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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
R32, R410A
Thickness
0.8
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 in other companies.
Curing of pipes
Ø15.9
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
Pinching or taping
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 flushing (nitrogen pressure 0.5 MPa) to
remove any remains inside of the pipe.
Note: In case of twin pipes, also be sure to flush 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 flare nut attached to the main unit for the indoor
/ outdoor units. (Do not use the flare nut of the existing
pipe.)
Re-machine the flare machining size to size for R32.
(Airtight test), Vacuum dry, Refrigerant charge, Gas
leak check
Curing manner
Pinching
– 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 flare nut / machining
1) Flare nut width: H
H
Test run
2) Flare machining size: A
A
Do not apply refrigerator oil to the flare surface.
Existing pipes: Cannot be used.
Use new pipes.
Clean the pipes or use new pipes.
size due to pipe compression
(mm)
Copper pipe
Ø6.4
Ø9.5 Ø12.7 Ø15.9
outer diameter
For R32, R410A
17
22
26
29
For R22
Same as above
24
27
(mm)
Copper pipe outer
Ø6.4
Ø9.5 Ø12.7 Ø15.9
diameter
For R32, R410A
9.1
13.2
16.6
19.7
For R22
9.0
13.0
16.2
19.4
Becomes a little larger for R32
52-EN
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