Precautions For Devices That Use R407C Refrigerant - Mitsubishi City Multi PURY-P400 Service Handbook

1 1 1 1 1 PRECAUTIONS FOR DEVICES THAT USE R407C REFRIGERANT

Do not use the existing refrigerant piping.
• The old refrigerant and refrigerator oil in the existing
piping contains a large amount of chlorine which may
cause the refrigerator oil of the new unit to deterio-
rate.
Use pipes made of phosphorus deoxidized cover cat-
egorized under H3000 (Copper and copper alloy
seamless pipes and tubes). Be sure that the inner and
outer surfaces of the pipes are clean and free of con-
taminants, such as sulphur, oxides, dust/dirt, shav-
ing particles, oils, and moisture.
• Contaminants on the inside of the refrigerant piping
may cause the refrigerant residual oil to deteriorate.
Store the piping to be used during installation indoors,
and keep both ends of the piping sealed until imme-
diately 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.
Use a small amount of ester oil, ether oil or
alkylbenzene as the refrigerator oil to coat flares
and flange connections.
• The refrigerator oil will degrade if it is mixed with a
large amount of mineral oil.
Use liquid refrigerant to seal the system.
• If gas refrigerant is used to seal the system, the com-
position of the refrigerant in the cylinder will change
and performance may drop.
Do not use a refrigerant other than R407C.
• If another refrigerant (R22, etc.) is used, the chlorine
in the refrigerant may cause the refrigerator oil to de-
teriorate.
Caution
Use a vacuum pump with a reverse flow check valve.
• If other types of valves are used, the vacuum pump oil
may flow back into the refrigerant cycle and cause the
refrigerator oil to deteriorate.
Do not use the following tools that have been used
with conventional refrigerants.
(Gauge manifold, charge hose, gas leak detector, re-
verse flow check valve, refrigerant charge base,
vacuum gauge, refrigerant recovery equipment)
• If the conventional refrigerant and refrigerator oil left
on these tools are mixed in with R407C, the refriger-
ant may deteriorate. If water is mixed in with R407C,
the refrigerator oil may deteriorate. Since R407C
does not contain any chlorine, gas leak detectors for
conventional refrigerants will not operate properly.
• If water is mixed in with R407C, the refrigerator oil
may deteriorate.
• Since R407C does not contain any chlorine, gas
leak detectors for conventional refrigerants will not
operate properly.
Do not use a charging cylinder.
• The use of a charging cylinder may cause the refrig-
erant to deteriorate.
Be especially careful when managing the tools.
• If dust, dirt, or water enters the refrigerant cycle, the
refrigerant may deteriorate.
If the refrigerant leaks, recover the refrigerant in the
refrigerant cycle; then, recharge the cycle with the
specified amount of the liquid refrigerant indicated
on the air conditioner.
• Since R407C is a non-azeotropic refrigerant, if over-
charged, the composition of the refrigerant in the re-
frigerant cycle will change and result in a drop in per-
formance or abnormal stopping.
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