Restrictions On Refrigerant Piping Length - Mitsubishi Electric PURY-P200 Service Handbook

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Restrictions on Refrigerant Piping Length

For the piping connection, the end branching system is applied where the end of refrigerant piping from the outdoor unit is
branched and connected to each indoor unit. As the piping connection method, the indoor unit is applied with flare connec-
tion, outdoor unit gas piping is flange connection, and liquid piping is flare connection. For the branching, brazed connection
is applied.
Warning
Be careful not to leak refrigerant gas (R410A) near a fire. Refrigerant gas if touched a fire of gas oven and the like will
be decomposed to generate poisonous gas leading to gas-poisoning. Do not conduct welding work in a closed room.
Run a gas leak test after completing refrigerant piping work.
Warning
Do not use a refrigerant other than that indicated on
the equipment at installation or movement.
• Mixing of different refrigerant or air makes the refrigeration cycle
abnormal causing breakage and the like.
Caution
Use refrigerant piping phosphorus deoxidized cop-
per. In addition, be sure that the inner and outer sur-
face of the pipes are clean and free of hazardous
sulphur, oxides, dust/dirt, shaving particles, oils,
moisture, or any other contaminant.
• Contaminants on the inside of the refrigerant piping may cause
the refrigerant residual oil to deteriorate.
Caution
Use liquid refrigerant to fill the system.
• If gas refrigerant is used to seal the system, the composition of
the refrigerant in the cylinder will change and performance may
drop.
Caution
Do not use existing refrigerant piping.
• The old refrigerant and refrigerator oil in the existing piping
contains a large amount of chlorine which may cause the
refrigerantor oil of the new unit to deteriorate.
Caution
Store the piping to be used during installation indoors
and keep both ends of the piping sealed until just
before brazing.
(Store elbows and other joints in a plastic bag.)
• If dust, dirt, or water enters the refrigerant cycle,
deterioration of the oil and compressor trouble may result.
Caution
Do not use a charging cylinder.
• Using a charging cylinder may cause the refrigerant to
deteriorate.
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