Supplemental Manual
High-
IsoDry™ RH Control System
©
Copyright 2017 Terra Universal Inc. All rights reserved • Revised November 2020 • Document No. 1788-26
Terra Universal, Inc. • TerraUniversal.com • 800 S. Raymond Ave. • Fullerton, CA 92831 • TEL: (714) 578-6000 • FAX: (714) 578-6020
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purge as long as access doors remain closed.
3.
If you are operating a large desiccator and require a low humidity level, your system may need to
operate on high purge much of the time to compensate for the hygroscopic characteristics of the acrylic
(or static-dissipative PVC) desiccator walls. These materials absorb moisture from outside of the
desiccator and pass it inside. The higher the difference between the external and internal humidity
levels, the more nitrogen you will need in order to remove this moisture. Yet if you operate on high-flow
purge most of the time, you consume large amounts of nitrogen and run the risk of pressure build-ups.
PROBLEM:
The system constantly switches between high and low purge.
POSSIBLE SOLUTIONS:
1.
Make sure that all access doors are fully closed. Check door seals for leaks.
2.
You should increase the flowmeter setting until the Dual Purge System maintains a humidity level a few
percent below the set point without switching to the high-level purge.
PROBLEM:
The desiccator is leaking excessively.
POSSIBLE SOLUTIONS:
1.
Check the condition of the gasket on the desiccator. If it is cracked or peeling, call Terra for a
replacement.
2.
Check door alignment. Leaks may develop if doors are out of alignment.
PROBLEM:
Line pressure gauge does not display any pressure, or displays the “Low Pressure” alarm at all times.
POSSIBLE SOLUTIONS:
1.
Supply gas is down, or for some reason is not reading the Dual Purge system. Check your supply line
for kinks or blockage.
2.
If your gas system utilizes a filter, it may be clogged and need to be replaced.
3.
Check the line pressure regulator to make sure it is not closed
4.
Run the “Zero Calibration” routine described in Section 3.2
