Hitachi Highly WHP13300PSDPC8FQ Installation Manual page 11

H E A T P U M P W A T E R H E A T E R C O M P R E S S O R C R I T E R I A
14 Impurities in refrigerating system
（1）The weight of residue on the inside surface of the heat exchanger and tube should be
less than 0.01g/m
the weight of foreign residue collected by filer paper after washing inside surface of the
heat exchanger tubes with R-11.
（2）Prevent the impurities from entering into the enclosed unit system used R290. When the
impurities entered into the enclosed system, it will damage the moving mechanism parts
and result in the capillary depositing.
（3）Eliminate all system contaminants such as trichlorethylene, alkalies, soaps, oil, acids
& washing fluid used at machining heat exchanger and tubes.
15 Compressor vacuum operation
Compressor should never be operated while under vacuum. Otherwise, internal arcing can
cause damaging parts.
16 The compressor should be operated for more than 20 seconds within 15 minutes after charging
refrigerant into the system so proper lubrication results.
17 Liquid refrigerant return limitations 有关液体制冷剂回流的限制项目
（1）Liquid refrigerant level in s-tank should be lower
than the top of s-pipe in s-tank.(see chart at right)
(2) There should not exist noise of the liquid refrigerant compression, current and vibrancy
increase. System can append the assistant stank or reduce the amount of refrigerant to
prevent from liquid refrigerant compression. Refrigerant system forbid liquid refrigerant
from flowing back compressor in any case. In normal condition the overheat gas refrigerant
should flow back compressor.
2
. But metallic dust should not be permitted in the system. This value means
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