Mitsubishi Electric CITY MULTI PVFY-P12NAMU-E Technical & Service Manual page 4

Precautions for handling units for use with R410A
CAUTION
Do not use the existing refrigerant piping.
A large amount of chlorine that may be contained in the re-
sidual refrigerant and refrigerator oil in the existing piping
may cause the refrigerator oil in the new unit to deteriorate.
Use refrigerant piping materials made of phosphorus deox-
idized copper. Keep the inner and outer surfaces of the
pipes clean and free of such contaminants as sulfur, oxides,
dust, dirt, shaving particles, oil, and moisture.
Contaminants in the refrigerant piping may cause the refrig-
erator oil to deteriorate.
Store the piping materials indoors, and keep both ends of
the pipes sealed until immediately before brazing. (Keep el-
bows and other joints wrapped in plastic.)
Infiltration of dust, dirt, or water into the refrigerant system
may cause the refrigerator oil to deteriorate or cause the
compressor to malfunction.
Use a small amount of ester oil, ether oil, or alkyl benzene
to coat flares and flanges.
Infiltration of a large amount of mineral oil may cause the re-
frigerator oil to deteriorate.
Charge the system with refrigerant in the liquid phase.
If gaseous refrigerant is drawn out of the cylinder first, the
composition of the remaining refrigerant in the cylinder will
change and become unsuitable for use.
HWE1405A
Only use R410A.
The use of other types of refrigerant that contain chloride
may cause the refrigerator oil to deteriorate.
Use a vacuum pump with a check valve.
If a vacuum pump that is not equipped with a check valve is
used, the vacuum pump oil may flow into the refrigerant cy-
cle and cause the refrigerator oil to deteriorate.
Prepare tools for exclusive use with R 410A. Do not use the
following tools if they have been used with the conventional
refrigerant: gauge manifold, charging hose, gas leak detec-
tor, check valve, refrigerant charge base, vacuum gauge,
and refrigerant recovery equipment.
If the refrigerant or the refrigerator oil that may be left on these
tools are mixed in with R410A, it may cause the refrigerator oil
in the new system to deteriorate.
Infiltration of water may cause the refrigerator oil to deteriorate.
Leak detectors for conventional refrigerants will not detect an
R410A leak because R410A is free of chlorine.
Do not use a charging cylinder.
If a charging cylinder is used, the composition of the refrigerant
in the cylinder will change and become unsuitable for use.
Exercise special care when handling tools for use with R410A.
Infiltration of dust, dirt, or water into the refrigerant system
may cause the refrigerator oil to deteriorate.
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