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Air to Water Heat Pump
Installation Manual
15
Appendix
Work instructions
The existing R22 and R407C piping can be reused for
our digital inverter R410A 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
R410A 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 R410A is high (1.6
times that of R22 and R407C). 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 0.8 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 to water heat pump 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 to water heat pump 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
to water heat pump are repeated such as when
leased etc.
9. If the type of 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.
• 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 to water heat pump, but do not guarantee the
use of the existing pipes of air to water heat pump that
have adopted R410A in other companies.
Pipe outer diameter
Ø6.4
Ø9.5
Ø12.7 Ø15.9 Ø19.0
Thickness
R410A
0.8
0.8
0.8
1.0
1.0
26-EN
Summary of Contents for HWS-1105H-E
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