Toshiba RAV-SM2244AT7 Service Manual Download Page 42

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6-6. 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.

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 definite conditions can be cleared,
it is possible to update the existing R22 and
R407C pipes to those for R410A models.

6-6-1. 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.)

6-6-2. 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)

5. A dryer on the market is attached to the existing pipes.

• There is possibility that copper green rust

generated.

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.

6-6-3. 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, RBC-TRP100E
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.

6-6-4. 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.

• 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.