smell.
A large quantity of shiny metal dust or other wear
residue can be seen in the refrigerant oil.
7. When the air conditioner has a history of the
compressor failing and being replaced.
When discolored oil, a large quantity of residue,
shiny metal dust, or other wear residue or mixture of
foreign matter is observed, trouble will occur.
8. When temporary installation and removal of the air
conditioner are repeated such as when leased etc.
9. If the type of refrigerator oil of the existing air
conditioner is other than the following oil (Mineral oil),
Suniso, Freol-S, MS (Synthetic oil), alkyl benzene
(HAB, Barrel-freeze), ester series, PVE only of ether
series.
The winding-insulation of the compressor may
deteriorate.
NOTE
The above descriptions are results have been confirmed
by our company and represent our views on our air
conditioners, but do not guarantee the use of the existing
pipes of air conditioners that have adopted R32, R410A
in other companies.
Curing of pipes
0.8
1.0
When removing and opening the indoor or outdoor unit for
a long time, cure the pipes as follows:
Otherwise rust may be generated when moisture or
foreign matter due to condensation enters the pipes.
The rust cannot be removed by cleaning, and new
pipes are necessary.
Placement
Term
location
1 month or more
Outdoors
Less than 1 month
Indoors
Every time
Are there scratches or dents on the existing pipes?
Is it possible to operate the existing air conditioner?
After the existing air conditioner is operated in cooling
mode for approx. 30 minutes or longer,* recover the
refrigerant.
For cleaning the pipes and recovering oil
Refrigerant recovery: Pump down method
Remove the existing air conditioner from the piping
and carry out fiushing (nitrogen pressure 0.5 MPa) to
remove any remains inside of the pipe.
Note: In case of twin pipes, also be sure to fiush the
branching pipe.
Was largely discolored oil or a large quantity
of remains discharged? (When the oil deteriorates,
the color of the oil changes to a muddy
Connect the indoor / outdoor units to the existing pipe.
Use a fiare nut attached to the main unit for the indoor
/ outdoor units. (Do not use the fiare nut of the existing
pipe.)
Re-machine the fiare machining size to size for R32,
R410A .
(Airtight test), Vacuum dry, Refrigerant charge, Gas
leak check
Curing manner
Pinching
Pinching or taping
– 26 –
YES
NO
NO
YES
Nitrogen gas pressure 0.5 MPa
(If there is discharge of remains, it is judged that a
large quantity of remains are present.)
YES
or black color.)
NO
Piping necessary to change the fiare nut / machining
1) Flare nut width: H
Copper pipe
outer diameter
For R32, R410A
H
For R22
Test run
2) Flare machining size: A
Copper pipe
outer diameter
A
For R32, R410A
For R22
Becomes a little larger for R32, R410A
Do not apply refrigerator oil to the fiare surface.
Existing pipes: Cannot be used.
Use new pipes.
Clean the pipes or use new pipes.
size due to pipe compression
(mm)
Ø6.4
Ø9.5
Ø12.7 Ø15.9
17
22
26
29
Same as above
24
27
(mm)
Ø6.4
Ø9.5
Ø12.7 Ø15.9
9.1
13.2
16.6
19.7
EN
9.0
13.0
16.2
19.4
ID
ID
52-EN
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