Desert Aire SelectAire Plus SP Series, Installation And Operation Manual

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Desert Aire - SP Manual
Figure 35 – Exhaust Hood (Final View)
2.17 Combination Moisture and Liquid Indicator
The moisture and liquid indicator combines the two functions of moisture and liquid indication into a single
indicator. Excessive moisture in refrigerant systems can cause unwanted chemistries such as hydrolysis of
lubricants and other materials, corrosion of metals, copper planting, and ice formation at the meeting device.
The indicator is a porous filter paper impregnated with a chemical salt that is sensitive to moisture. The salt
changes color according to the moisture content (relative saturation) in the refrigerant. A dark green color
indicates the refrigerant is DRY and yellow indicates a WET condition. The indicator is formulated so that it
changes color as the moisture levels generally accepted as the safe operating range. The colors indicate the
following moisture content in PPM:
• Dark Green → Less than 75 PPM
• Chartreuse → 75 - 150 PPM
• Yellow → Over 150 PPM
Change the drier when the color is in the caution or wet range. The action of the indicator element is
completely reversible and will change color whenever the moisture content of the system changes. The
indicating element may change color rapidly on some installations, while others may take a much longer
period of time. New systems or systems where the drier has been replaced will cause the indicator to start
changing color almost immediately. However, it is recommended that the equipment operate for 12 hours to
allow the system to reach equilibrium before deciding if the drier should be changed.
The drying of the system should be continued until the indicating element stays Dark Green.
Additional Considerations:
- Bubbles: The Moisture and Liquid Indicator may be installed anywhere in the liquid line. When
located between the Filter-Drier and the expansion device,