Arrow Pneumatics RH203, Instruction & Maintenance Manual

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E. MOISTURE INDICATOR OPERATION
Moisture Indicator is provided to warn operating personnel of dryer malfunction. If dryer is
functioning properly, desiccant in Moisture Indicator will be blue. Should blue color fade or
turn pink, discontinue dryer use and consult Troubleshooting Guide.
F. OPTIONAL EQUIPMENT (IF APPLICABLE)
1. Dewpoint Demand System (DDS)
A. The function of DDS is to conserve energy by eliminating unnecessary dryer cycling and
heater power consumption.
B. The DDS works by utilizing a moisture sensitive probe to measure the water vapor
content of the outlet air from the drying instantaneously to a change in the moisture
content of air stream. The moisture content of the sample air stream indicates the
wetness of the drying tower’s desiccant bed.
The purpose of the probe and its associated electronics is to first measure the “wetness” of
the air within the desiccant beds and then regenerate the desiccant beds only when the
moisture loading reaches a pre-set maximum dewpoint.
C. Dewpoint Demand System Startup and Operation
1. Put dryer’s auto/manual selector switch in “manual” position.
2. Close DDS sample valve.
3. Pressurize the dryer
4. Energize the dryer. Allow dryer cycle for 8 to 16 hours. Observe that both towers have
completed a full regeneration cycle.