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13
Appendix
Work instructions
The existing R22 and R410A piping can be reused for
inverter R32 product installations.
WARNING
Con
fi
rming the existence of scratches or dents on
the existing pipes and con
fi
rming the reliability of
the pipe strength are conventionally referred to the
local site.
If the speci
fi
ed 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
speci
fi
ed “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 thi ckness (mm)
Pipe outer diameter
Ø6.4
Ø9.5
Ø12.7
Ø15.9
Thickness
R32, R410A
0.8
0.8
0.8
1.0
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 re
fi
lled.
•
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 con
fi
rmed
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 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
Term
Curing manner
Outdoors
1 month or more
Pinching
Less than 1 month
Pinching or taping
Indoors
Every time
Are there scratches or dents on the existing pipes?
Is it possible to operate the existing air conditioner?
y
After the existing air conditioner is operated in
cooling mode for approx. 30 minutes or longer,*
recover the refrigerant.
y
For cleaning the pipes and recovering oil
y
Refrigerant recovery: Pump down method
y
Remove the existing air conditioner from the piping
and carry out
fl
ushing (nitrogen pressure 0.5 MPa)
to remove any remains inside of the pipe.
Note:
In case of twin pipes, also be sure to
fl
ush the
branching pipe.
Connect the indoor / outdoor units to the existing pipe.
y
Use a
fl
are nut attached to the main unit for the
indoor / outdoor units. (Do not use the
fl
are nut of
the existing pipe.)
y
Re-machine the
fl
are machining size to size for R32.
y
(Airtight test), Vacuum dry, Refrigerant charge, Gas
leak check
Test run
Was largely discolored oil or a large quantity
of remains discharged? (When the oil deteriorates,
the color of the oil changes to a muddy or
black color.)
Existing pipes: Cannot be used.
y
Use new pipes.
Clean the pipes or use new pipes.
Piping necessary to change the
fl
are nut /
machining size due to pipe compression
1) Flare nut width: H
H
(mm)
Copper pipe
outer diameter
Ø6.4
Ø9.5
Ø12.7 Ø15.9
For R32, R410A
17
22
26
29
For R22
Same as above
24
27
2) Flare machining size: A
A
(mm)
Copper pipe
outer diameter
Ø6.4
Ø9.5
Ø12.7 Ø15.9
For R32, R410A
9.1
13.2
16.6
19.7
For R22
9.0
13.0
16.2
19.4
Becomes a little larger for R32
Do not apply refrigerator oil to the
fl
are surface.
(If there is discharge of remains, it is judged that a
large quantity of remains are present.)
YES
YES
NO
NO
NO
YES
Nitrogen gas pressure 0.5 MPa
