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Appendix
[1] Existing piping
Work instructions
The existing R22 and R407C piping can be reused for
our digital 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 R407C 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 R32 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)
• In case the pipe diameter is Ø12.7 mm or less and
the thickness is less than 0.7 mm, be sure to use
new pipes for the refrigerant piping works.
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.
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 or R410A in other companies.
Reference
outside diameter
(mm)
Wall thickness
(mm)
Material
6.4
0.8
—
9.5
0.8
—
12.7
0.8
—
15.9
1.0
—
19.1
1.2
—
22.2
1.0
Half hard
28.6
1.0
Half hard
Branching pipe for simultaneous
operation system
In the concurrent twin system, when TOSHIBA has
specified that branching pipe is to be used, it can be
reused.
Branching pipe model name:
RBC-TWP101E, RBC-TRP100E, RBC-DTWP101E
On the existing air conditioner for simultaneous
operation system (twin, triple, double twin system),
there are cases of branch pipes being used that have
insufficient compressive strength.
In such case, please change the piping to a branch
pipe for R32 or R410A.
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
Term
Curing manner
Outdoors
1 month or more
Pinching
Less than 1 month
Pinching or taping
Indoors
Every time
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