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16
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
R32, R410A
Thickness
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.
Ø6.4 Ø9.5 Ø12.7 Ø15.9
0.8
0.8
0.8
1.0
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
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
location
1 month or more
Outdoors
Less than 1 month
Indoors
‒ 50 ‒
Installation Manual
Term
Curing manner
Pinching
Pinching or taping
Every time
50-EN
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