Mitsubishi Electric PEFY-P40VMH-A Technical & Service Manual page 3

2. Precautions for devices that use
R407C refrigerant
Caution:
• Do not use the existing refrigerant piping.
- The old refrigerant and refrigerator oil in the existing piping con-
tains a large amount of chlorine which may cause the refrigerator
oil of the new unit to deteriorate.
• Use refrigerant piping made of C1220 (CU-DHP) phosphorus
deoxidized copper as specified in the *JIS H3300 "Copper and
copper alloy seamless pipes and tubes". In addition, be sure
that the inner and outer surfaces 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.
*JIS: Japanese Industrial Standard
• 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.
• Use ester oil, ether oil or alkylbenzene (small amount) 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 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.
• Do not use a refrigerant other than R407C.
- If another refrigerant (R22, etc.) is used, the chlorine in the refrig-
erant may cause the refrigerator oil to deteriorate.
• Use a vacuum pump with a reverse flow check valve..
- 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 are used with conventional
refrigerants.
(Gauge manifold, charge hose, gas leak detector, reverse flow
check valve, refrigerant charge base, vacuum gauge, refriger-
ant recovery equipment)
- If the conventional refrigerant and refrigerator oil are mixed in the
R407C, the refrigerant may deteriorated.
- If water is mixed in the R407C, the refrigerator oil may deteriorate.
- Since R407C does not contain any chlorine, gas leak detectors
for conventional refrigerants will not react to it.
• Do not use a charging cylinder.
- Using a charging cylinder may cause the refrigerant to deteriorate.
• Be especially careful when managing the tools.
- If dust, dirt, or water gets in the refrigerant cycle, the refrigerant
may deteriorate.
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