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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 Air to Water Heat Pump R32 products
installations.
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.
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 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 that the pipe diameter is DIA 12.7 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 to Water Heat Pump)
• 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.
(6) Check the oil when the existing Air to Water Heat
Pump 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 to Water Heat Pump which compressor was
exchanged due to a trouble 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 to Water Heat
Pump are repeated with temporary installation by
lease and etc.
(9) In case that type of the refrigerator oil of the existing
Air to Water Heat Pump 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.
The above descriptions are results of confirmation by
our company and they are views on our Air to Water
Heat Pump, but they do not guarantee the use of the
existing pipes of the Air to Water Heat Pump that
adopted R410A in other companies.
Reference outside
diameter (mm)
Wall thickness
(mm)
Material
6.4 0.8 —
12.7 0.8 —
15.9 1.0 —
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