a. The run indicator light (fig. 2-1), the time totalizing meter, and the refrigerant sight glass are the only visual
indicators incorporated in the Air Conditioners.
Figure 2-2. Visual Indicators
(1) The time totalizing meter is used to determine maintenance intervals.
(2) The sight glass is a port window through which the refrigerant condition can be seen. Liquid refrigerant
actually flows through the sight glass chamber only during cooling cycles when the air conditioner is in operation in the
COOL mode. The sight glass is equipped with a center indicator that is moisture sensitive. Dry refrigerant is indicated by
green, it turns to chartreuse when the moisture content becomes undesirable, and to yellow when the level becomes
unacceptable. Excessive moisture in the refrigerant may damage or possibly destroy the compressor. If the liquid
refrigerant observed in the sight glass has an opaque, milky appearance, or frequent bubbles appear, the volume of
refrigerant is low and the system should b charged. Either moisture or low charge indications should be reported to direct
Do not operate the air conditioner in the COOL mode if the refrigerant color has
reached the yellow band or if numerous bubbles appear in the sight glass. COOL
mode operation may be continued with the refrigerant color in the chartreuse band
or with only an occasional bubble appearing in the window but the sight glass
should be rechecked after each four hours of operation to insure that the condition
has not become worse.
Change 6 2-3
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