Mitsubishi Electric PUHY-RP-Y(S)JM-B Data Book page 277

3. Piping Design
3-1-4. Flow chart to check if the existing piping can be reused
Is the refrigerant oil SUNISO, MS,
Barrel Freeze, HAB or Freol?
NO
less between IU and OU (if OU is
below IU, 40m or less). And also, height
NO
NO
NO
Use a new piping. The existing piping can be reused.
Do you know what kind of
NO
refrigerant oil is used in the
existing system?
YES
Please contact your local
distributor.
YES
The vertical height
difference needs to be 50m or
difference between each IU is
15m or less.
YES
Does the piping diameter
and piping length match
our guideline?
YES
NO
Is the branch pipe shape T, Y
or header branching?
YES
Please change to the specified
branch pipe.
Do the existing
NO
pipes hold enough
air tightness?
YES
YES
NO
All branch pipes are connected
with the indoor units.
YES
NO
Is the piping correctly covered
with heat insulation material?
YES
Does the piping meet the
strength requirements?
(material,thickness,anti
corrosion)
YES
SYSTEM DESIGN
Exisiting piping cannot be
reused. Use new piping.
If the piping is left disconnected, there is a
possibility of contamination and corrosion
inside the pipe. Do not reuse such pipes.
Check the branch pipe type
NO
and the reusability standards
to make a decision.
YES
Did the existing unit before the
NO
replacement operate without
any gas leak?
YES
Cut the branch pipe completely that are not
in use, and seal it.
Conduct heat insulation.
Start
Are the existing pipes still
NO
connected with indoor units and the
outdoor units? (excluding sealed
branch pipes that are
not in use)
YES
Is the existing unit
Mitsubishi Electric unit?
NO
YES
Is the capacity of new
replacement unit the same as that
NO
of the existing unit?
YES
Check the piping size and length.
Take the refrigerant oil recovery
procedures described in the Mineral
Oil Collection (Refrigerant Oil
Recovery) Manual.
Please have air tight test on site.
NO
Is the piping air tight?
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