Instructions For Re-Use Piping Of R22 Or R407C - Toshiba RAV-SM404SDT-E Service Manual

7-6. Instructions for Re-use Piping of R22 or R407C

Instruction of Works:
The existing R22 and R407C piping can be
reused for our digital inverter R410A products
installations.
NOTE)
Confirmation of existence of scratch or dent of the
former pipes to be applied and also confirmation of
reliability of the pipe strength are conventionally
referred to the local site.
If the definite conditions can be cleared,
it is possible to update the existing R22 and
R407C pipes to those for R410A models.
7-6-1. Basic Conditions Needed to Reuse the
Existing Pipe
Check and observe three conditions of 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 is no refrigerant leak.)
7-6-2. Restricted Items to Use the Existing Pipes
In the following cases, the existing pipes cannot 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 the
new pipes for the works.
2. When the thickness of the existing pipe is thinner
than the specified "Pipe diameter and thickness" be
sure to use the new pipes for the works.
• The operating pressure of R410A is high
(1.6 times of R22 and R407C). If there is a scratch
or dent on the pipe or thinner pipe is used, the
pressure strength is poor and may cause break-
age of the pipe at the worst.
∗ Pipe diameter and thickness (mm)
Pipe outer diameter Ø6.4
R410A
0.8
Thickness
R22
(R407C)
• In case that the pipe diameter is Ø12.7 mm or less
and the thickness is less than 0.7 mm, be sure to use
the new pipes for works.
3. The pipes are left as coming out or gas leaks.
(Poor refrigerant)
• There is possibility that rain water or air including
moisture enters in the pipe.
4. Refrigerant recovery is impossible.
(Refrigerant recovery by the pump-down operation
on the existing air conditioner)
• There is possibility that a large quantity of poor
oil or moisture remains inside of the pipe.
5. A dryer on the market is attached to the existing
pipes.
• There is possibility that copper green rust
generated.
Ø9.5 Ø12.7 Ø15.9 Ø19.0
0.8 0.8 1.0 1.0
– 53 –
6. Check the oil when the existing air conditioner was
removed after refrigerant had been recovered.
In this case, if the oil is judged as clearly different
compared with normal oil
• The refrigerator oil is copper rust green :
There is possibility that moisture is mixed with the
oil and rust generates inside of the pipe.
• There is discolored oil, a large quantity of the
remains, or bad smell.
• A large quantity of sparkle remained wear-out
powder is observed in the refrigerator oil.
7. The air conditioner which compressor was ex-
changed due to a faulty compressor.
When the discolored oil, a large quantity of the
remains, mixture of foreign matter, or a large
quantity of sparkle remained wear-out powder is
observed, the cause of trouble will occur.
8. Installation and removal of the air conditioner are
repeated with temporary installation by lease and
etc.
9. In case that type of the 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.
• Winding-insulation of the compressor may
become inferior.
NOTE)
The above descriptions are results of confirmation by
our company and they are views on our air
conditioners, but they do not guarantee the use of the
existing pipes of the air conditioner that adopted
R410A in other companies.
7-6-3. Branching Pipe for Simultaneous
Operation System
• In the concurrent twin system, when TOSHIBA-
specified branching pipe is used, it can be reused.
Branching pipe model name:
RBC-TWP30E-2, RBC-TWP50E-2
On the existing air conditioner for simultaneous
operation system (twin system), there is a case of
using branch pipe that has insufficient compressive
strength.
In this case please change it to the branch pipe for
R410A.
7-6-4. Curing of Pipes
When removing and opening the indoor unit or outdoor
unit for a long time, cure the pipes as follows:
• Otherwise rust may generate when moisture or
foreign matter due to dewing enters in the pipes.
• The rust cannot be removed by cleaning, and a new
piping work is necessary.
Place position Term
1 month or more
Outdoors
Less than 1 month
Indoors Every time
Curing manner
Pinching
Pinching or taping